10 ;VERSION OF OHIO SCIENTIFIC 6500 ASSEMBLER/EDITOR
   20 ;WITH MODIFICATION TO REDUCE MEMORY USAGE, BUT
   30 ;WITH P-CODE INTERPRETER WRITTEN IN 6502 CODE.
   40 ;
   50 ;UK101 MONITOR SUBROUTINES USED BY ASSEMBLER:
   60 CIN = $FFEB ;GET CHARACTER FROM KEYBOARD
   70 COUT = $FFEE ;PRINT CHARACTER
   80 LOAD = $FFF4 ;SET LOAD FLAG
   90 SAVE = $FFF7 ;SET SAVE FLAG
  100 ;
  110 ;VARIABLES IN ZERO PAGE ;16 BITS
  120 ;UNLESS STATE OTHERWISE
  130 ;"*" INDICATES THAT LABEL UPDATED IN PROG BODY
  140 LABTBL = $0A ;START OF LABEL TABLE
  150 TXTPOS = $10 ;CURRENT POSITION IN TEXT
  160 LINLEN = $12 ;LENGTH OF CURRENT SOURCE LINE
  170 LINENO = $14 ;LINE NUMBER DURING ASSEMBLY
  180 STTEXT = $16 ;START OF TEXT MEMORY
  190 ENDMEM = $18 ;END OF AVAILABLE MEMORY
  200 ENDTXT = $1A ;END OF SOURCE TEXT
  210 ;DRTYPE USED FOR OTHER FUNCTIONS THAN DIRECTIVES
  220 DRTYPE = $1E ;(8 BITS) 0=.END, 1=.BYT, 2=.WOR, 3=
  230 IP = $24 ;INTERPRETIVE POINTER FOR P-CODE
  240 INSLEN = $2A ;PCODE INSTR LEN (8-BIT)
  250 CONST0 = $2C ;PERMANENTLY SET TO ZERO
  260 CNST14 = $38 ;PREMANENTLY SET TO $0014
  270 CNST10 = $3C ;PERMANENTLY SET TO 10
  280 ASMBRK = $3E ;SET TO 1 IF ASM ADDR CHANGES
  290 PASS = $40 ;ASSEMBLY PASS (1 OR 2)
  300 CONST1 = $42 ;PERMANENTLY SET TO 1
  310 ASMADR = $44 ;ASSEMBLY ADDRESS
  320 ASMOPT = $48 ;ASSEMBLY OPTION (0, 1, 2 OR 3)
  330 CONST3 = $4A ;PERMANENTLY SET TO 3
  340 INSTLN = $4C ;NUMBER OF BYTES IN CURRENT INSTRUCT
  350 NOPBYT = $4E ;PERMANENTLY SET TO $EAEA
  360 INSTRN = $50 ;CURRENT INSTRUCTION (3 BYTES)
  370 CNST80 = $58 ;PERMANENTLY SET TO $80
  380 BUFADR = $68 ;START ADDR OF CODE IN A2 BUFFER
  390 NUMVAL = $6A ;NUMERIC VALUE FROM EXPRESSION
  400 LABL40 = $6C ;LABEL IN BASE-40 (4 BYTES)
  410 ASMOFS = $70 ;OFFSET FOR ASSEMBLY TO MEMORY
  420 CNST50 = $72 ;PERMANENTLY SET TO $0050
  430 CONST2 = $74 ;PERMANENTLY SET TO 2
  440 CNST12 = $76 ;PERMANENTLY SET TO 12
  450 CNST7E = $78 ;PERMANENTLY SET TO $007E
  460 CNST6C = $7A ;PERMANENTLY SET TO $006C
  470 LABVAL = $7E ;VALUE OF LABEL
  480 A2BUFF = $B8 ;18 BYTES BUFFER FOR A2 (TO $CF)
  490 A2BLEN = $D1 ;LENGTH OF BUFFER FOR A2
  500 CHKSUM = $D2 ;CHECKSUM FOR A2 OPTION
  510 CNST44 = $D4 ;PERMANENTLY SET TO $0044
  520 NUMERR = $E2 ;NUMBER OF CURRENT ERRORS
  530 TMPLOC = $E6 ;TEMPORARY STORAGE
  540 CONST4 = $EA ;PERMANENTLY SET TO 4
  550 PRFLAG = $F0 ;IF 1, SOURCE LINE WAS PRINTED
  560 CONST5 = $F2 ;PERMANENTLY SET TO 5
  570 CONST6 = $F4 ;PERMANENTLY SET TO 6
  580 ERRMSG = $F6 ;CURRENT ERRORS (4 BYTES)
  590 CALADR = $FA ;ADDRESS OF CALLING INSTR
  600 ;
  610 ;DEFINITIONS OF P-CODE MNEMONICS
  620 NXLN = $00 ;USED BY LINE EDITOR
  630 BMOV = $01 ;XX=LEN, YY=SRC, ZZ=DST
  640 LIN1 = $02 ;USED BY LINE EDITOR
  650 CLAS = $03 ;CLASSIFY CHARACTER
  660 LRAN = $04 ;DECODE LINE NUMBER RANGE
  670 SKIP = $05 ;SKIP SPACES
  680 LVAL = $06 ;LOOK UP LABEL AS LVALUE
  690 LEXP = $07 ;LOOK UP LABEL IN EXPRESSION
  700 OUTP = $08 ;OUTPUT ASSEMBLER INSTRUCTION
  710 EXPR = $09 ;EVALUATE EXPRESSION
  720 RLBL = $0A ;READ LABEL
  730 BRGR = $2B ;BRANCH IF XX>YY
  740 BEQU = $4B ;BRANCH IF XX=YY
  750 BGEQ = $6B ;BRANCH IF XX>=YY
  760 BLES = $8B ;BRANCH IF XX<YY
  770 BNEQ = $AB ;BRANCH IF XX<>YY
  780 BLEQ = $CB ;BRANCH IF XX<=YY
  790 COMP = $0C ;COMPRESS SOURCE CODE
  800 KBLN = $0D ;READ LINE FROM KEYBOARD
  810 RET4 = $0E ;RETURN USING OFFSET IN 4TH BYTE
  820 SET0 = $0F ;SET XX TO 0
  830 DCIN = $10 ;INPUT DECIMAL NUMBER
  840 RETN = $11 ;RETURN FROM P-CODE SUBROUTINE
  850 RET2 = $12 ;RETURN USING OFFSET IN 2ND BYTE
  860 INCR = $13 ;INCREMENT XX
  870 DECR = $14 ;DECREMENT XX
  880 EX65 = $15 ;EXECUTE 6502 CODE
  890 COPY = $16 ;COPY XX TO YY
  900 PHEX = $17 ;PRINT XX AS HEX NUMBER
  910 RERR = $18 ;RECORD ERROR XX
  920 PDEC = $19 ;PRINT DECIMAL NUMBER IN XX
  930 PLIN = $1B ;PRINT LINE POINTED TO BY XX
  940 GERR = $1C ;GET ERROR CODE AND PUT IT IN XX
  950 PERR = $1D ;PRINT PTR TO ERROR PLUS MESSAGE
  960 MSLN = $1E ;PRINT NEW LINE PLUS MESSAGE
  970 PER6 = $1F ;AS FOR PERR BUT INCR $06 FIRST
  980 SUBZ = $20 ;SUBTRACT: ZZ = XX - YY
  990 ADDZ = $21 ;ADD: ZZ = XX + YY
 1000 MOVB = $22 ;MOVE BYTE IN (00) TO (XX)
 1010 DCMP = $23 ;DECOMP LINE AT (10); STORE IN (02)
 1020 MESG = $24 ;PRINT MESSAGE WITHOUT NEW LINE
 1030 RET3 = $25 ;RETURN USING OFFTSET IN 3RD BYTE
 1040 CHK0 = $65 ;CHECK CHAR WITH PTR AT 00/01
 1050 CHK6 = $10 ;CHECK CHAR WITH PTR AT 06/07
 1060 INC0 = $28 ;INCREMENT 00/01
 1070 SET1 = $29 ;SET XX TO 1
 1080 ;
 1090 ;CODES FOR USE WITH CHK0 OPCODE:
 1100 CAP = $80
 1110 DCM = $81
 1120 SPC = $82
 1130 ;
 1140 LOMEM = $0240 ;BOTTOM OF AVAILABLE MEMORY 
 1150 ;MAIN ENTRY POINT FOR ASSEMBLER
 1160 *=$7260
 1170 HIMEM = *-1
 1180 ;INITIALISE STACK POINTER
 1190        LDX #$FF
 1200        TXS 
 1210 ;
 1220 ;SET ALL OF ZERO PAGE TO 00
 1230        INX ;X = 0
 1240        TXA ;A = 0
 1250 INITZP STA $00,X
 1260        INX 
 1270        BNE INITZP
 1280 ;
 1290 ;INITIALISE LOCATIONS IN ZERO PAGE, USING
 1300 ;ADDRESSES STARTING AT ZPADDR AND CONTENTS
 1310 ;STARTING AT ZPCONT
 1320 L1168  LDY ZPADDR,X
 1330        LDA ZPCONT,X
 1340        STA $0000,Y
 1350        INX 
 1360        CPX #ZPCONT-ZPADDR ;LENGTH OF TABLE
 1370        BNE L1168
 1380 ;
 1390 ;MAIN P-CODE INSTRUCTION EXECUTION LOOP
 1400 L1179  LDA ENDTXT ;UPDATE RECORD OF END OF TEXT
 1410        STA ENDIMG
 1420        LDA ENDTXT+1
 1430        STA ENDIMG+1
 1440 ;GET OPCODE - X IS OPCODE ACTUALLY EXECUTED
 1450        LDY #$00
 1460        LDA (IP),Y
 1470        LDX #$1A
 1480        CMP #$E8
 1490        BCS LDADDR
 1500        LDX #$0B
 1510        AND #$1F
 1520        CMP #$0B
 1530        BEQ LDADDR
 1540        LDA (IP),Y
 1550        LDX #$26
 1560        CMP #$72
 1570        BCS LDADDR
 1580        INX 
 1590        CMP #$3A
 1600        BCS LDADDR
 1610        TAX 
 1620 ;
 1630 ;X NOW CONTAINS OPCODE TO EXECUTE, SO
 1640 ;SET TMPLOC/TMPLOC+1 TO OPCODE ROUTINE
 1650 LDADDR LDA ADDRLO,X
 1660        STA TMPLOC
 1670        LDA ADDRHI,X
 1680        PHA 
 1690        AND #%00001111
 1700        CLC 
 1710        ADC #OF6502/256
 1720        STA TMPLOC+1
 1730 ;
 1740 ;PUT LENGTH OF INSTRUCTION INTO INSLEN
 1750        PLA 
 1760        LSR A 
 1770        LSR A
 1780        LSR A
 1790        LSR A 
 1800        STA INSLEN
 1810 ;
 1820 ;GO TO L11B7 IF OPCODE IS ITSELF WRITTEN IN
 1830 ;P-CODE (OPCODES 00,...,0A)
 1840        CPX #$0B
 1850        BCC L11B7
 1860        INY ;Y = 1
 1870        LDA (IP),Y ;A = 2ND BYTE OF INSTRUCTION
 1880        LDX #0 ;X = 0
 1890 ;EXECUTE OPCODE ;A = 2ND BYTE OF INSTRUCTION
 1900 ;X=0, Y=1, C=1, AND Z=1
 1910        JMP (TMPLOC)
 1920 ;
 1930 ;OPCODE IS LESS THAN $0B, SO THE ROUTINE IS 
 1940 ;NOT IN 6502 MACHINE CODE, BUT IN P-CODE.
 1950 L11B7  LDA INSLEN
 1960        PHA ;PUSH LENGTH OF INSTRUCTION
 1970        LDA IP+1 ;AND PUSH RETURN ADDRESS
 1980 ;STORE CALL ADDRESS
 1990        STA CALADR+1
 2000        PHA 
 2010        LDA IP
 2020        STA CALADR
 2030        PHA 
 2040        LDX TMPLOC
 2050        LDA TMPLOC+1
 2060 L11CA  STX IP
 2070        STA IP+1
 2080        BNE L1179 ;ALWAYS BRANCHES - GO BACK TO EXE
 2090 ;
 2100 OF6502=*/256*256
 2110 ;OPCODE $14 XX
 2120 ;DECREMENT 16-BIT VALUE IN XX/XX+1
 2130 L02DC  LDY #$FF
 2140        CLC 
 2150        .BYTE $2C
 2160 ;
 2170 ;OPCODE $13 XX
 2180 ;INCREMENT 16-BIT VALUE IN XX/XX+1
 2190 L02D0  TAX 
 2200 ;
 2210 ;OPCODE $28
 2220 ;INCREMENT 16-BIT VALUE IN 00/01
 2230 L11CE  DEY 
 2240        TYA 
 2250        ADC $00,X
 2260        PHA 
 2270        TYA 
 2280        ADC $01,X
 2290 PULLZP STA $01,X
 2300        PLA 
 2310        STA $00,X
 2320 ;ADD INSTRUCTION LENGTH ONTO INTERPRETIVE POINTER
 2330 ;THEN EXECUTE NEXT INSTRUCTION
 2340 L11CF  LDA INSLEN
 2350        BNE L02AA ;ALWAYS BRANCHES
 2360 ;EXECUTE P-CODE - PULL ADDRESS OFF STACK
 2370 L11DC  PLA 
 2380        STA IP
 2390        PLA 
 2400        STA IP+1
 2410        LDA #$01
 2420        BNE L02AA
 2430 DELCHR TYA 
 2440        BEQ L020C
 2450        LDA #$08
 2460        JSR COUT
 2470        LDA #$20
 2480        JSR COUT
 2490        LDA #$08
 2500        JSR COUT
 2510 ;
 2520 ;OPCODE $0D
 2530 ;INPUT LINE OF TEXT FROM THE KEYBOARD.
 2540 ;START ADDRESS OF LINE IS HELD IN $02/$03,
 2550 ;AND MAXIMUM LENGTH OF LINE IS 56 CHARACTERS
 2560 L0205  DEY 
 2570 ;GET A CHARACTER FROM THE KEYBOARD
 2580 L020C  JSR CIN
 2590        CMP #$1C
 2600        BEQ DELCHR
 2610        STA ($02),Y
 2620        CMP #$0D
 2630        BEQ L0235
 2640        CPY #$37
 2650        BEQ L020C
 2660        CMP #$20
 2670        BMI L020C
 2680        JSR COUT
 2690 L0229  INY 
 2700        BNE L020C
 2710 L0235  JSR COUT
 2720        LDA $02
 2730        STA $00
 2740        BNE JL11CF ;ALWAYS BRANCHES
 2750 ;
 2760 ;OPCODE $27 YY
 2770 ;CHECKS NEXT CHARACTER IN TEXT,
 2780 ;USING POINTER AT $06/$07
 2790 ;THE OPCODE $27 DOES NOT APPEAR IN THE CODE
 2800 ;XX IS THE OPCODE MINUS $10 FOR OPCODE $27,
 2810 ;AND THE OPCODE MINUS $65 FOR OPCODE $26
 2820 ;IF XX < $80 IT CHECKS FOR CHARACTER XX
 2830 ;IF XX = $80 (CAP), CHECKS FOR A CAPITAL LETTER
 2840 ;IF XX = $81 (DEC), CHECKS FOR A DECIMAL DIGIT
 2850 ;IF XX = $82 (SPC), CHECKS FOR CONTROL CHAR OR SP
 2860 ;THE SECOND BYTE, YY, IS THE BRANCH OFFSET
 2870 L0244  LDX #$06 ;X IDENTIFIES TEXT POINTER
 2880 ;$EF IS THE COMPLEMENT OF $10, BUT MINUS
 2890 ;1 BECAUSE THE CARRY FLAG IS ALWAYS SET
 2900        LDA #$EF
 2910        .BYTE $2C
 2920 ;
 2930 ;OPCODE $26 - INSTRUCTION LENGTH = 2
 2940 ;SAME AS OPCODE $27 BUT USES POINTER AT $00/$01
 2950 ;X HAS BEEN SET TO ZERO ANYWAY
 2960 ;SECOND BYTE IS RELATIVE BRANCH OFFSET
 2970 ;THE OPCODE $26 DOES NOT APPEAR IN THE CODE
 2980 ;$9A IS THE COMPLEMENT OF $65, BUT MINUS
 2990 ;1 BECAUSE THE CARRY FLAG IS ALWAYS SET
 3000 L0240  LDA #$9A
 3010        DEY 
 3020        ADC (IP),Y
 3030        BMI L0256
 3040        EOR ($00,X)
 3050        BNE JL11CF ;GO ON TO NEXT INSTRUCTION
 3060 ;BRANCH USING SECOND BYTE OF INSTRUCTION
 3070 L0251  LDY #$01
 3080        BNE L0284 ;ALWAYS BRANCHES
 3090 ;
 3100 ;OPCODES $0E, $25 AND $12 - INSTR LEN = 1
 3110 OP1203 INY ;4TH BYTE OF CALL IS BRANCH OFFSET
 3120 OP1202 INY ;3RD BYTE OF CALL IS BRANCH OFFSET
 3130 OP1201 INX ;2ND BYTE OF CALL IS BRANCH OFFSET
 3140 ;
 3150 ;OPCODE $11 - INSTRUCTION LENGTH = 1 
 3160 ;RETURN FROM P-CODE SUBROUTINE
 3170 L02BC  PLA 
 3180        STA IP
 3190        PLA 
 3200        STA IP+1
 3210        PLA 
 3220        DEX 
 3230        BMI L02AA ;NEXT INSTRUCTION IF NO BRANCH
 3240 ;RELATIVE BRANCH, WHERE Y INDEXES THE SIGNED
 3250 ;8-BIT OFFSET
 3260 L0284  LDA (IP),Y
 3270        TAX 
 3280        CLC 
 3290        ADC IP
 3300        STA IP
 3310        TXA 
 3320        AND #$80 
 3330        BEQ L0295
 3340        LDA #$FF
 3350 L0295  ADC IP+1
 3360        STA IP+1
 3370 ;ADD Y REGISTER ONTO INTERPRETIVE POINTER
 3380 ;THEN CONTINUE WITH P-CODE EXECUTION
 3390 L02A9  TYA 
 3400 L02AA  CLC 
 3410        ADC IP
 3420        STA IP
 3430        BCC L1220
 3440        INC IP+1
 3450 L1220  JMP L1179 ;GO TO EXECUTE NEXT INSTRUCTION 
 3460 ;SEE IF THE NEXT CHARACTER FORM THE SOURCE CODE I
 3470 ;A=$80 = CAPITAL LETTER
 3480 ;A=$81 = DECIMAL DIGIT
 3490 ;A=$82 = CONTROL CHARACTER (LESS THAN $20) OR SPA
 3500 L0256  TAY 
 3510        LDA ($00,X)
 3520        CMP L0267-$80,Y
 3530        BMI JL11CF
 3540        CMP L026B-$80,Y
 3550        BMI L0251
 3560        BPL JL11CF
 3570 L0267  .BYTE $41,$30,$00
 3580 L026B  .BYTE $5B,$3A,$21
 3590 ;
 3600 ;OPCODE $16 XX YY
 3610 ;COPY 16-BIT NUMBER FROM XX/XX+1 TO YY/YY+1
 3620 ;IF MSB OF XX IS SET, IT INDEXES CALLING P-CODE 
 3630 L0270  JSR L04A0 ;GET NEXT ARGUMENT IN LIST
 3640        BCS COPY16 ;ALWAYS BRANCHES
 3650 ;
 3660 ;OPCODES $0F YY AND $29 FF
 3670 ;LOCATIONS CONST0 AND CONST01 ARE PERMANENTLY
 3680 ;TO 0 AND 1 RESPECTIVELY
 3690 CODE0F LDX #CONST0 
 3700        .BYTE $2C 
 3710 CODE29 LDX #CONST1
 3720        TAY ;2ND BYTE OF INSTR TO Y 
 3730 COPY16 LDA $00,X
 3740        STA $0000,Y
 3750        LDA $01,X
 3760        STA $0001,Y
 3770 JL11CF JMP L11CF ;EXECUTE NEXT INSTRUCTION
 3780 ;
 3790 ;OPCODE $1A
 3800 ;P-CODE JUMP INSTRUCTION ;REPRESENTED IN THE CODE
 3810 ;ITSELF AS JUMP ADDRESS MINUS START OF ASSEMBLER 
 3820 ;$E800, IN THE FORMAT OF HIGH BYTE FOLLOWED BY LO
 3830 L029C  TAX 
 3840        DEY 
 3850        LDA (IP),Y
 3860        CMP #$FA
 3870        BCC LITAD
 3880        TAY 
 3890        LDX ADRLO-$FA,Y
 3900        LDA ADRHI-$FA,Y
 3910 SCONST = OFFSET/256-1
 3920 LITAD  SBC #SCONST
 3930 LSTAD  JMP L11CA
 3940 ADRLO  .BYTE L08B7,L0CDC,L0D11
 3950        .BYTE L0620,L08E6,LINOUT
 3960 ADRHI  .BYTE L08B7/256+SCONST
 3970        .BYTE L0CDC/256+SCONST
 3980        .BYTE L0D11/256+SCONST
 3990        .BYTE L0620/256+SCONST
 4000        .BYTE L08E6/256+SCONST
 4010        .BYTE LINOUT/256+SCONST
 4020 ;
 4030 ;OPCODE $15 - INSTRUCTION LENGTH = 1
 4040 ;RETURN TO EXECUTING 6502 MACHINE CODE
 4050 ;X=0, Y=1 AND C=1
 4060 EX6502 INC IP
 4070        BNE L02EA
 4080        INC IP+1
 4090 L02EA  JMP (IP)
 4100 ;
 4110 ;OPCODE $22 XX
 4120 ;MOVE SINGLE BYTE POINTED TO BY 00/01
 4130 ;TO LOCATION POINTED TO BY XX/XX+1
 4140 L04AF  TAX 
 4150        DEY 
 4160        LDA ($00),Y
 4170        STA ($00,X)
 4180 ;ALWAYS BRANCHES - ADVANCE
 4190 ;INTERPRETIVE POINTER AND CONTINUE
 4200        BCS JL11CF
 4210 ;
 4220 ;OPCODE $10 XX BB 
 4230 ;INPUT A 16-BIT DECIMAL NUMBER INTO XX/XX+1
 4240 ;WITH BB BEING A BRANCH OFFSET IN CASE OF OVERFLO
 4250 ;(I.E. RESULT > 65535).  THE TEXT FOR THE NUMBER
 4260 ;ITSELF STARTS AT LOCATION POINTED TO BY $06-$07,
 4270 ;AND $08 CONTAINS THE NUMBER OF DIGITS.  ALL THE
 4280 ;DIGITS HAVE BEEN CONFIRMED TO BE DECIMAL DIGITS
 4290 ;ALREADY.  THE ASSEMBLER ITSELF DOES NOT USE THIS
 4300 ;OPCODE ;IT IS ONLY USED BY THE LINE EDITOR.
 4310 L0300  STX $26
 4320        STX $EC
 4330        TAX 
 4340        LDA #$00
 4350        STA $00,X
 4360        STA $01,X
 4370 L030D  LDY $26
 4380        LDA ($06),Y
 4390        AND #$0F
 4400        STA TMPLOC+1
 4410        TXA 
 4420        TAY 
 4430        LDA #CNST10
 4440        JSR L0A84
 4450        BNE L0327 ;BRANCH IF OVERFLOW
 4460        INC $26
 4470        DEC $08
 4480        BNE L030D
 4490 L3980  BEQ JL11CF ;ADVANCE IP AND EXECUTE
 4500 ;
 4510 ;OPCODE $1C XX BB
 4520 ;REMOVE ERROR NUMBER AND TEXT POINTER FROM STACK 
 4530 ;BRANCH BB IS TAKEN IF STACK IS EMPTY
 4540 L0BC5  TAY 
 4550        STX $01,Y
 4560        LDX NUMERR
 4570        BEQ L0327
 4580        LDA ERRMSG+1,X
 4590        STA $06
 4600        LDA ERRMSG-1,X
 4610        STA $0000,Y
 4620        DEC NUMERR
 4630        BPL JL11CF ;ALWAYS BRANCHES
 4640 ;BRANCH, USING 3RD BYTE OF INSTR
 4650 L0327  LDY #$02
 4660        JMP L0284
 4670 ;PRINT NEW LINE
 4680 NEWLIN LDA #$0D
 4690 L033E  JSR COUT ;PRINT CHARACTER IN ACC
 4700 L0341  LDA #$0A
 4710 ;PRINT CHARACTER IN ACCUMULATOR
 4720 CHROUT JMP COUT 
 4730 ;OPCODE $1F - INSTRUCTION LENGTH VARIABLE
 4740 L03EC  INC $06
 4750        JSR L0341
 4760 ;
 4770 ;OPCODE $1D - INSTRUCTION LENGTH VARIABLE
 4780 ;PRINT POINTER TO ERROR IN LINE OF TEXT, PLUS
 4790 ;ERROR MESSAGE.  START BY PRINTING LINE OF DASHES
 4800 ;UP TO CURRENT POINT IN TEXT.
 4810 L0363  ;CARRY SET BY DEFAULT
 4820        LDA $06
 4830        SBC $02
 4840        BEQ L0373
 4850        TAX 
 4860        LDA #$2D
 4870 L036D  JSR COUT ;PRINT CHARACTER IN ACC
 4880        DEX 
 4890        BNE L036D
 4900 ;PRINT UP-ARROW
 4910 L0373  LDA #$5E
 4920        JSR COUT ;PRINT CHARACTER IN ACC
 4930 ;PRINT CARRIAGE RETURN
 4940        LDA #$0D
 4950        JSR COUT ;PRINT CHARACTER IN ACC
 4960 ;OPCODE $1E - INSTRUCTION LENGTH VARIABLE
 4970 ;PRINT MESSAGE, TERMINATED WITH $00, BUT PRINT
 4980 ;LINE FEED FIRST.
 4990 L037D  JSR L0341
 5000 ;
 5010 ;OPCODE $24 - INSTRUCTION LENGTH VARIABLE
 5020 ;PRINT MESSAGE, TERMINATED WITH #$00 OR #$0D (CR)
 5030 L0380  LDA (IP),Y
 5040        INY 
 5050        TAX ;CHECK FOR END OF MESSAGE
 5060        BEQ L0391
 5070        JSR COUT ;PRINT CHARACTER IN ACC
 5080        CMP #$0D
 5090        BNE L0380
 5100        JSR L0341 
 5110 L0391  JMP L02A9 
 5120 ;
 5130 ;OPCODE $0B - 0B XX YY BB
 5140 ;THIS WORKS FOR OPCODES 0B, 2B, 4B, 6B, 8B, AB,
 5150 ;CB AND EB, ALTHOUGH 0B AND EB NEVER OCCUR. 
 5160 ;COMPARES 16-BIT QUANTITIES IN ZERO PAGE AT
 5170 ;LOCATIONS XX/XX+1 AND .BYTE SET1,/.BYTE SET1,+1,
 5180 ;ON BB IF APPROPRIATE
 5190 ;2B:  BRANCHES IF XX > YY
 5200 ;4B:  BRANCHES IF XX = YY
 5210 ;6B:  BRANCHES IF XX >= YY
 5220 ;8B:  BRANCHES IF XX < YY
 5230 ;AB:  BRANCHES IF XX <> YY
 5240 ;CB:  BRANCHES IF XX <= YY
 5250 L03A0  JSR L04A0
 5260 ;CARRY SET IMPLICITLY 
 5270        LDA $00,X
 5280        SBC $0000,Y
 5290        STA $E5
 5300        LDA $01,X
 5310        SBC $0001,Y
 5320        ORA $E5
 5330        BEQ L03C4
 5340        LDA #%01100000 
 5350        BCS L03C4
 5360        ASL A ;A = $C0
 5370 L03C4  EOR #%01000000 
 5380        LDY #$00
 5390        AND (IP),Y
 5400 L4820  BEQ L3980 ;EXECUTE NEXT INSTRUCTION
 5410 L03CE  LDY #$03
 5420        JMP L0284 ;EXECUTE RELATIVE BRANCH
 5430 ;
 5440 ;OPCODE $20 - 20 XX YY ZZ
 5450 ;SUBTRACT 16-BIT QUANTITY IN YY FROM XX
 5460 ;AND PUT RESULT IN ZZ 
 5470 L0419  DEX ;FLAG = $FF TO SUBTRACT
 5480        .BYTE $24 ;KEEP CARRY SET
 5490 ;
 5500 ;OPCODE $21 - 21 XX YY ZZ
 5510 ;ADD TOGETHER 16-BIT QUANTITIES AT XX AND .BYTE S
 5520 ;PUT RESULT IN ZZ
 5530 L0400  CLC 
 5540        STX $E4
 5550        JSR L04A0
 5560        LDA $0000,Y
 5570        EOR $E4
 5580        ADC $00,X
 5590        PHA 
 5600        LDA $0001,Y
 5610        EOR $E4
 5620        ADC $01,X
 5630        PHA 
 5640        LDY #$03
 5650        LDA (IP),Y
 5660        TAX 
 5670        PLA 
 5680        JMP PULLZP
 5690 ;
 5700 ;OPCODE $0C - INSTRUCTION LENGTH = 1 
 5710 ;COMPRESS LINE OF ASSEMBLER SOURCE CODE
 5720 L0440  STX $28
 5730        STX $0E
 5740        STX $27
 5750 L0446  STX $26
 5760 L0448  LDY $28
 5770        LDA ($00),Y
 5780        CMP $27
 5790        BNE L0456
 5800        DEC $26
 5810        INC $28
 5820        BNE L0448
 5830 L0456  TAX 
 5840        LDY $0E
 5850        LDA $26
 5860        BEQ L0460
 5870        STA ($00),Y
 5880        INY 
 5890 L0460  TXA 
 5900        STA ($00),Y
 5910        STA $27
 5920        INC $28
 5930        INY 
 5940        STY $0E
 5950        LDX #$00
 5960        CMP #$0D
 5970        BNE L0446
 5980        STX $0F
 5990        BEQ L4820 ;ALWAYS BRANCHES
 6000 ;
 6010 ;CALLED BY BLOCK MOVE SUBROUTINE
 6020 ;RETURN WITH Z FLAG SET IF TRANSFERRED
 6030 ;LAST BYTE OF BLOCK
 6040 L03F2  LDA ($26),Y
 6050        STA ($28),Y
 6060        INC $FE
 6070        BNE L03F6
 6080        INC $FF
 6090 L03F6  RTS 
 6100 ;
 6110 ;**************************************
 6120 ;THE FOLLOWING DECLARATIONS PRECEDE THE
 6130 ;FIRST PIECE OF PSEUDOCODE
 6140 ;**************************************
 6150 OFS=*/256*256
 6160 OFFSET = $E800-OFS
 6170 ;
 6180 ;OPCODE $00 - INSTRUCTION LENGTH = 2
 6190 ;STEP ON TO NEXT LINE OF SOURCE FILE -
 6200 ;PUT LOCATION IN TXTPOS, AND
 6210 ;PUT LENGTH IN LINLEN
 6220 ;PUT LINE NUMBER IN $38
 6230 ;TAKE RELATIVE BRANCH IN 2ND BYTE IF END
 6240 L047C  .BYTE ADDZ,TXTPOS,LINLEN,TXTPOS
 6250        .BYTE ADDZ,LINENO,CONST1,LINENO
 6260        .BYTE SET0,LINLEN
 6270        .BYTE BNEQ,TXTPOS,ENDTXT,L048E-*
 6280        .BYTE RET2 ;RETURN - 2ND BYTE OF CALL IS BR
 6290 ;
 6300 ;OPCODE $02 - INSTRUCTION LENGTH = 1 
 6310 ;FETCH FIRST LINE OF SOURCE FILE -
 6320 ;PUT LOCATION IN TXTPOS, AND
 6330 ;PUT LENGTH IN LINLEN
 6340 ;PUT LINE NUMBER IN $38
 6350 L03D4  .BYTE COPY,STTEXT,TXTPOS
 6360        .BYTE BEQU,TXTPOS,ENDTXT,L04E6-* ;RET
 6370 L048E  .BYTE BMOV,CONST2,TXTPOS,$38
 6380 ;AND PUT LENGTH OF LINE IN LINLEN
 6390        .BYTE EX65
 6400 ;SKIP OVER 2 BYTES LINE NUMBER
 6410 L0493  INY 
 6420        LDA (TXTPOS),Y
 6430        CMP #$0D
 6440        BNE L0493
 6450        INY 
 6460        STY LINLEN
 6470        JMP L02BC ;RETURN FROM P-CODE SUBROUTINE
 6480 ;GET NEXT ARGUMENT IN LIST.
 6490 ;LOOK AT NEXT ARGUMENT FOR P-CODE INSTRUCTION.
 6500 ;IF THAT ARGUMENT IS NEGATIVE, USE IT TO INDEX
 6510 ;CALLING INSTRUCTION.
 6520 L04A0  LDA (IP),Y
 6530        BPL L04AD
 6540        AND #$7F
 6550        TAY 
 6560        LDA (CALADR),Y
 6570 L04AD  TAX 
 6580        LDY #$02
 6590        LDA (IP),Y
 6600        TAY 
 6610        RTS 
 6620 ;
 6630 ;OPCODE $01 XX YY, ZZ - MEMORY BLOCK MOVE
 6640 ;XX IS LENGTH OF BLOCK (IN $46/$47)
 6650 ;YY IS START OF SOURCE (IN $26/$27)
 6660 ;ZZ IS START OF DESTINATION (IN $28/$29)
 6670 L04C0  .BYTE COPY,$81,$46 ;STORE LENGTH
 6680 ;EXIT IF LENGTH IS ZERO
 6690        .BYTE BEQU,$46,CONST0,L04E6-* 
 6700        .BYTE SUBZ,CONST0,$46,$FE
 6710        .BYTE COPY,$82,$26 ;STORE SOURCE
 6720        .BYTE COPY,$83,$28 ;STORE DESTINATION
 6730 ;BRANCH IF DESTINATION HIGHER THAN SOURCE
 6740        .BYTE BLES,$26,$28,L04E7-* 
 6750 ;SOURCE ADDRESS HIGHER THAN DEST ADDRESS
 6760 ;START BLOCK MOVE FROM LOWEST ADDRESS
 6770        .BYTE EX65
 6780        DEY 
 6790        BEQ L04DE ;ALWAYS BRANCHES
 6800 L04D7  INY 
 6810        BNE L04DE
 6820        INC $27
 6830        INC $29
 6840 L04DE  JSR L03F2
 6850        BNE L04D7
 6860 L04E3  JSR L11DC ;EXECUTE P-CODE
 6870 L04E6  .BYTE RETN
 6880 ;DEST ADDRESS HIGHER THAN SOURCE ADDRESS
 6890 ;START BLOCK MOVE FROM HIGHEST ADDRESS
 6900 L04E7  .BYTE EX65
 6910        CLC 
 6920        LDA $47
 6930        ADC $27
 6940        STA $27
 6950        LDA $47
 6960        ADC $29
 6970        STA $29
 6980        LDY $46
 6990 L04F1  TYA 
 7000        BNE L04F8
 7010        DEC $27
 7020        DEC $29
 7030 L04F8  DEY 
 7040        JSR L03F2
 7050        BNE L04F1
 7060        BEQ L04E3
 7070 ;
 7080 ;OPCODE $1B - INSTRUCTION LENGTH = 2
 7090 ;PRINT LINE POINTED TO BY LOCATION XX/XX+1
 7100 ;CARRIES OUT DECOMPRESSION OF TEXT
 7110 L0500  TAX 
 7120        LDA $00,X
 7130        STA $26
 7140        LDA $01,X
 7150        STA $27
 7160        DEY 
 7170 L050C  LDX #$FF
 7180        LDA ($26),Y
 7190        BPL L0515
 7200        TAX 
 7210        LDA $28
 7220 L0515  JSR COUT ;PRINT CHARACTER IN ACC
 7230        INX 
 7240        BMI L0515
 7250        STA $28
 7260        INY 
 7270        CMP #$0D
 7280        BNE L050C
 7290        LDA #$00
 7300        JSR L033E
 7310 L6610  JMP L11CF ;ADVANCE INTERPRETIVE POINTER AND
 7320 ;OPCODE 19 XX
 7330 ;PRINT DIGIT DECIMAL NUMBER IN LOCATIONS XX
 7340 ;AND XX+1, RIGHT-JUSTIFIED IN A FIELD OF 5
 7350 ;CHARACTERS
 7360 L0590  TAX 
 7370        LDA $00,X
 7380        STA $26
 7390        LDA $01,X
 7400        STA $27
 7410        LDA #$05
 7420        STA $46
 7430        LDX #$26
 7440        LDY #CNST10
 7450        LDA #$28
 7460 L05A5  JSR L052A
 7470        STA $47
 7480        LDA $00,X
 7490        PHA 
 7500        TXA 
 7510        LDX $47
 7520        DEC $46
 7530        BNE L05A5
 7540        LDX #$80
 7550 L05B6  PLA 
 7560        BEQ L05BE
 7570        TAX 
 7580        ORA #$30
 7590        BNE L05C5
 7600 L05BE  ORA #$30
 7610        INX 
 7620        BPL L05C5
 7630        LDA #$20
 7640 L05C5  JSR COUT ;PRINT CHARACTER IN ACC
 7650        INC $46
 7660        LDA $46
 7670        CMP #$05
 7680        BNE L05B6
 7690        BEQ L6610 ;ADVANCE INTERPRETIVE POINTER AND
 7700 ;DIVISION SUBROUTINE:
 7710 ;(A) = (X) / (Y)
 7720 L052A  STA $E4
 7730        STX $E5
 7740        STY TMPLOC
 7750        LDX TMPLOC
 7760        LDY #$01
 7770        LDA $01
 7780        BMI L0543
 7790 L0538  INY 
 7800        ASL $00,X
 7810        ROL $01,X
 7820        BMI L0543
 7830        CPY #$11
 7840        BNE L0538
 7850 L0543  STY TMPLOC+1
 7860        LDY $E4
 7870        LDX #$00
 7880        STX $00,Y
 7890        STX $01,Y
 7900        LDY TMPLOC
 7910 L054F  LDX $E5
 7920        SEC 
 7930        LDA $00,X
 7940        SBC $0000,Y
 7950        STA $EC
 7960        LDA $01,X
 7970        SBC $0001,Y
 7980        BCC L0566
 7990        STA $01,X
 8000        LDA $EC
 8010        STA $00,X
 8020 L0566  LDX $E4
 8030        ROL $00,X
 8040        ROL $01,X
 8050        DEC TMPLOC+1
 8060        BEQ L0583
 8070        LDX TMPLOC
 8080        LSR $01,X
 8090        ROR $00,X
 8100        SEC 
 8110        BCS L054F
 8120 L0583  LDA $E4
 8130        LDX $E5
 8140        RTS 
 8150 ;'R' COMMAND
 8160 L066C  .BYTE COPY,CNST10,$36
 8170        .BYTE LIN1
 8180 L0831  .BYTE BEQU,TXTPOS,ENDTXT,L0842-*
 8190        .BYTE BMOV,CONST2,$3A,TXTPOS
 8200        .BYTE ADDZ,CNST10,$36,$36
 8210        .BYTE NXLN,L0842-*
 8220        .DBYTE L0831+OFFSET
 8230 L0842  .BYTE MSLN,$00
 8240        .BYTE LIN1
 8250        .BYTE PDEC,$36
 8260        .DBYTE PSTART+OFFSET
 8270 ;LINE NUMBER FOUND
 8280 L0663  .DBYTE L0690+OFFSET
 8290 ;'P' COMMAND
 8300 L0666  .DBYTE L0750+OFFSET
 8310 ;'D' COMMAND
 8320 L0669  .DBYTE L07D0+OFFSET
 8330 ;***********************************
 8340 ;ENTRY POINT FOR P-CODE UPON STARTUP
 8350 PINIT  .BYTE COPY,STTEXT,TXTPOS
 8360 PSTART .BYTE MESG,$0D ;PRINT NEW LINE
 8370 ;************************************
 8380 L0601  .BYTE CLAS,L0663-*,L0605-*,L0620-* 
 8390 L0605  .BYTE CHK6+'A,L0660-* ;TEST FOR 'A' COMMAN
 8400        .BYTE CHK6+'P,L0666-* ;TEST FOR 'P' COMMAN
 8410        .BYTE CHK6+'I,LICMD-* ;TEST FOR 'I' COMMAN
 8420        .BYTE CHK6+'D,L0669-* ;TEST FOR 'D' COMMAN
 8430        .BYTE CHK6+'R,L066C-* ;TEST FOR 'R' COMMAN
 8440 L0614  .BYTE CHK6+'S,L130C-* ;'S' COMMAND
 8450        .BYTE CHK6+'L,L1316-* ;'L' COMMAND
 8460 CMDERR .BYTE PER6,'CMD ERR',$0D 
 8470 L0620  .BYTE MSLN,'.',$00 ;PRINT FULL STOP
 8480        .BYTE KBLN ;GET LINE OF KEYBOARD INPUT 
 8490        .DBYTE L0601+OFFSET
 8500 ;
 8510 ;'S' AND 'L' COMMANDS FOR UK101 VERSION
 8520 ;'S' COMMAND
 8530 L130C  .BYTE EX65 ;EXECUTE 6502 MACHINE CODE
 8540        JSR SAVE ;TURN ON SAVE FLAG
 8550        JMP L1310
 8560 ;'L' COMMAND
 8570 L1316  .BYTE EX65 ;EXECUTE 6502 MACHINE CODE
 8580        JSR LOAD
 8590 L1310  JSR L11DC ;RETURN TO P-CODE
 8600        .BYTE $FD ;JMP TO L0620
 8610 ;'A' COMMAND
 8620 L0660  .BYTE MSLN,$0D
 8630        .BYTE BEQU,STTEXT,ENDTXT,L0620-*
 8640        .BYTE SET1,ASMBRK
 8650        .BYTE SET0,ASMOPT
 8660        .BYTE SET0,A2BLEN-1 ;SET NO. BYTES FOR A2 T
 8670        .BYTE CLAS,L112A-*,CMDERR-*,L112D-*
 8680        .DBYTE CMDERR+OFFSET
 8690 L112A  .BYTE DCIN,ASMOPT,CMDERR-*
 8700 L112D  .DBYTE L0850+OFFSET
 8710 ;
 8720 ;OPCODE $03 XX YY ZZ
 8730 ;XX IS RELATIVE BRANCH FOR DECIMAL NUMBER
 8740 ;YY IS RELATIVE BRANCH FOR NOT DECIMAL
 8750 ;NUMBER, NOT CAPITAL LETTER, AND NOT
 8760 ;END OF LINE
 8770 ;ZZ IS RELATIVE BRANCH FOR END OF LINE
 8780 ;NO BRANCH TAKEN IF CAPITAL LETTER
 8790 L0626  .BYTE COPY,$00,$04 ;COPY POINTER
 8800        .BYTE DECR,$00 ;DECREMENT POINTER AT $00/$0
 8810 L062B  .BYTE INC0 ;INC POINTER AT $00/$01
 8820        .BYTE CHK0+$20,L062B-* ;SKIP SPACES
 8830        .BYTE SET0,$08 ;SET CHAR CHOUNT TO ZERO 
 8840        .BYTE COPY,$00,$06 ;COPY POINTER TO $06/$07
 8850        .BYTE CHK0+CAP,L0649-* ;BRANCH IF CAPITAL
 8860        .BYTE CHK0+DCM,L0651-* ;BRANCH IF DECIMAL
 8870        .BYTE CHK0+$0D,L065A-* ;BRANCH IF END OF L
 8880        .BYTE COPY,$00,$06 ;COPY POINTER TO $06/$07
 8890 ;THE FOLLOWING LINE IS ALMOST CERTAINLY ANOMOLOUS
 8900 ;SO IT HAS BEEN COMMENTED OUT. 
 8910 ;.BYTE COPY,PRFLAG,$08 ;COPY FROM $F0/$F1 TO $08/$
 8920        .BYTE INC0 ;INCREMENT POINTER AT $00/$01
 8930        .BYTE RET3 ;RETURN - 3RD BYTE OF CALL IS OF
 8940 ;CAPITAL LETTER FOUND
 8950 L0649  .BYTE INC0
 8960        .BYTE INCR,$08
 8970        .BYTE CHK0+CAP,L0649-*
 8980        .BYTE RETN
 8990 ;DECIMAL DIGIT FOUND
 9000 L0651  .BYTE INC0
 9010        .BYTE INCR,$08
 9020        .BYTE CHK0+DCM,L0651-*
 9030        .BYTE RET2 ;2ND BYTE OF CALL IS OFFSET
 9040 ;END OF LINE FOUND
 9050 L065A  .BYTE RET4 ;4TH BYTE OF CALL IS OFFSET
 9060 ;'I' COMMAND
 9070 LICMD  .BYTE MSLN,'INIZ?',$00
 9080        .BYTE KBLN ;GET LINE OF KEYBOARD INPUT
 9090        .BYTE COPY,STTEXT,$10
 9100        .BYTE SET0,LINLEN
 9110        .BYTE CHK0+'Y,L068A-*
 9120        .BYTE $FD ;JMP TO L0620
 9130 L068A  .BYTE COPY,STTEXT,ENDTXT
 9140        .BYTE $FD ;JMP TO L0620
 9150 ;****************************
 9160 ;LINE NUMBER FOUND ON COMMAND LINE.
 9170 ;INPUT DECIMAL NUMBER TO $36/$37.
 9180 ;GO TO L06F3 IF TOO BIG.
 9190 L0690  .BYTE DCIN,$36,L06F3-* 
 9200        .BYTE COMP ;COMPRESS REST OF LINE
 9210        .BYTE ADDZ,$0E,CONST2,$0E
 9220        .BYTE BEQU,$36,CONST0,L06B1-*
 9230        .BYTE BGEQ,$36,LINENO,L06A3-*
 9240        .BYTE LIN1
 9250 L06A3  .BYTE BGEQ,LINENO,$36,L06AC-*
 9260        .BYTE NXLN,L06B1-*
 9270        .DBYTE L06A3+OFFSET
 9280 L06AC  .BYTE BEQU,LINENO,$36,L06B4-*
 9290 L06B1  .BYTE SET0,LINLEN
 9300 L06B4  .BYTE ADDZ,TXTPOS,$0E,$1C
 9310        .BYTE ADDZ,TXTPOS,LINLEN,DRTYPE
 9320        .BYTE SUBZ,ENDTXT,DRTYPE,$20
 9330        .BYTE ADDZ,$1C,$20,$22
 9340        .BYTE BRGR,$22,ENDMEM,L06EA-*
 9350        .BYTE BMOV,$20,DRTYPE,$1C
 9360        .BYTE SUBZ,$0E,CONST2,$1C
 9370        .BYTE ADDZ,TXTPOS,CONST2,DRTYPE
 9380        .BYTE BMOV,$1C,$00,DRTYPE
 9390        .BYTE BEQU,$36,CONST0,L05DB-*
 9400        .BYTE COPY,$36,LINENO
 9410 L05DB  .BYTE BMOV,CONST2,$3A,TXTPOS
 9420        .BYTE COPY,$0E,LINLEN
 9430        .BYTE COPY,$22,ENDTXT
 9440        .BYTE NXLN,L06E8-*
 9450 L06E8  .BYTE $FD ;JMP TO L0620
 9460 L06EA  .BYTE MSLN,'*FULL',$0D
 9470        .BYTE $FD ;JMP TO L0620
 9480 L06F3  .BYTE PER6,'#TOO BIG',$0D
 9490        .BYTE $FD ;JMP TO L0620
 9500 ;
 9510 ;OPCODE $04 - INSTRUCTION LENGTH = 2
 9520 ;SECOND BYTE IS AN OFFSET
 9530 L0700  .BYTE SET0,$1C
 9540        .BYTE COPY,$2E,DRTYPE
 9550        .BYTE CLAS,L070C-*,L071C-*,L074E-* 
 9560        .BYTE COPY,$04,$00
 9570        .BYTE RET2 ;2ND BYTE OF CALL IS BRANCH
 9580 L070C  .BYTE DCIN,$1C,L0741-*
 9590        .BYTE CLAS,L073B-*,L0721-*,L0718-* 
 9600        .BYTE COPY,$1C,DRTYPE ;COPY $1C/$1D INTO D
 9610 L0716  .BYTE COPY,$04,$00
 9620 L0717  .BYTE RETN
 9630 L0718  .BYTE COPY,$1C,DRTYPE
 9640        .BYTE RETN
 9650 L071C  .BYTE CHK6+'-,L0729-*
 9660        .DBYTE L073B+OFFSET
 9670 L0721  .BYTE CHK6+'-,L0729-* ;GO TO L0729 IF DAS
 9680        .BYTE CHK6+',,L0718-* ;GO TO L0718 IF COM
 9690        .DBYTE L073B+OFFSET
 9700 L0729  .BYTE CLAS,L072F-*,L0738-*,L0717-*
 9710        .DBYTE L0716+OFFSET
 9720 L072F  .BYTE DCIN,DRTYPE,L0741-* ;READ DECIMAL N
 9730        .BYTE CLAS,L073B-*,L0738-*,L0717-*
 9740        .DBYTE L0716+OFFSET
 9750 L0738  .BYTE CHK6+',,L0717-*
 9760 L073B  .BYTE PER6,'??',$0D
 9770        .BYTE RET2
 9780 L0741  .BYTE PER6,'#TOO BIG',$0D
 9790 L074E  .BYTE RET2 ;2ND BYTE OF CALL IS BRANCH
 9800 ;'P' COMMAND
 9810 L0750  .BYTE LRAN,L0752-*
 9820 L0752  .BYTE MSLN,$0D
 9830 L0754  .BYTE LIN1
 9840        .BYTE BEQU,TXTPOS,ENDTXT,L0778-*
 9850 L075A  .BYTE BGEQ,LINENO,$1C,L0763-*
 9860        .BYTE NXLN,L0768-*
 9870        .DBYTE L075A+OFFSET
 9880 L0763  .BYTE BLEQ,LINENO,DRTYPE,L076C-*
 9890 L0768  .BYTE LRAN,L0778-*
 9900        .DBYTE L0754+OFFSET
 9910 L076C  .BYTE PDEC,LINENO
 9920        .BYTE ADDZ,TXTPOS,CONST2,$20
 9930        .BYTE PLIN,$20 
 9940        .BYTE NXLN,L0768-*
 9950        .DBYTE L0763+OFFSET
 9960 LEN1=$1000-OF6502
 9970 LEN2=$2000-OF6502
 9980 LEN3=$3000-OF6502
 9990 LEN4=$4000-OF6502
10000 LENF=$F000-OF6502
10010 OP00=L047C+LEN2
10020 OP01=L04C0+LEN4
10030 OP02=L03D4+LEN1
10040 OP03=L0626+LEN4
10050 OP04=L0700+LEN2
10060 OP05=L0961+LEN1
10070 OP06=L0989+LEN4
10080 OP07=L0985+LEN4
10090 OP08=L10B3+LEN1
10100 OP09=L0C30+LEN2
10110 OP0A=L0AF0+LEN2
10120 OP0B=L03A0+LEN4
10130 OP0C=L0440+LEN1
10140 OP0D=L0205+LEN1
10150 OP0E=OP1203+LEN1
10160 OP0F=CODE0F+LEN2
10170 OP10=L0300+LEN3
10180 OP11=L02BC+LEN1
10190 OP12=OP1201+LEN1
10200 OP13=L02D0+LEN2
10210 OP14=L02DC+LEN2
10220 OP15=EX6502+LEN1
10230 OP16=L0270+LEN3
10240 OP17=L0BE5+LEN2
10250 OP18=L0965+LEN2
10260 OP19=L0590+LEN2
10270 OP1A=L029C+LEN3
10280 OP1B=L0500+LEN2
10290 OP1C=L0BC5+LEN3
10300 OP1D=L0363+LENF
10310 OP1E=L037D+LENF
10320 OP1F=L03EC+LENF
10330 OP20=L0419+LEN4
10340 OP21=L0400+LEN4
10350 OP22=L04AF+LEN2
10360 OP23=L0A60+LEN1
10370 OP24=L0380+LENF
10380 OP25=OP1202+LEN1
10390 OP26=L0240+LEN2
10400 OP27=L0244+LEN2
10410 OP28=L11CE+LEN1
10420 OP29=CODE29+LEN2
10430 ;ADDRESSES FOR OPCODE ROUTINES
10440 ;OPCODES ALLOWED ARE 00 TO 27 INCLUSIVE
10450 ;MSB MAY BE SET, INDICATING P-CODE SUBROUTINE
10460 ADDRLO .BYTE OP00,OP01,OP02,OP03
10470        .BYTE OP04,OP05,OP06,OP07
10480        .BYTE OP08,OP09,OP0A,OP0B
10490        .BYTE OP0C,OP0D,OP0E,OP0F
10500        .BYTE OP10,OP11,OP12,OP13
10510        .BYTE OP14,OP15,OP16,OP17
10520        .BYTE OP18,OP19,OP1A,OP1B
10530        .BYTE OP1C,OP1D,OP1E,OP1F
10540        .BYTE OP20,OP21,OP22,OP23
10550        .BYTE OP24,OP25,OP26,OP27
10560        .BYTE OP28,OP29
10570 ADDRHI .BYTE OP00/256,OP01/256
10580        .BYTE OP02/256,OP03/256
10590        .BYTE OP04/256,OP05/256
10600        .BYTE OP06/256,OP07/256
10610        .BYTE OP08/256,OP09/256
10620        .BYTE OP0A/256,OP0B/256
10630        .BYTE OP0C/256,OP0D/256
10640        .BYTE OP0E/256,OP0F/256
10650        .BYTE OP10/256,OP11/256
10660        .BYTE OP12/256,OP13/256
10670        .BYTE OP14/256,OP15/256
10680        .BYTE OP16/256,OP17/256
10690        .BYTE OP18/256,OP19/256
10700        .BYTE OP1A/256,OP1B/256
10710        .BYTE OP1C/256,OP1D/256
10720        .BYTE OP1E/256,OP1F/256
10730        .BYTE OP20/256,OP21/256
10740        .BYTE OP22/256,OP23/256
10750        .BYTE OP24/256,OP25/256
10760        .BYTE OP26/256,OP27/256
10770        .BYTE OP28/256,OP29/256
10780 L0778  .DBYTE L0601+OFFSET
10790 L07D0  .BYTE LRAN,L0807-*
10800 L07D2  .BYTE SET0,$22
10810        .BYTE LIN1
10820 L07DB  .BYTE BGEQ,LINENO,$1C,L07E4-*
10830        .BYTE NXLN,L0811-*
10840        .DBYTE L07DB+OFFSET
10850 L07E4  .BYTE COPY,TXTPOS,$1C
10860 L07E7  .BYTE BRGR,LINENO,DRTYPE,L07F0-*
10870        .BYTE INCR,$22
10880        .BYTE ADDZ,TXTPOS,LINLEN,$20
10890        .BYTE NXLN,L07F0-*
10900        .DBYTE L07E7+OFFSET
10910 L07F0  .BYTE SUBZ,ENDTXT,$20,DRTYPE
10920        .BYTE BEQU,$22,CONST0,L0811-*
10930        .BYTE BMOV,DRTYPE,$20,$1C
10940        .BYTE ADDZ,$1C,DRTYPE,ENDTXT
10950        .BYTE LIN1
10960        .BYTE LRAN,L0778-*
10970        .DBYTE L07D2+OFFSET
10980 L0807  .BYTE PER6,'LINES?',$0D
10990        .DBYTE L0822+OFFSET
11000 L0811  .BYTE PER6,'NO SUCH LINE(S)',$0D
11010 L0822  .BYTE $FD ;JMP TO L0620
11020 L084A  .BYTE INC0
11030        .BYTE RLBL,L1153-*
11040 ;ERROR 26 - ILLEGAL DIRECTIVE
11050 L114F  .BYTE RERR,$1A
11060        .DBYTE L10A7+OFFSET
11070 L1153  .DBYTE L104E+OFFSET
11080 L084D  .BYTE SET0,INSTLN
11090        .BYTE INC0
11100        .BYTE SKIP ;SKIP SPACES
11110        .BYTE CHK0+'=,L100C-*
11120        .BYTE $FA ;JMP TO L08B7
11130 L100C  .BYTE INC0
11140        .BYTE SKIP ;SKIP SPACES
11150        .BYTE EXPR,L1023-*
11160        .BYTE CHK0+SPC,L1017-*
11170        .BYTE $FE ;JMP TO L08E6
11180 L1017  .BYTE EX65
11190        LDA #$3F 
11200        BIT $ED
11210        BEQ L1025
11220        JSR L11DC ;EXECUTE P-CODE
11230 ;ERROR 4 - FWD REF IN EQUATE DIRECTIVE
11240        .BYTE RERR,$84
11250 L1023  .BYTE $FF ;JMP TO LINOUT
11260 L1025  JSR L11DC ;EXECUTE P-CODE
11270        .BYTE SET1,ASMBRK
11280        .BYTE COPY,NUMVAL,ASMADR
11290        .BYTE $FF ;JMP TO LINOUT
11300 ;
11310 ;'A' COMMAND - ASMOPT HAS ALREADY BEEN
11320 ;SET UP.
11330 L0850  .BYTE SET0,$7C
11340        .BYTE COPY,ENDMEM,LABTBL ;CLEAR LABEL TABL
11350        .BYTE SET1,PASS
11360 ;START NEXT PASS OF ASSEMBLY
11370 NXTPAS .BYTE SET0,ASMADR
11380        .BYTE LIN1 ;GET FIRST LINE OF SOURCE CODE
11390 L085D  .BYTE SET0,PRFLAG ;LINE NOT YET PRINTED
11400        .BYTE SET0,NUMERR ;NO ERRORS SO FAR
11410        .BYTE DCMP ;DECOMPRESS TEXT AT TXTPOS/TXTP
11420        .BYTE COPY,$02,$00 ;MOVE POINTER FOR LINE 
11430 ;SET DEFAULT INSTRUCTION TO 3 NOP BYTES
11440        .BYTE COPY,CONST3,INSTLN
11450        .BYTE COPY,NOPBYT,INSTRN
11460        .BYTE COPY,NOPBYT,INSTRN+2
11470        .BYTE SET0,$54
11480        .BYTE SKIP ;SKIP SPACES
11490        .BYTE CHK0+$0D,L08C6-*
11500        .BYTE CHK0+';,L08AD-*
11510        .BYTE CHK0+'*,L084D-*
11520        .BYTE CHK0+'.,L084A-* ;PROCESS DIRECTIVE
11530        .BYTE RLBL,L0887-*
11540 ;ERROR 9 - LABEL DOESN'T BEGIN WITH LETTER
11550        .BYTE RERR,$09
11560        .BYTE $FF ;JMP TO LINOUT
11570 L0887  .BYTE LVAL,L08AB-*,L08BB-*,L088C-*
11580 L088C  .BYTE SET1,$54
11590        .BYTE CHK0+$20,L0894-*
11600        .DBYTE L089A+OFFSET
11610 L0894  .BYTE SKIP ;SKIP SPACES
11620        .BYTE RLBL,L08B2-*
11630        .BYTE CHK0+'.,L084A-*
11640 L089A  .BYTE CHK0+'*,L084D-*
11650        .BYTE CHK0+'=,L08A8-*
11660        .BYTE CHK0+';,L08AD-*
11670        .BYTE CHK0+$0D,L08AD-*
11680        .BYTE $FA ;JMP TO L08B7
11690 L08A8  .DBYTE L1028+OFFSET
11700 ;ERROR 1 - 'A' IS A RESERVED NAME
11710 L08AB  .BYTE RERR,$01
11720 L08AD  .BYTE SET0,INSTLN
11730        .BYTE $FF ;JMP TO LINOUT
11740 L08B2  .BYTE LEXP,L08B7-*,L08BB-*,L08B7-*
11750 ;ERROR 6 - ILLEGAL OR MISSING OPCODE
11760 L08B7  .BYTE RERR,$06
11770        .BYTE $FF ;JMP TO LINOUT
11780 L08BB  .BYTE CHK0+SPC,L08C0-*
11790        .BYTE $FA ;JMP TO L08B7
11800 L0EBC  .BYTE SET1,INSTLN
11810        .BYTE COPY,$20,INSTRN
11820        .BYTE $FF ;JMP TO LINOUT
11830 L08C0  .BYTE BEQU,DRTYPE,CONST0,L0EBC-*
11840        .BYTE SKIP ;SKIP SPACES
11850 L08C6  .BYTE CHK0+$0D,L090C-*
11860        .BYTE CHK0+'#,IMMADR-*
11870        .BYTE CHK0+'(,INDADR-*
11880        .BYTE COPY,CNST80,$56
11890        .BYTE CHK0+'A,L0950-*
11900 L08D5  .BYTE EXPR,L08F4-*
11910        .BYTE CHK0+',,L0934-*
11920        .BYTE COPY,$5A,$56
11930        .DBYTE L0948+OFFSET
11940 ;
11950 ;PROCESS IMMEDIATE ADDRESSING
11960 IMMADR .BYTE INC0
11970        .BYTE EXPR,L08F4-* ;GET EXPRESSION
11980        .BYTE CHK0+SPC,L08EA-*
11990 ;ERROR 7 - INVALID EXPRESSION
12000 L08E6  .BYTE RERR,$07
12010        .BYTE $FF ;JMP TO LINOUT
12020 L08EA  .BYTE COPY,$5C,$56
12030        .BYTE DECR,INSTLN ;INSTR LEN = 2
12040        .DBYTE L0D3D+OFFSET
12050 L08F4  .BYTE $FF ;JMP TO LINOUT
12060 INDADR .BYTE INC0
12070        .BYTE EXPR,L08F4-*
12080        .BYTE CHK0+',,L0902-*
12090        .BYTE CHK0+'),L0920-*
12100        .BYTE $FE ;JMP TO L08E6
12110 L0902  .BYTE INC0
12120        .BYTE CHK0+'X,L0909-*
12130        .BYTE $FE ;JMP TO L08E6
12140 L0909  .BYTE COPY,$5E,$56
12150        .BYTE INC0
12160        .BYTE CHK0+'),L0910-* 
12170        .BYTE $FE ;JMP TO L08E6
12180 ;ERROR 15 - RAN OFF END OF LINE
12190 L090C  .BYTE RERR,$0F
12200        .BYTE $FF ;JMP TO LINOUT
12210 L0910  .BYTE INC0
12220        .BYTE CHK0+SPC,L0917-*
12230        .BYTE $FE ;JMP TO L08E6
12240 L0917  .BYTE BLES,NUMVAL,CONST1-1,L094D-*
12250 ;ERROR 13 - OUT OF BOUND INDIRECT ADDR
12260        .BYTE RERR,$0D
12270        .BYTE $FF ;JMP TO LINOUT
12280 L0920  .BYTE INC0
12290        .BYTE CHK0+',,L092A-*
12300        .BYTE COPY,$62,$56
12310        .DBYTE L0948+OFFSET
12320 L092A  .BYTE INC0
12330        .BYTE COPY,$60,$56
12340        .BYTE CHK0+'Y,L0910-*
12350        .BYTE $FE ;JMP TO L08E6
12360 L0934  .BYTE INC0
12370        .BYTE COPY,$64,$56
12380        .BYTE CHK0+'X,L0946-*
12390        .BYTE COPY,$66,$56
12400        .BYTE CHK0+'Y,L0946-*
12410 ;ERROR 8 - INVALID INDEX - NOT X OR Y
12420        .BYTE RERR,$08
12430        .BYTE $FF ;JMP TO LINOUT
12440 L0946  .BYTE INC0
12450 L0948  .BYTE CHK0+SPC,L094D-*
12460        .BYTE $FE ;JMP TO L08E6
12470 L094D  .DBYTE L0D3D+OFFSET
12480 L0950  .BYTE INC0
12490        .BYTE CHK0+SPC,L094D-*
12500        .BYTE DECR,$00
12510        .DBYTE L08D5+OFFSET
12520 ;
12530 ;OPCODE $05 - INSTRUCTION LENGTH = 1
12540 ;SKIP SPACES IN INPUT STREAM
12550 ;ENTRY POINT IS AT L0961
12560 L095F  .BYTE INC0 ;INCREMENT CHARACTER POINTER
12570 L0961  .BYTE CHK0+$20,L095F-*
12580        .BYTE RETN
12590 ;
12600 ;OPCODE $18 XX
12610 ;TAKE RECORD OF ERROR NO XX PLUS TEXT POINTER ;
12620 ;A MAXIMUM OF TWO SUCH RECORDS CAN BE KEPT
12630 L0965  LDX NUMERR 
12640        CPX #2
12650        BEQ L0982
12660        ASL A 
12670        LDY PASS
12680        DEY 
12690        BNE L0975
12700        BCC L0982
12710 L0975  LSR A 
12720        STA ERRMSG,X
12730        LDA $00
12740        STA ERRMSG+2,X
12750        INC NUMERR
12760 L0982  JMP L11CF ;ADVANCE INTERPRETIVE POINTER AN
12770 ;
12780 ;ENTRY FOUND IN TABLE
12790 L0A20  TXA 
12800        LSR A
12810        TAY 
12820        LDA INSTYP,Y
12830        BCS NOLSR
12840        LSR A
12850        LSR A
12860        LSR A
12870        LSR A
12880 NOLSR  AND #$0F
12890        TAY 
12900        CPY #$0F
12910        BNE L0A2D ;BRANCH IF OPCODE MNEMONIC
12920        JSR L11DC ;EXECUTE P-CODE
12930        .BYTE RET2 ;2ND BYTE OF CALL IS BRANCH
12940 ;OPCODE MNEMONIC FOUND
12950 ;LOAD DRTYPE ACCORDING TO INSTR TYPE
12960 L0A2D  LDA L0DD5,Y
12970        STA DRTYPE
12980        LDA L0DE3,Y
12990        STA DRTYPE+1
13000        LDA INSBAS-2,X ;GET OPCODE BASE
13010        STA $20
13020        JSR L11DC ;EXECUTE P-CODE
13030        .BYTE RET3 ;3RD BYTE OF CALL IS BRANCH
13040 ;
13050 ;OPCODE $07 - INSTRUCTION LENGTH = 5
13060 ;SEARCH FOR LABEL, AS PART OF EXPRESSION
13070 ;BYTES 2, 3, AND 4 ARE RELATIVE BRANCH OFFSETS
13080 ;NO BRANCH:  LABEL FOUND ;VALUE IN LABVAL
13090 ;BYTE 2:  A, X, Y, S, OR P HAS BEEN FOUND
13100 ;BYTE 3:  OPCODE MNEMONIC FOUND
13110 ;BYTE 4:  UNDEFINED LABEL
13120 L0985  .BYTE EX65
13130        DEY 
13140        .BYTE $24
13150 ;
13160 ;OPCODE $06 - INSTRUCTION LENGTH = 5
13170 ;SEARCH FOR LABEL, AS L-VALUE
13180 ;BYTES 2, 3, AND 4 ARE RELATIVE BRANCH OFFSETS
13190 ;NO BRANCH:  LABEL FOUND ;VALUE IN LABVAL
13200 ;BYTE 2:  A, X, Y, S, OR P HAS BEEN FOUND
13210 ;BYTE 3:  OPCODE MNEMONIC FOUND
13220 ;BYTE 4:  UNDEFINED LABEL
13230 L0989  .BYTE EX65
13240        STY $30 ;1 FOR INSTRUCTION $06 AND 0 FOR $
13250        STX $32 ;ASSUME LABEL DEFINED BY DEFAULT
13260 ;LABEL IS STORED IN 4 BYTES STARTING AT LABL40
13270        LDA LABL40+2
13280        ORA LABL40+3
13290        BNE L09B9 ;BRANCH IF LABEL 4 CHARS OR LONG
13300 ;USE BINARY SEARCH TO FIND OPCODE
13310 ;RECORDS ARE 4 BYTES EACH
13320 ;TABLE HAS 63 RECORDS, ALTHOUGH NOT ALL ARE
13330 ;PRESENT IN MNEMLO, INSBAS AND INSTYP.
13340 ;$E4 CONTAINS CURRENT CHOP SIZE
13350        LDA #$20
13360        STA $E4
13370 ;ACC IS THE CURRENT INDEX INTO TABLE
13380 ;$00 CANNOT OCCUR
13390 L0997  LSR $E4
13400        TAX 
13410        LDY MNEMHI-1,X
13420        CPY LABL40+1
13430        BCC L09AE
13440        BNE L09AA
13450        LDY MNEMLO-1,X
13460        CPY LABL40
13470        BCC L09AE
13480        BEQ L0A20 ;ENTRY FOUND IN TABLE
13490 L09AA  SBC $E4
13500        .BYTE $2C
13510 L09AE  ADC $E4
13520        LDX $E4
13530        BNE L0997
13540 ;LABEL IDENTIFIED - NOT OPCODE MNEMONIC
13550 L09B9  JSR L11DC ;EXECUTE P-CODE
13560 ;SUBTRACT CONSTANT OF 5 IN CONST5
13570 ;FROM END OF AVAILABLE MEMORY IN ENDMEM
13580 ;TO PRODUCE POINTER TO NEXT LABEL IN $0C/$0D
13590        .BYTE SUBZ,ENDMEM,CONST5,$0C
13600        .BYTE EX65
13610 L09C1  LDA $0C 
13620        CMP LABTBL
13630        LDA $0D
13640        SBC LABTBL+1
13650        BCC L0A41 ;BRANCH IF OFF END OF LABEL TABL
13660        LDA LABL40+1
13670        CMP ($0C),Y
13680        BNE L09F3 ;GO TO NEXT ENTRY IF NO MATCH
13690        LDA LABL40
13700        CMP ($0C,X)
13710        BNE L09F3 ;GO TO NEXT ENTRY IF NO MATCH
13720        LDY #$03
13730        LDA ($0C),Y
13740        CMP #$FE
13750        BCC L09E8
13760 ;LABEL NOT COMPLETELY DEFINED
13770        STA $32
13780        LDY #$05
13790        LDA ($0C),Y
13800        LDY #$03
13810 L09E8  CMP LABL40+3
13820        BNE L09F3 ;GO TO NEXT ENTRY IF NO MATCH
13830        DEY 
13840        LDA LABL40+2
13850        CMP ($0C),Y
13860        BEQ L0A02
13870 ;GO TO PREVIOUS ENTRY IN LABEL TABLE
13880 ;CONST6/$F5 CONTAINS CONSTANT OF 6
13890 L09F3  JSR L11DC ;EXECUTE P-CODE
13900        .BYTE SUBZ,$0C,CONST6,$0C
13910        .BYTE EX65
13920        STX $32 ;ASSUME LABEL DEFINED BY DEFAULT
13930        BNE L09C1 ;ALWAYS BRANCHES
13940 ;
13950 L0A02  LDA $32
13960        BNE L0A47 ;BRANCH IF LABEL UNDEFINED
13970 ;BRANCH IF LABEL IS PART OF R-VALUE
13980        LDA $30
13990        BEQ L0A44
14000 ;
14010 ;LABEL FOUND AND IT'S AN L-VALUE
14020 ;IF IT'S NOT FOLLOWED BY AN '=' SIGN,
14030 ;CHECK ITS VALUE AGAINST PRESENT LOCATION
14040        JSR L11DC ;EXECUTE P-CODE
14050        .BYTE ADDZ,$0C,CONST4,$0C ;$0C/$0D POINTS 
14060 L113C  .BYTE CLAS,L1140-*,L1140-*,L1140-*
14070 L1140  .BYTE COPY,$04,$00
14080        .BYTE CHK6+'=,L0A1F-*
14090        .BYTE BMOV,CONST2,$0C,CNST7E ;MOVE ADDR FI
14100 L0A18  .BYTE BEQU,ASMADR,LABVAL,L0A1F-*
14110 ;ERROR IF ADDRESS FIELD NOT EQUAL TO ASMADR/ASMAD
14120 ;"LABEL PREVIOUSLY DEFINED"
14130 ;ERROR 12 - LABEL PREVIOUSLY DEFINED
14140        .BYTE RERR,$0C
14150 L0A1F  .BYTE RETN
14160 ;
14170 ;CREATE NEW SYMBOL TABLE ENTRY OR
14180 ;RECORD SYMBOL TABLE OVERFLOW
14190 L0A41  LDA $7C 
14200        BNE L05F5 ;BRANCH IF TABLE ALREADY OVERFLO
14210        JSR L11DC ;EXECUTE P-CODE
14220        .BYTE BGEQ,$0C,ENDTXT,L0C22-* ;CHECK FOR 
14230 ;ERROR 25 - SYMBOL TABLE OVERFLOW
14240        .BYTE RERR,$99
14250        .BYTE SET1,$7C ;SET SYM TABLE OVERFLOW FLA
14260        .BYTE RET4 ;RETURN - 4TH BYTE OF CALL IS O
14270 L0C22  .BYTE COPY,$0C,LABTBL ;UPDATE START OF TAB
14280        .BYTE BMOV,CONST4,CNST6C,$0C ;COPY UP BASE
14290        .BYTE ADDZ,$0C,CONST4,$32
14300        .BYTE BMOV,CONST2,CNST44,$32 ;COPY UP VALU
14310        .BYTE EX65
14320        LDA $30
14330        BNE L05F5 ;RETURN IF L-VALUE ;
14340 ;LABEL IS PART OF R-VALUE SO MARK IT AS
14350 ;BEING UNDEFINED
14360        LDA LABL40+3
14370        LDY #$05
14380        STA ($0C),Y
14390        LDA #$FF
14400        LDY #$03
14410        STA ($0C),Y
14420 L05F5  JSR L11DC ;EXECUTE P-CODE
14430        .BYTE RET4 ;RETURN - 4TH BYTE OF CALL IS O
14440 ;LABEL DEFINED, AND IS PART OF R-VALUE
14450 ;MOVE ADDRESS FIELD TO LABVAL
14460 L0A44  JSR L11DC ;EXECUTE P-CODE
14470        .BYTE ADDZ,$0C,CONST4,$0C
14480        .BYTE BMOV,CONST2,$0C,CNST7E
14490        .BYTE RETN
14500 ;UNDEFINED LABEL FOUND IN LABEL TABLE
14510 L0A47  LDY #$04
14520        LDX $30
14530        BEQ L0A50 ;BRANCH IF PART OF R-VALUE
14540 ;LABEL IS BEING CONSIDERED AS L-VALUE
14550        EOR #$FE
14560 ;BRANCH IF UNDEFINED AND IT WAS PREVIOUSLY ONLY R
14570        BNE L1210
14580 ;OTHERWISE IT'S IN ZERO PAGE
14590        STA $7F
14600        LDA ($0C),Y
14610        STA LABVAL
14620        JSR L11DC ;EXECUTE P-CODE
14630        .DBYTE L0A18+OFFSET ;CHECK IT'S NOT BEEN R
14640 L1210  LDA ASMADR+1
14650        BEQ L1224 ;BRANCH TO MARK IT AS ZERO PAGE
14660        INY 
14670        STA ($0C),Y
14680        DEY 
14690        LDA ASMADR
14700        STA ($0C),Y
14710        LDA LABL40+3
14720 L121E  DEY 
14730        STA ($0C),Y
14740        JMP L0B7B
14750 L1224  LDA ASMADR
14760        STA ($0C),Y
14770        LDA #$FE
14780        BNE L121E
14790 ;UNDEFINED LABEL IS R-VALUE
14800 L0A50  EOR #$FE
14810        BNE L05F5 ;EXIT IF IT'S NEVER BEEN R-VALUE
14820        STA $7F ;PUT ITS PAGE ZERO ADDRESS INTO $7
14830        LDA ($0C),Y
14840        STA LABVAL
14850        LDA $ED ;SET FLAG TO INDICATE THAT THIS HA
14860        ORA #%01000000
14870        STA $ED
14880        JMP L02BC ;RETURN FROM P-CODE SUBROUTINE
14890 ;
14900 ;OPCODE $23 - INSTRUCTION LENGTH = 1
14910 ;DECOMPRESS TEXT POINTED TO BY TXTPOS/TXTPOS+1,
14920 ;AND STORE IT STARTING FROM $02/$03
14930 L0A60  STX $E4
14940        INY 
14950 L0A63  LDX #$FF
14960        LDA (TXTPOS),Y
14970        BPL L0A6C
14980        TAX 
14990        LDA $28
15000 L0A6C  STY $E5
15010        LDY $E4
15020 L0A70  STA ($02),Y
15030        INY 
15040        INX 
15050        BMI L0A70
15060        STA $28
15070        STY $E4
15080        LDY $E5
15090        INY 
15100        CMP #$0D
15110        BNE L0A63
15120        JMP L11CF ;GO TO NEXT INSTRUCTION
15130 ;***********************************
15140 ;MULTIPLY SUBROUTINE
15150 ;16-BIT QUANTITIES IN ZERO PAGE POINTED TO
15160 ;BY A AND Y ARE MULTIPLIED TOGETHER, AND
15170 ;THE 16-BIT RESULT IS PUT INTO THE TWO
15180 ;LOCATIONS POINTED TO BY X.  ALSO, THE
15190 ;16-BIT QUANTITY SPECIFIED BY TMPLOC+1(LO) AND
15200 ;$EC(HI) IS ADDED ON.  Z FLAG CLEARED IF RESULT
15210 ;IS GREATER THAN $FFFF.
15220 L0A84  STX $E5
15230        TAX 
15240        LDA $00,X
15250        STA $E8
15260        LDA $01,X
15270        LSR A 
15280        STA $E9
15290        LDA #$10
15300        STA TMPLOC
15310        LSR $E8
15320 L0AA0  BCC L0AB1
15330        CLC 
15340        LDA TMPLOC+1
15350        ADC $0000,Y
15360        STA TMPLOC+1
15370        LDA $EC
15380        ADC $0001,Y
15390        STA $EC
15400 L0AB1  ROR $EC
15410        ROR TMPLOC+1
15420        ROR $E9
15430        ROR $E8
15440        DEC TMPLOC
15450        BNE L0AA0
15460        LDX $E5
15470        LDA $E8
15480        STA $00,X
15490        LDA $E9
15500        STA $01,X
15510 ;CLEAR Z FLAG IF OVERFLOW
15520        LDA TMPLOC+1
15530        ORA $EC
15540        RTS 
15550 ;
15560 ;OPCODE $0A - 2ND BYTE IS BRANCH OFFSET
15570 L0AF0  .BYTE EX65
15580        TXA 
15590        LDX #$04
15600 L0AF4  STA $6B,X
15610        DEX 
15620        BNE L0AF4
15630        STA $27
15640        STA $29
15650        INY 
15660        STY $46
15670        LDA #LABL40
15680        STA $47
15690 L0B08  LDY #$00
15700        LDA ($00),Y
15710 L0B0C  CMP L0B80,X
15720        BMI L0B14
15730        CMP L0B85,X
15740        BPL L0B14
15750        LDY $27
15760        CPY #$06
15770        BCS L0B61
15780        SBC L0B8A,X
15790        STA $28
15800        LDX $47
15810        LDY $46
15820        BNE L0B48
15830        CLC 
15840        ADC $00,X
15850        STA $00,X
15860        BCC L1264
15870        INC $01,X
15880 L1264  INC $47
15890        INC $47
15900        LDA #$02
15910        STA $46
15920        BNE L0B61
15930 L0B48  LDA $00,X ;SET UP EXISTING TOTAL
15940        STA TMPLOC+1
15950        LDA $01,X
15960        STA $EC
15970        LDA L0B8F-1,Y ;SET UP MULTIPLIER (Y=1 OR 2
15980        STA $E8
15990        LDA L0B91-1,Y
16000        STA $E9
16010        LDA #$E8 ;POINTER TO MULTIPLIER
16020        LDY #$28 ;POINTER TO ENCODED CHARACTER
16030        JSR L0A84 ;MULTIPLY
16040        DEC $46
16050 L0B61  INC $00
16060        BNE L0B67
16070        INC $01
16080 L0B67  INC $27
16090        LDX #$03
16100        BNE L0B08 ;ALWAYS BRANCHES
16110 L0B6B  CMP #$07
16120        BPL L0B74
16130        JSR L11DC ;EXECUTE P-CODE
16140        .BYTE RET2 ;RETURN - 2ND BYTE OF CALL IS O
16150 L0B74  JSR L11DC
16160 ;ERROR 10 - LABEL LONGER THAN 6 CHARS
16170        .BYTE RERR,$0A
16180        .BYTE RET2 ;RETURN - 2ND BYTE OF CALL IS O
16190 L0B14  DEX 
16200        BPL L0B0C
16210        LDA $27
16220        BNE L0B6B
16230 L0B7B  JSR L11DC
16240        .BYTE RETN
16250 L0B80  .BYTE $41,$30,$2E,$24
16260 L0B85  .BYTE $5B,$3B,$2F,$25 
16270 L0B8A  .BYTE $3F,$14,$07,$FC
16280 L0B8F  .BYTE $28,$40
16290 L0B91  .BYTE $00,$06
16300 ;
16310 ;OPCODE $17 XX - PRINT CONTENTS OF LOCATION
16320 ;XX AS 2-DIGIT HEX NUMBER 
16330 L0BE5  TAX 
16340        LDA $00,X
16350        JSR HEXOUT
16360 ;ADVANCE IP AND MOVE TO NEXT INSTR
16370        JMP L11CF
16380 ;
16390 ;OPCODE $09 - INSTRUCTION LENGTH = 2
16400 ;EVALUATE EXPRESSION - RESULT IN LABVAL
16410 ;BRANCH ON SECOND BYTE IF ERROR
16420 L0C30  .BYTE SET0,$EC ;SET TO ZERO
16430        .BYTE SET0,$36
16440        .BYTE SET0,NUMVAL ;SET TO ZERO
16450 L0C39  .BYTE CHK0+SPC,L0CB4-* ;ERROR IF CR OR SP
16460        .BYTE RLBL,L0C5D-* ;BRANCH IF LABEL FOUND
16470        .BYTE ADDZ,CNST10,CONST6,$34 ;$34/$35 IS B
16480        .BYTE CHK0+'$,L0C64-* ;BRANCH IF HEX NUMB
16490        .BYTE ADDZ,CONST3,CONST5,$34 ;BASE = 8
16500        .BYTE CHK0+'@,L0C64-* ;BRANCH IF OCTAL NU
16510        .BYTE COPY,CONST2,$34 ;BASE = 2
16520        .BYTE CHK0+'%,L0C64-* ;BRANCH IF BINARY N
16530        .BYTE CHK0+$27,L0CBD-* ;BRANCH IF QUOTE
16540        .BYTE CHK0+'*,L0EFD-* ;BRANCH IF CURRENT 
16550        .BYTE COPY,CNST10,$34 ;OTHERWISE ASSUME BA
16560        .DBYTE L0C66+OFFSET
16570 ;HANDLE '*' - LOCATION COUNTER
16580 L0EFD  .BYTE COPY,ASMADR,LABVAL
16590        .DBYTE L0EDE+OFFSET
16600 ;LOOK UP VALUE OF LABEL - BRANCH IF ERROR
16610 L0C5D  .BYTE LEXP,L0CD6-*,L0CD6-*,L0CD6-*
16620        .BYTE $FB ;JMP TO L0CDC
16630 ;PROCESS NUMERIC LITERAL
16640 L0C64  .BYTE INC0 ;GO TO NEXT CHAR IF NOT DECI
16650 L0C66  .BYTE SET0,LABVAL ;SET RESULT TO ZERO
16660        .BYTE SET0,LABL40 ;LABL40 AND LABL40+1 USE
16670        .BYTE EX65
16680 L0C6D  LDY #$00
16690        LDA ($00),Y ;GET NEXT CHARACTER
16700        SEC 
16710        LDX $34
16720        SBC #$30
16730        BMI L0CA2 ;BRANCH IF NOT VALID
16740        CMP $34
16750        BPL L0C95 ;BRANCH IF OUT OF RANGE
16760 L0C78  INC LABL40 ;CHAR COUNT
16770        STA TMPLOC+1
16780        LDA #$00
16790        STA $EC
16800        LDX #LABVAL
16810        LDY #LABVAL
16820        LDA #$34
16830 ;MULTIPLY RESULT IN LABVAL BY 10 AND
16840 ;ADD ON NEW DIGIT
16850        JSR L0A84 
16860        BEQ L0C8D ;BRANCH IF NO OVERFLOW
16870        INC LABL40+1 ;OVERFLOW COUNT
16880 L0C8D  INC $00 ;INCREMENT POINTER
16890        BNE L0C6D
16900        INC $01
16910        BNE L0C6D ;THEN DO NEXT DIGIT
16920 ;DIGIT SEEMS TO BE OUT OF RANGE, BUT
16930 ;CHECK FIRST TO SEE IF IT IS VALID HEX
16940 L0C95  CPX #$10
16950        BNE L0CA2
16960 ;CARRY IS SET ANYWAY AFTER CPX 
16970        SBC #$07
16980        BMI L0CA2
16990        CMP #$10
17000        BMI L0C78
17010 ;DIGIT DEFINITELY OUT OF RANGE
17020 L0CA2  LDA LABL40 ;CHECK IF IT'S FIRST CHARACTER
17030        BEQ L0CB1 ;IF SO, "INVALID EXPRESSION"
17040        LDA LABL40+1 ;CHECK IF OVERFLOW HAS OCCURR
17050        BEQ L0CB8 ;IF NOT, VALID TERMINATION OF NU
17060        JSR L11DC ;EXECUTE P-CODE
17070 ;ERROR 3 - ADDRESS NOT VALUD
17080        .BYTE RERR,$03
17090        .BYTE $FB ;JMP TO L0CDC
17100 L0CB1  JSR L11DC ;EXECUTE P-CODE
17110 ;ERROR 7 - INVALID EXPRESSION
17120 L0CB4  .BYTE RERR,$07
17130        .BYTE RET2 ;RETURN - 2ND BYTE OF CALL IS O
17140 L0CB8  JSR L11DC ;EXECUTE P-CODE
17150        .BYTE $FB ;JMP TO L0CDC
17160 ;PROCESS SINGLE QUOTE CHARACTER
17170 L0CBD  .BYTE INC0
17180        .BYTE SET0,LABVAL ;SET LABVAL TO ZERO
17190        .BYTE MOVB,CNST7E ;AND PUT BYTE INTO LABVA
17200 L0EDE  .BYTE INC0 ;MOVE ON TO NEXT CHAR
17210        .BYTE $FB ;JMP TO L0CDC
17220 ;PROCESS UNDEFINED LABEL
17230 L0CD6  .BYTE ADDZ,CONST1,$ED,$ED
17240 ;ERROR 18 - UNDEFINED LABEL
17250        .BYTE RERR,$12
17260        .BYTE $FC ;JMP TO L0D11
17270 ;LOOK TO SEE IF THERE'S AN OPERATOR
17280 ;SET UP $06/$07 TO POINT TO PREVIOUS OPERATOR
17290 L0CDC  .BYTE COPY,$3A,$06
17300        .BYTE CHK6+'/,L0D07-* ;DIVIDE
17310        .BYTE CHK6+'*,L0CF4-* ;MULTIPLY
17320        .BYTE CHK6+'-,L0CEE-* ;SUBTRACT
17330 ;MUST BE '+' - ADD LABVAL TO NUMVAL
17340        .BYTE ADDZ,NUMVAL,LABVAL,NUMVAL
17350        .BYTE $FC ;JMP TO L0D11
17360 ;SUBTRACT - SUBTRACT LABVAL FROM NUMVAL
17370 L0CEE  .BYTE SUBZ,NUMVAL,LABVAL,NUMVAL
17380        .BYTE $FC ;JMP TO L0D11
17390 ;MULTIPLY NUMVAL BY LABVAL
17400 L0CF4  .BYTE EX65
17410        LDA #NUMVAL 
17420        LDY #LABVAL
17430        STX TMPLOC+1
17440        STX $EC
17450        TAX 
17460        JSR L0A84 ;MULTIPLY
17470        JMP L0D02
17480 ;DIVIDE NUMVAL BY LABVAL
17490 L0D07  .BYTE COPY,NUMVAL,$26
17500        .BYTE EX65
17510        LDX #$26
17520        LDY #LABVAL
17530        LDA #NUMVAL
17540        JSR L052A
17550 L0D02  JSR L11DC ;EXECUTE P-CODE
17560 ;LOOK FOR NEXT OPERATOR -
17570 ;GO TO L0D1F IF FOUND
17580 L0D11  .BYTE CHK0+'+,L0D1F-*
17590        .BYTE CHK0+'-,L0D1F-*
17600        .BYTE CHK0+'*,L0D1F-*
17610        .BYTE CHK0+'/,L0D1F-*
17620 ;OTHERWISE, EXIT
17630 ;SET TOP BIT OF $ED TO 1
17640 ;IF RESULT $0100 OR GREATER.
17650        .BYTE BLES,NUMVAL,CONST1-1,L0D30-*
17660        .BYTE ADDZ,CNST80,$ED,$ED
17670 L0D30  .BYTE RETN
17680 ;OPERATOR FOUND - SO MOVE IT INTO
17690 ;LOCATION POINTED TO BY $3A/$3B
17700 L0D1F  .BYTE MOVB,$3A
17710        .BYTE INC0
17720        .DBYTE L0C39+OFFSET ;MOVE ON TO NEXT CHARA
17730 L0D34  JSR L11DC ;EXECUTE P-CODE
17740 ;ERROR 5 - ILLEGAL OPERAND TYPE FOR THIS INSTR
17750        .BYTE RERR,$05
17760        .BYTE $FF ;JMP TO LINOUT
17770 L0D3D  .BYTE EX65
17780        LDY #$FF 
17790        LDA DRTYPE+1
17800        AND $57
17810        BNE L0D4F
17820        LDY #$07
17830        LDA DRTYPE
17840        AND $56
17850        BEQ L0D34
17860 L0D4F  ROL A 
17870        INY 
17880        BCC L0D4F
17890        CPY #$08
17900        BPL L0DB1
17910        LDA L0DFD,Y
17920        AND #$2A
17930        BNE L0D90
17940        TYA 
17950        BNE L0DB1
17960        LDA #$3F
17970        BIT $ED
17980        BNE L0DB1
17990        JSR L11DC ;EXECUTE P-CODE
18000        .BYTE SUBZ,NUMVAL,ASMADR,NUMVAL
18010        .BYTE SUBZ,NUMVAL,CONST2,NUMVAL
18020        .BYTE BLES,NUMVAL,CNST80,L0D8C-*
18030        .BYTE ADDZ,NUMVAL,CNST80,$1C
18040        .BYTE BLES,$1C,CNST80,L0D8C-*
18050 ;ERROR 16 - RELATIVE BRANCH OUT OF RANGE
18060        .BYTE RERR,$10
18070        .BYTE DECR,INSTLN
18080        .BYTE $FF ;JMP TO LINOUT
18090 L0D90  LDA $ED
18100        ASL A 
18110        BNE L0DA6
18120        BCC L0DB1
18130        INY 
18140        LDA L0DFD,Y
18150        AND DRTYPE+1
18160        BNE L0DB1
18170        JSR L11DC ;EXECUTE P-CODE
18180 ;ERROR 3 - ADDRESS NOT VALID
18190        .BYTE RERR,$03
18200        .BYTE $FF ;JMP TO LINOUT
18210 L0DA6  INY 
18220        LDA L0DFD,Y
18230        STY DRTYPE
18240        AND DRTYPE+1
18250        BNE L0DCE
18260        .BYTE $24
18270 L0D8C  .BYTE EX65
18280        DEY 
18290 L0DB1  LDA $20
18300        LSR A 
18310        LDA L0E0D,Y
18320        BCS L0DBC
18330        LDA L0E19,Y
18340 L0DBC  CLC 
18350        ADC $20
18360        STA INSTRN
18370        LDA L0DF1,Y
18380        STA INSTLN
18390        JSR L11DC ;EXECUTE P-CODE
18400        .BYTE COPY,NUMVAL,INSTRN+1
18410        .BYTE $FF ;JMP TO LINOUT
18420 L0DCE  JSR L11DC ;EXECUTE P-CODE
18430 ;ERROR 19 - FWD REF TO PAGE ZERO MEMORY
18440        .BYTE RERR,$13
18450        .BYTE EX65
18460        LDY DRTYPE 
18470        JMP L0DB1
18480 L0DD5  .BYTE $60,$60,$00,$80,$00,$00,$00
18490        .BYTE $00,$00,$00,$10,$00,$00,$00
18500 L0DE3  .BYTE $7D,$3D,$3C,$3C,$73,$32,$7C
18510        .BYTE $38,$70,$30,$10,$10,$00,$80
18520 L0DF1  .BYTE $02,$02,$02,$03,$02
18530        .BYTE $03,$02,$03,$01,$02,$02,$03
18540 L0DFD  .BYTE $80,$40,$20,$10
18550        .BYTE $08,$04,$02,$01
18560 L0E0D  .BYTE $00,$08,$04,$0C,$14,$1C
18570        .BYTE $00,$18,$00,$10,$00,$00
18580 L0E19  .BYTE $00,$00,$04,$0C,$14,$1C
18590        .BYTE $14,$1C,$08,$00,$00,$2C
18600 ;
18610 ;OUTPUT ACCUMLATOR AS HEX NUMBER, BUT
18620 ;ADD ONTO CHKSUM FIRST
18630 HEXCHK PHA 
18640        CLC 
18650        ADC CHKSUM
18660        STA CHKSUM
18670        BCC L1942
18680        INC CHKSUM+1
18690 L1942  PLA 
18700 ;OUTPUT ACCUMLATOR AS HEX NUMBER
18710 HEXOUT PHA 
18720        LSR A 
18730        LSR A 
18740        LSR A 
18750        LSR A 
18760        JSR HEXDIG ;PRINT SINGLE HEX DIGIT IN ACCU
18770        PLA 
18780        AND #$0F
18790 ;PRINT SINGLE HEX DIGIT IN ACCUMULATOR
18800 HEXDIG ORA #'0
18810        CMP #'9+1
18820        BCC L132E
18830        ADC #6
18840 L132E  JMP COUT
18850 ;A2 - ASSEMBLE TO HEX FILE
18860 A2OUT  .BYTE EX65
18870        DEY ;Y = 0
18880        LSR ASMBRK
18890        LDA INSTLN
18900        STA $E4
18910        BCS FLUSHB
18920 L10DA  DEC $E4
18930        BMI ADDLNP
18940        LDX A2BLEN
18950        LDA INSTRN,Y
18960        STA A2BUFF,X
18970        INY 
18980        INX 
18990        STX A2BLEN
19000        CPX #24 ;BUFFER IS MAX 24 CHARS
19010        BNE L10DA
19020 ;FLUSH THE BUFFER FOR A2 OPTION
19030 FLUSHB LDX A2BLEN
19040        BEQ L126A
19050        LDA #';
19060        JSR COUT ;PRINT CHARACTER IN ACC
19070 ;PRINT NUMBER OF BYTES AND START ADDR
19080        TXA 
19090        JSR HEXCHK
19100        LDX #2
19110 L10FF  LDA BUFADR-1,X
19120        JSR HEXCHK
19130        DEX 
19140        BNE L10FF
19150 ;PRINT DATA BYTES
19160 L1107  LDA A2BUFF,X
19170        JSR HEXCHK
19180        INX 
19190        DEC A2BLEN
19200        BNE L1107
19210 ;PRINT CHECKSUM
19220        LDA CHKSUM+1
19230        JSR HEXOUT
19240        LDA CHKSUM
19250        JSR HEXOUT
19260        JSR NEWLIN
19270 ;PRINT SIX NULL CHARACTERS
19280        LDX #$06
19290 L1262  LDA #$00
19300        JSR COUT ;PRINT CHARACTER IN ACC
19310        DEX 
19320        BNE L1262
19330 L126A  STX CHKSUM
19340        STX CHKSUM+1
19350 ;SET START ADDRESS OF NEXT BLOCK
19360        CLC 
19370        TYA 
19380        ADC ASMADR
19390        STA BUFADR
19400        LDA #$00
19410        ADC ASMADR+1
19420        STA BUFADR+1
19430        JMP L10DA
19440 ;
19450 ADDLNP JSR L11DC ;EXECUTE P-CODE
19460 ;ADD INSTRUCTION LENGTH ONTO CURRENT
19470 ;LOCATION THEN EXIT
19480 ADDLEN .BYTE ADDZ,ASMADR,INSTLN,ASMADR
19490        .BYTE RETN
19500 ;
19510 ;A2 OR A3 OPTIONS
19520 A2ORA3 .BYTE BEQU,ASMOPT,CONST2,A2OUT-*
19530 ;
19540 ;A3 - ASSEMBLE TO MEMORY
19550        .BYTE ADDZ,ASMADR,ASMOFS,$1C ;ADD OFFSET
19560        .BYTE BMOV,INSTLN,CNST50,$1C ;COPY INSTR T
19570        .DBYTE L0E34+OFFSET ;CHECK FOR ASM ERRORS
19580 ;
19590 ;OPCODE $08 - INSTRUCTION LENGTH = 1
19600 ;OUTPUT CURRENT ASSEMBLER INSTRUCTION
19610 ;RELEVANT LOCATIONS:
19620 ;NUMERR = ZERO IF NO ERRORS ON THIS LINE
19630 ;
19640 ;GO TO A2ORA3 IF A2/A3 OPTION, AND PASS 2
19650 L10B3  .BYTE BNEQ,PASS,CONST2,L10BD-*
19660        .BYTE BGEQ,ASMOPT,CONST2,A2ORA3-*
19670 ;
19680 ;GO TO ADDLEN IF ERROR, OR IF IT'S BOTH PASS 2 AN
19690 ;A LISTING IS REQUIRED.
19700 L10BD  .BYTE BEQU,PASS,CONST1,L0E34-* ;BR IF PAS
19710        .BYTE BEQU,ASMOPT,CONST0,L0E39-* ;BR IF L
19720 ;GO TO ADDLEN IF NO ERRORS
19730 L0E34  .BYTE BEQU,CONST0,NUMERR,ADDLEN-*
19740 ;
19750 ;OUTPUT LINE OF ASSEMBLY LISTING
19760 L0E39  .BYTE PDEC,LINENO ;PRINT LINE NO
19770        .BYTE BEQU,PASS,CONST1,L0E6A-* ;BRANCH IF
19780        .BYTE MESG,' ',$00 ;PRINT SPACE
19790        .BYTE PHEX,ASMADR+1 ;PRINT CURRENT ADDRESS
19800        .BYTE PHEX,ASMADR
19810        .BYTE MESG,' ',$00 ;PRINT SPACE
19820 ;
19830 ;PRINT 0, 1, 2 OR 3 BYTES OF OBJECT CODE,
19840 ;PLUS SPACES TO PAD IT OUT
19850        .BYTE BNEQ,INSTLN,CONST0,PRINST-*
19860        .BYTE MESG,'  ',$00
19870 TWOSPC .BYTE MESG,'  ',$00
19880 ONESPC .BYTE MESG,'  ',$00
19890 ;
19900 ;IF PRFLAG IS SET THEN THE LINE HAS ALREADY
19910 ;BEEN PRINTED - APPLIES FOR DIRECTIVES, WHICH
19920 ;MAY PRODUCE MORE THAN ONE LINE OF OUTPUT.
19930 L0E6A  .BYTE BEQU,CONST1,PRFLAG,L0EC5-*
19940        .BYTE MESG,' ',$00
19950        .BYTE PLIN,$02 ;PRINT OUT LINE OF TEXT 
19960        .BYTE SET1,PRFLAG ;SET PRFLAG
19970 ;
19980 ;PROCESS ASSEMBLY ERRORS
19990 L0E77  .BYTE GERR,$20,ADDLEN-* ;BR IF NO ERRORS
20000        .BYTE ADDZ,$06,CONST6,$06 ;ADD 6 TO $06/$0
20010        .BYTE BEQU,PASS,CONST1,L0E9E-* ;BRANCH IF
20020        .BYTE ADDZ,$06,CNST12,$06 ;ADD 12 TO $06/$
20030 L0E9E  .BYTE PERR,'E#',$00
20040        .BYTE PDEC,$20 ;PRINT ERROR NUMBER
20050 L0EC5  .BYTE MESG,$0D ;END OF LINE
20060        .DBYTE L0E77+OFFSET ;LOOK FOR NEXT ERROR
20070 ;
20080 PRINST .BYTE PHEX,INSTRN
20090        .BYTE BEQU,INSTLN,CONST1,TWOSPC-*
20100        .BYTE PHEX,INSTRN+1
20110        .BYTE BEQU,INSTLN,CONST2,ONESPC-*
20120        .BYTE PHEX,INSTRN+2
20130        .DBYTE L0E6A+OFFSET
20140 ;
20150 ;TABLE OF OPCODE MNEMONICS
20160 ;LOW BYTE OF MNEMONIC IN BASE-40
20170 MNEMLO .BYTE $40 ;A
20180        .BYTE $E3 ;ADC
20190        .BYTE $74 ;AND
20200        .BYTE $44 ;ASL
20210        .BYTE $FB ;BCC
20220        .BYTE $0B ;BCS
20230        .BYTE $59 ;BEQ
20240        .BYTE $FC ;BIT
20250        .BYTE $91 ;BMI
20260        .BYTE $B5 ;BNE
20270        .BYTE $0C ;BPL
20280        .BYTE $5B ;BRK
20290        .BYTE $F3 ;BVC
20300        .BYTE $03 ;BVS
20310        .BYTE $A3 ;CLC
20320        .BYTE $A4 ;CLD
20330        .BYTE $A9 ;CLI
20340        .BYTE $B6 ;CLV
20350        .BYTE $D8 ;CMP
20360        .BYTE $58 ;CPX
20370        .BYTE $59 ;CPY
20380        .BYTE $CB ;DEC
20390        .BYTE $E0 ;DEX
20400        .BYTE $E1 ;DEY
20410        .BYTE $AA ;EOR
20420        .BYTE $73 ;INC
20430        .BYTE $88 ;INX
20440        .BYTE $89 ;INY
20450        .BYTE $98 ;JMP
20460        .BYTE $8A ;JSR
20470        .BYTE $A1 ;LDA
20480        .BYTE $B8 ;LDX
20490        .BYTE $B9 ;LDY
20500        .BYTE $0A ;LSR
20510        .BYTE $E8 ;NOP
20520        .BYTE $91 ;ORA
20530        .BYTE $41 ;PHA
20540        .BYTE $50 ;PHP
20550        .BYTE $E1 ;PLA
20560        .BYTE $F0 ;PLP
20570        .BYTE $E4 ;ROL
20580        .BYTE $EA ;ROR
20590        .BYTE $A9 ;RTI
20600        .BYTE $B3 ;RTS
20610        .BYTE $13 ;SBC
20620        .BYTE $8B ;SEC
20630        .BYTE $8C ;SED
20640        .BYTE $91 ;SEI
20650        .BYTE $E1 ;STA
20660        .BYTE $F8 ;STX
20670        .BYTE $F9 ;STY
20680        .BYTE $40 ;TAX
20690        .BYTE $41 ;TAY
20700        .BYTE $10 ;TSX
20710        .BYTE $C1 ;TXA
20720        .BYTE $D3 ;TXS
20730        .BYTE $E9 ;TYA
20740 ;THESE LAST SIX BYTES ARE NOT NEEDED
20750 ;BECAUSE NO BASE-40 ENCODING CAN
20760 ;EXCEED $FF00.
20770 ;.BYTE $FF ;NULL
20780 ;.BYTE $FF ;NULL
20790 ;.BYTE $FF ;NULL
20800 ;.BYTE $FF ;NULL
20810 ;.BYTE $FF ;NULL
20820 ;.BYTE $FF ;NULL
20830 ;
20840 ;TABLE OF OPCODE MNEMONICS
20850 ;HIGH BYTE OF MNEMONIC IN BASE-40
20860 MNEMHI .BYTE $06 ;A
20870        .BYTE $06 ;ADC
20880        .BYTE $08 ;AND
20890        .BYTE $09 ;ASL
20900        .BYTE $0C ;BCC
20910        .BYTE $0D ;BCS
20920        .BYTE $0D ;BEQ
20930        .BYTE $0D ;BIT
20940        .BYTE $0E ;BMI
20950        .BYTE $0E ;BNE
20960        .BYTE $0F ;BPL
20970        .BYTE $0F ;BRK
20980        .BYTE $0F ;BVC
20990        .BYTE $10 ;BVS
21000        .BYTE $14 ;CLC
21010        .BYTE $14 ;CLD
21020        .BYTE $14 ;CLI
21030        .BYTE $14 ;CLV
21040        .BYTE $14 ;CMP
21050        .BYTE $15 ;CPX
21060        .BYTE $15 ;CPY
21070        .BYTE $19 ;DEC
21080        .BYTE $19 ;DEX
21090        .BYTE $19 ;DEY
21100        .BYTE $21 ;EOR
21110        .BYTE $3A ;INC
21120        .BYTE $3A ;INX
21130        .BYTE $3A ;INY
21140        .BYTE $40 ;JMP
21150        .BYTE $41 ;JSR
21160        .BYTE $4B ;LDA
21170        .BYTE $4B ;LDX
21180        .BYTE $4B ;LDY
21190        .BYTE $4E ;LSR
21200        .BYTE $59 ;NOP
21210        .BYTE $60 ;ORA
21220        .BYTE $65 ;PHA
21230        .BYTE $65 ;PHP
21240        .BYTE $65 ;PLA
21250        .BYTE $65 ;PLP
21260        .BYTE $72 ;ROL
21270        .BYTE $72 ;ROR
21280        .BYTE $73 ;RTI
21290        .BYTE $73 ;RTS
21300        .BYTE $77 ;SBC
21310        .BYTE $77 ;SEC
21320        .BYTE $77 ;SED
21330        .BYTE $77 ;SEI
21340        .BYTE $79 ;STA
21350        .BYTE $79 ;STX
21360        .BYTE $79 ;STY
21370        .BYTE $7D ;TAX
21380        .BYTE $7D ;TAY
21390        .BYTE $80 ;TSX
21400        .BYTE $80 ;TXA
21410        .BYTE $80 ;TXS
21420        .BYTE $80 ;TYA
21430        .BYTE $FF ;NULL
21440        .BYTE $FF ;NULL
21450        .BYTE $FF ;NULL
21460 ;LAST THREE ENTRIES CAN BE REMOVED
21470 ;BECAUSE THEY WILL NEVER BE REACHED BY
21480 ;THE BINARY SEARCH ALGORITHM
21490 ;.BYTE $FF ;NULL
21500 ;.BYTE $FF ;NULL
21510 ;.BYTE $FF ;NULL
21520 ;
21530 ;TABLE OF OPCODE MNEMONICS
21540 ;INSTRUCTION BASE:
21550 INSBAS .BYTE $61 ;ADC
21560        .BYTE $21 ;AND
21570        .BYTE $02 ;ASL
21580        .BYTE $90 ;BCC
21590        .BYTE $B0 ;BCS
21600        .BYTE $F0 ;BEQ
21610        .BYTE $20 ;BIT
21620        .BYTE $30 ;BMI
21630        .BYTE $D0 ;BNE
21640        .BYTE $10 ;BPL
21650        .BYTE $00 ;BRK
21660        .BYTE $50 ;BVC
21670        .BYTE $70 ;BVS
21680        .BYTE $18 ;CLC
21690        .BYTE $D8 ;CLD
21700        .BYTE $58 ;CLI
21710        .BYTE $B8 ;CLV
21720        .BYTE $C1 ;CMP
21730        .BYTE $E0 ;CPX
21740        .BYTE $C0 ;CPY
21750        .BYTE $C2 ;DEC
21760        .BYTE $CA ;DEX
21770        .BYTE $88 ;DEY
21780        .BYTE $41 ;EOR
21790        .BYTE $E2 ;INC
21800        .BYTE $E8 ;INX
21810        .BYTE $C8 ;INY
21820        .BYTE $40 ;JMP
21830        .BYTE $14 ;JSR
21840        .BYTE $A1 ;LDA
21850        .BYTE $A2 ;LDX
21860        .BYTE $A0 ;LDY
21870        .BYTE $42 ;LSR
21880        .BYTE $EA ;NOP
21890        .BYTE $01 ;ORA
21900        .BYTE $48 ;PHA
21910        .BYTE $08 ;PHP
21920        .BYTE $68 ;PLA
21930        .BYTE $28 ;PLP
21940        .BYTE $22 ;ROL
21950        .BYTE $62 ;ROR
21960        .BYTE $40 ;RTI
21970        .BYTE $60 ;RTS
21980        .BYTE $E1 ;SBC
21990        .BYTE $38 ;SEC
22000        .BYTE $F8 ;SED
22010        .BYTE $78 ;SEI
22020        .BYTE $81 ;STA
22030        .BYTE $82 ;STX
22040        .BYTE $80 ;STY
22050        .BYTE $AA ;TAX
22060        .BYTE $A8 ;TAY
22070        .BYTE $BA ;TSX
22080        .BYTE $8A ;TXA
22090        .BYTE $9A ;TXS
22100        .BYTE $98 ;TYA
22110 ;
22120 ;TABLE OF OPCODE MNEMONICS
22130 ;INSTRUCTION TYPE:
22140 INSTYP .BYTE $0F ;A
22150        .BYTE $00 ;ADC, AND
22160        .BYTE $3D ;ASL, BCC
22170        .BYTE $DD ;BCS, BEQ
22180        .BYTE $9D ;BIT, BMI
22190        .BYTE $DD ;BNE, BPL
22200        .BYTE $CD ;BRK, BVC
22210        .BYTE $DC ;BVS, CLC
22220        .BYTE $CC ;CLD, CLI
22230        .BYTE $C0 ;CLV, CMP
22240        .BYTE $88 ;CPX, CPY
22250        .BYTE $2C ;DEC, DEX
22260        .BYTE $C0 ;DEY, EOR
22270        .BYTE $2C ;INC, INX
22280        .BYTE $CA ;INY, JMP
22290        .BYTE $B0 ;JSR, LDA
22300        .BYTE $46 ;LDX, LDY
22310        .BYTE $3C ;LSR, NOP
22320        .BYTE $0C ;ORA, PHA
22330        .BYTE $CC ;PHP, PLA
22340        .BYTE $C3 ;PLP, ROL
22350        .BYTE $3C ;ROR, RTI
22360        .BYTE $C0 ;RTS, SBC
22370        .BYTE $CC ;SEC, SED
22380        .BYTE $C1 ;SEI, STA
22390        .BYTE $57 ;STX, STY
22400        .BYTE $CC ;TAX, TAY
22410        .BYTE $CC ;TSX, TXA
22420        .BYTE $CC ;TXS, TYA
22430 ;
22440 L1028  .BYTE SET0,INSTLN
22450        .BYTE INC0
22460        .BYTE SKIP ;SKIP SPACES
22470        .BYTE EXPR,LINOUT-*
22480        .BYTE CHK0+SPC,L1036-*
22490        .BYTE $FE ;JMP TO L08E6
22500 L1036  .BYTE COPY,$02,$00
22510        .BYTE SKIP ;SKIP SPACES
22520        .BYTE RLBL,L103D-*
22530 L103D  .BYTE LVAL,L104C-*,L104C-*,L104C-*
22540        .BYTE COPY,NUMVAL,LABVAL
22550        .BYTE BMOV,CONST2,CNST7E,$0C
22560        .BYTE GERR,DRTYPE,L104C-*
22570 L104C  .BYTE $FF ;JMP TO LINOUT
22580 L104E  .BYTE EX65
22590        STX DRTYPE+1
22600        LDX #$03 
22610 L1051  LDA LABL40+1
22620        CMP DIRHI,X
22630        BEQ L1062
22640 L105D  DEX 
22650        BPL L1051
22660        JSR L11DC ;EXECUTE P-CODE
22670        .DBYTE L114F+OFFSET
22680 DIRHI  .BYTE ADDZ,TXTPOS,$92,$19
22690 L10A7  .BYTE SET0,INSTLN
22700 ;OUTPUT LINE OF ASSEMBLED CODE THEN
22710 ;MOVE ON TO NEXT LINE
22720 LINOUT .BYTE OUTP ;OUTPUT ASSEMBLED LINE
22730 ;GET NEXT LINE AND GO TO L10B0 IF END
22740 L10AB  .BYTE NXLN,L10B0-*
22750        .DBYTE L085D+OFFSET ;PROCESS NEXT LINE
22760 L1062  STX DRTYPE
22770        CPX #3
22780        BNE STDRLN
22790        DEX 
22800 STDRLN STX INSTLN
22810        JSR L11DC ;EXECUTE P-CODE
22820        .BYTE SKIP ;SKIP SPACES
22830 ;IF .BYT, .WOR, OR .DBY, GO TO L1230
22840        .BYTE BNEQ,DRTYPE,CONST0,L1230-*
22850        .BYTE OUTP
22860 ;END OF SOURCE FILE REACHED
22870 L10B0  .BYTE BNEQ,ASMOPT,CONST2,L0E8A-*
22880 ;IF DOING 'A2', FLUSH BUFFER
22890        .BYTE SET1,ASMBRK
22900        .BYTE OUTP
22910 L0E8A  .BYTE INCR,PASS ;NEXT PASS
22920 ;GO BACK TO NXTPAS TO START NEXT PASS
22930        .BYTE BRGR,PASS,CONST2,L0E94-*
22940        .DBYTE NXTPAS+OFFSET
22950 L0E94  .BYTE $FD ;JMP TO L0620
22960 L123B  .BYTE BEQU,DRTYPE,CONST1,L1244-*
22970 L1241  .BYTE $FE ;JMP TO L08E6
22980 L1246  .BYTE CHK0+$0D,L1098-*
22990        .BYTE MOVB,$72
23000        .BYTE OUTP
23010 L1244  .BYTE INC0
23020        .BYTE CHK0+$27,L1251-* ;SINGLE QUOTE CHAR
23030        .DBYTE L1246+OFFSET
23040 L1251  .BYTE INC0
23050        .BYTE CHK0+$27,L1246-* ;SINGLE QUOTE CHAR
23060 L1098  .DBYTE L108E+OFFSET
23070 L109A  .BYTE INC0
23080 ;PROCESS .BYTE, .WORD OR .DBYTE
23090 L1230  .BYTE CHK0+$27,L123B-* ;SINGLE QUOTE
23100        .BYTE EXPR,L1241-*
23110        .BYTE COPY,NUMVAL,INSTRN
23120        .BYTE BNEQ,DRTYPE,CONST3,L108A-*
23130        .BYTE EX65
23140        LDA INSTRN
23150        LDY INSTRN+1
23160        STA INSTRN+1
23170        STY INSTRN
23180        JSR L11DC ;EXECUTE P-CODE
23190 L108A  .BYTE OUTP
23200 L108E  .BYTE CHK0+',,L109A-*
23210        .BYTE CHK0+SPC,L10AB-*
23220 ;ERROR 7 - INVALID EXPRESSION
23230        .BYTE RERR,$07
23240        .BYTE $FF ;JMP TO LINOUT
23250 ;
23260 ;ZERO PAGE LOCATIONS TO BE UPDATED UPON STARTUP
23270 ZPADDR .BYTE $02,IP,IP+1,$2E
23280        .BYTE $2F,CNST14,$3A,CNST10
23290        .BYTE CONST1,CONST3,NOPBYT,NOPBYT+1
23300        .BYTE CNST80,$5B,$5D,$5E
23310        .BYTE $60,$62,$65,$67
23320        .BYTE CNST50,CONST2,CNST12,CNST7E
23330        .BYTE CNST6C,CNST44,CONST4,$EE
23340        .BYTE CONST5,CONST6,$00,$80
23350        .BYTE ASMOFS,ASMOFS+1,STTEXT,STTEXT+1
23360        .BYTE ENDMEM,ENDMEM+1,ENDTXT,ENDTXT+1
23370 ;
23380 ;VALUES TO BE PUT IN THESE MEMORY LOCATIONS
23390 ZPCONT .BYTE $80
23400        .WORD PINIT
23410        .BYTE $FF
23420        .BYTE $FF,LINENO,$36,10
23430        .BYTE 1,3,$EA,$EA ;$EA IS A NOP INSTRUCTIO
23440        .BYTE $80,$B0,$40,$20
23450        .BYTE $40,$10,$0C,$03
23460        .BYTE INSTRN,2,12,LABVAL
23470        .BYTE LABL40,ASMADR,4,$37
23480        .BYTE 5,6,$80,$0D
23490 ;LAST 8 BYTES OF ASSEMBLER CODE:
23500 ;2 BYTES OFFSET FOR A3 ASSEMBLE TO MEMORY
23510 ;2 BYTES START OF AVAILABLE MEMORY
23520 ;2 BYTES END OF AVAILABLE MEMORY
23530 ;2 BYTES END OF ASSEMBLER SOURCE TEXT
23540        .WORD 0,LOMEM,HIMEM
23550 ENDIMG .WORD LOMEM