230 lines
5.5 KiB
ArmAsm
230 lines
5.5 KiB
ArmAsm
.segment "CODE"
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; ----------------------------------------------------------------------------
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; "FOR" STATEMENT
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;
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; FOR PUSHES 18 BYTES ON THE STACK:
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; 2 -- TXTPTR
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; 2 -- LINE NUMBER
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; 5 -- INITIAL (CURRENT) FOR VARIABLE VALUE
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; 1 -- STEP SIGN
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; 5 -- STEP VALUE
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; 2 -- ADDRESS OF FOR VARIABLE IN VARTAB
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; 1 -- FOR TOKEN ($81)
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; ----------------------------------------------------------------------------
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FOR:
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lda #$80
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sta SUBFLG
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jsr LET
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jsr GTFORPNT
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bne L2619
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txa
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adc #FOR_STACK1
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tax
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txs
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L2619:
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pla
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pla
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lda #FOR_STACK2
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jsr CHKMEM
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jsr DATAN
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clc
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tya
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adc TXTPTR
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pha
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lda TXTPTR+1
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adc #$00
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pha
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lda CURLIN+1
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pha
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lda CURLIN
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pha
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lda #TOKEN_TO
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jsr SYNCHR
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jsr CHKNUM
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jsr FRMNUM
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lda FACSIGN
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ora #$7F
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and FAC+1
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sta FAC+1
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lda #<STEP
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ldy #>STEP
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sta INDEX
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sty INDEX+1
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jmp FRM_STACK3
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; ----------------------------------------------------------------------------
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; "STEP" PHRASE OF "FOR" STATEMENT
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; ----------------------------------------------------------------------------
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STEP:
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lda #<CON_ONE
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ldy #>CON_ONE
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jsr LOAD_FAC_FROM_YA
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jsr CHRGOT
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cmp #TOKEN_STEP
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bne L2665
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jsr CHRGET
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jsr FRMNUM
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L2665:
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jsr SIGN
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jsr FRM_STACK2
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lda FORPNT+1
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pha
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lda FORPNT
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pha
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lda #$81
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pha
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; ----------------------------------------------------------------------------
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; PERFORM NEXT STATEMENT
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; ----------------------------------------------------------------------------
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NEWSTT:
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jsr ISCNTC
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lda TXTPTR
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ldy TXTPTR+1
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cpy #>INPUTBUFFER
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beq LC6D4
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sta OLDTEXT
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sty OLDTEXT+1
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LC6D4:
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ldy #$00
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L2683:
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lda (TXTPTR),y
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bne COLON; new: 1 cycle more on ":" case
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ldy #$02
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lda (TXTPTR),y
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clc
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jeq L2701
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iny
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lda (TXTPTR),y
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sta CURLIN
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iny
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lda (TXTPTR),y
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sta CURLIN+1
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tya
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adc TXTPTR
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sta TXTPTR
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bcc NEWSTT2
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inc TXTPTR+1
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NEWSTT2:
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jsr CHRGET
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jsr EXECUTE_STATEMENT
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jmp NEWSTT
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; ----------------------------------------------------------------------------
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; EXECUTE A STATEMENT
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;
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; (A) IS FIRST CHAR OF STATEMENT
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; CARRY IS SET
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; ----------------------------------------------------------------------------
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EXECUTE_STATEMENT:
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beq RET2
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EXECUTE_STATEMENT1:
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sbc #$80
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bcc LET1; new: 1 cycle more on assignment
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cmp #NUM_TOKENS
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bcs LC721
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asl a
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tay
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lda TOKEN_ADDRESS_TABLE+1,y
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pha
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lda TOKEN_ADDRESS_TABLE,y
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pha
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jmp CHRGET
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LET1:
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jmp LET
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COLON:
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cmp #$3A
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beq NEWSTT2
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SYNERR1:
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jmp SYNERR
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LC721:
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cmp #TOKEN_GO-$80
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bne SYNERR1
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jsr CHRGET
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lda #TOKEN_TO
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jsr SYNCHR
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jmp GOTO
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; ----------------------------------------------------------------------------
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; "RESTORE" STATEMENT
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; ----------------------------------------------------------------------------
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RESTORE:
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sec
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lda TXTTAB
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sbc #$01
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ldy TXTTAB+1
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bcs SETDA
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dey
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SETDA:
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sta DATPTR
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sty DATPTR+1
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RET2:
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rts
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.include "iscntc.s"
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;!!! runs into "STOP"
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; ----------------------------------------------------------------------------
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; "STOP" STATEMENT
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; ----------------------------------------------------------------------------
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STOP:
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bcs END2
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; ----------------------------------------------------------------------------
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; "END" STATEMENT
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; ----------------------------------------------------------------------------
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END:
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clc
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END2:
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bne RET1
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lda TXTPTR
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ldy TXTPTR+1
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; BUG on AppleSoft I
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; fix exists on AppleSoft II
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; TXTPTR+1 will always be > 0
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ldx CURLIN+1
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inx
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beq END4
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sta OLDTEXT
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sty OLDTEXT+1
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CONTROL_C_TYPED:
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lda CURLIN
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ldy CURLIN+1
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sta OLDLIN
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sty OLDLIN+1
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END4:
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pla
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pla
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L2701:
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lda #<QT_BREAK
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ldy #>QT_BREAK
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ldx #$00
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stx Z14
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bcc L270E
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jmp PRINT_ERROR_LINNUM
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L270E:
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jmp RESTART
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; ----------------------------------------------------------------------------
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; "CONT" COMMAND
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; ----------------------------------------------------------------------------
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CONT:
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bne RET1
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ldx #ERR_CANTCONT
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ldy OLDTEXT+1
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bne L271C
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jmp ERROR
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L271C:
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lda OLDTEXT
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sta TXTPTR
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sty TXTPTR+1
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lda OLDLIN
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ldy OLDLIN+1
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sta CURLIN
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sty CURLIN+1
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RET1:
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rts
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