Routines
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A742: perform FOR
A742 A9 80 LDA #$80 set FNX
A744 85 10 STA $10 set subscript/FNX flag
A746 20 A5 A9 JSR $A9A5 perform LET
A749 20 8A A3 JSR $A38A search the stack for FOR or GOSUB activity
A74C D0 05 BNE $A753 branch if FOR, this variable, not found
FOR, this variable, was found so first we dump the old one
A74E 8A TXA copy index
A74F 69 0F ADC #$0F add FOR structure size-2
A751 AA TAX copy to index
A752 9A TXS set stack (dump FOR structure (-2 bytes))
A753 68 PLA pull return address
A754 68 PLA pull return address
A755 A9 09 LDA #$09 we need 18d bytes !
A757 20 FB A3 JSR $A3FB check room on stack for 2*A bytes
A75A 20 06 A9 JSR $A906 scan for next BASIC statement ([:] or [EOL])
A75D 18 CLC clear carry for add
A75E 98 TYA copy index to A
A75F 65 7A ADC $7A add BASIC execute pointer low byte
A761 48 PHA push onto stack
A762 A5 7B LDA $7B get BASIC execute pointer high byte
A764 69 00 ADC #$00 add carry
A766 48 PHA push onto stack
A767 A5 3A LDA $3A get current line number high byte
A769 48 PHA push onto stack
A76A A5 39 LDA $39 get current line number low byte
A76C 48 PHA push onto stack
A76D A9 A4 LDA #$A4 set "TO" token
A76F 20 FF AE JSR $AEFF scan for CHR$(A), else do syntax error then warm start
A772 20 8D AD JSR $AD8D check if source is numeric, else do type mismatch
A775 20 8A AD JSR $AD8A evaluate expression and check is numeric, else do type mismatch
A778 A5 66 LDA $66 get FAC1 sign (b7)
A77A 09 7F ORA #$7F set all non sign bits
A77C 25 62 AND $62 and FAC1 mantissa 1
A77E 85 62 STA $62 save FAC1 mantissa 1
A780 A9 8B LDA #$8B set return address low byte
A782 A0 A7 LDY #$A7 set return address high byte
A784 85 22 STA $22 save return address low byte
A786 84 23 STY $23 save return address high byte
A788 4C 43 AE JMP $AE43 round FAC1 and put on stack, returns to next instruction
A78B A9 BC LDA #$BC set 1 pointer low address, default step size
A78D A0 B9 LDY #$B9 set 1 pointer high address
A78F 20 A2 BB JSR $BBA2 unpack memory (AY) into FAC1
A792 20 79 00 JSR $0079 scan memory
A795 C9 A9 CMP #$A9 compare with STEP token
A797 D0 06 BNE $A79F if not "STEP" continue
was step so ....
A799 20 73 00 JSR $0073 increment and scan memory
A79C 20 8A AD JSR $AD8A evaluate expression and check is numeric, else do type mismatch
A79F 20 2B BC JSR $BC2B get FAC1 sign, return A = $FF -ve, A = $01 +ve
A7A2 20 38 AE JSR $AE38 push sign, round FAC1 and put on stack
A7A5 A5 4A LDA $4A get FOR/NEXT variable pointer high byte
A7A7 48 PHA push on stack
A7A8 A5 49 LDA $49 get FOR/NEXT variable pointer low byte
A7AA 48 PHA push on stack
A7AB A9 81 LDA #$81 get FOR token
A7AD 48 PHA push on stack
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