AppleIIAsm-Collection/disks/disk5_strings/T.STR2NUM.MIN
nathanriggs 16c1731e54 Strings 0.2.0 update
- bugfixes
- implemented required library
- commenting updates
- .min of every routine
2018-12-22 20:35:05 -05:00

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*
STR2NUM
*
PLA
STA RETADR
PLA
STA RETADR+1
PLA
STA ADDR1
PLA
STA ADDR1+1
LDY #0
LDA (ADDR1),Y
TAX
LDA #1
STA :NINDEX
LDA #0
STA :NACCUM
STA :NACCUM+1
STA :SNGFLAG
TXA
BNE :INIT1
JMP :EREXIT
:INIT1
LDY :NINDEX
LDA (ADDR1),Y
CMP #173
BNE :PLUS
LDA #$0FF
STA :SNGFLAG
INC :NINDEX
DEX
BEQ :EREXIT
JMP :CNVERT
:PLUS
CMP #'+'
BNE :CHKDIG
INC :NINDEX
DEX
BEQ :EREXIT
:CNVERT
LDY :NINDEX
LDA (ADDR1),Y
:CHKDIG
CMP #$B0 ; "0"
BMI :EREXIT
CMP #$BA
BPL :EREXIT
PHA
ASL :NACCUM
ROL :NACCUM+1
LDA :NACCUM
LDY :NACCUM+1
ASL :NACCUM
ROL :NACCUM+1
ASL :NACCUM
ROL :NACCUM+1
CLC
ADC :NACCUM
STA :NACCUM
TYA
ADC :NACCUM+1
STA :NACCUM+1
PLA
SEC
SBC #$B0
CLC
ADC :NACCUM
STA :NACCUM
BCC :D2B1
INC :NACCUM+1
:D2B1
INC :NINDEX
DEX
BNE :CNVERT
LDA :SNGFLAG
BPL :OKEXIT
LDA #0
SEC
SBC :NACCUM
STA :NACCUM
LDA #0
SBC :NACCUM+1
STA :NACCUM+1
:OKEXIT
CLC
BCC :EXIT
:EREXIT
SEC
:EXIT
LDA RETADR+1
PHA
LDA RETADR
PHA
LDX :NACCUM+1
LDY :NACCUM
STY RETURN
STX RETURN+1
LDA #2
STA RETLEN
LDA :NINDEX
RTS
:NACCUM DS 2
:SNGFLAG DS 1
:NINDEX DS 1