emailler/client/ip65/string_utils.s

56 lines
979 B
ArmAsm

;text file parsing routines
.export parse_integer
.importzp copy_dest
.import mul_8_16
.importzp acc16
target_string=copy_dest
.include "../inc/common.i"
.bss
int_value: .res 2
.code
;parses a string, returns integer (up to 16 bits)
;inputs: AX points to a string containing an integer
;outputs: AX contains integer
parse_integer:
stax target_string
lda #0
sta int_value
sta int_value+1
tay
@parse_int:
lda (target_string),y
cmp #$30
bcc @end_of_int ;any non-decimal char should be treated as end of integer
cmp #$39
bcs @end_of_int ;any non-decimal char should be treated as end of integer
ldax int_value
stax acc16
lda #10
jsr mul_8_16
ldax acc16
stax int_value
lda (target_string),y
sec
sbc #'0'
clc
adc int_value
sta int_value
bcc @no_rollover
inc int_value+1
@no_rollover:
iny
bne @parse_int
@end_of_int:
ldax int_value
clc
rts