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cc65/libsrc/common/ltoa.s
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git-svn-id: svn://svn.cc65.org/cc65/trunk@3 b7a2c559-68d2-44c3-8de9-860c34a00d81
2000-05-28 13:40:48 +00:00

161 lines
2.4 KiB
ArmAsm

;
; Ullrich von Bassewitz, 11.06.1998
;
; char* ltoa (long value, char* s, int radix);
; char* ultoa (unsigned long value, char* s, int radix);
;
.export _ltoa, _ultoa
.import popax
.import __hextab
.importzp sreg, ptr1, ptr2, ptr3, tmp1
.rodata
specval:
.byte '-', '2', '1', '4', '7', '4', '8', '3', '6', '4', '8', 0
.code
;
; Common subroutine to pop the parameters and put them into core
;
dopop: sta tmp1 ; will loose high byte
jsr popax ; get s
sta ptr1
stx ptr1+1
sta sreg ; save for return
stx sreg+1
jsr popax ; get low word of value
sta ptr2
stx ptr2+1
jsr popax ; get high word of value
sta ptr3
stx ptr3+1
rts
;
; ltoa
;
_ltoa: jsr dopop ; pop the arguments
; We must handle $80000000 in a special way, since it is the only negative
; number that has no positive 32-bit counterpart
ldx ptr3+1 ; get high byte
ldy tmp1 ; get radix
cpy #10
bne ultoa
lda ptr3
ora ptr2+1
ora ptr2
bne L2
cpx #$80
bne L2
ldy #11
L1: lda specval,y ; copy -2147483648
sta (ptr1),y
dey
bpl L1
jmp L10
; Check if the value is negative. If so, write a - sign and negate the
; number.
L2: txa ; get high byte
bpl ultoa
lda #'-'
ldy #0
sta (ptr1),y ; store sign
inc ptr1
bne L3
inc ptr1+1
L3: lda ptr2 ; negate val
eor #$FF
clc
adc #$01
sta ptr2
lda ptr2+1
eor #$FF
adc #$00
sta ptr2+1
lda ptr3
eor #$FF
adc #$00
sta ptr3
lda ptr3+1
eor #$FF
adc #$00
sta ptr3+1
jmp ultoa
;
; utoa
;
_ultoa: jsr dopop ; pop the arguments
; Convert to string by dividing and push the result onto the stack
ultoa: lda #$00
pha ; sentinel
; Divide val/tmp1 -> val, remainder in a
L5: ldy #32 ; 32 bit
lda #0 ; remainder
L6: asl ptr2
rol ptr2+1
rol ptr3
rol ptr3+1
rol a
cmp tmp1
bcc L7
sbc tmp1
inc ptr2
L7: dey
bne L6
tay ; get remainder into y
lda __hextab,y ; get hex character
pha ; save char value on stack
lda ptr2
ora ptr2+1
ora ptr3
ora ptr3+1
bne L5
; Get the characters from the stack into the string
ldy #0
L9: pla
sta (ptr1),y
beq L10 ; jump if sentinel
iny
bne L9 ; jump always
; Done! Return the target string
L10: lda sreg
ldx sreg+1
rts