mirror of
https://github.com/cc65/cc65.git
synced 2024-11-15 11:05:56 +00:00
160 lines
3.5 KiB
ArmAsm
160 lines
3.5 KiB
ArmAsm
;
|
|
; 2017-07-05, Greg King
|
|
; 2017-12-12, Groepaz
|
|
;
|
|
; void cpeeks (char* s, unsigned length);
|
|
;
|
|
|
|
.export _cpeeks
|
|
|
|
.import popax
|
|
.importzp ptr1, ptr2, ptr3, tmp1, tmp2
|
|
|
|
.macpack generic
|
|
|
|
; FIXME c128 needs special version that handles the 80-column VDC.
|
|
|
|
.include "c128.inc"
|
|
|
|
_cpeeks:
|
|
eor #<$FFFF ; counting a word upward is faster
|
|
sta ptr3 ; so, we use -(length + 1)
|
|
txa
|
|
eor #>$FFFF
|
|
sta ptr3+1
|
|
|
|
lda MODE
|
|
bmi c80
|
|
|
|
lda SCREEN_PTR
|
|
ldx SCREEN_PTR+1
|
|
sta ptr2
|
|
stx ptr2+1
|
|
ldy CURS_X
|
|
sty tmp2
|
|
|
|
jsr popax
|
|
sta tmp1 ; (will be a .Y index)
|
|
stx ptr1+1
|
|
ldx #<$0000
|
|
stx ptr1
|
|
bze L3 ; branch always
|
|
|
|
L4: ldy tmp2
|
|
lda (ptr2),y ; get char
|
|
iny
|
|
bnz L2
|
|
inc ptr2+1
|
|
L2: sty tmp2
|
|
and #<~$80 ; remove reverse bit
|
|
|
|
; Convert the screen code into a PetSCII code.
|
|
; $00 - $1F: +$40
|
|
; $20 - $3F
|
|
; $40 - $5f: +$20
|
|
; $60 - $7F: +$40
|
|
|
|
cmp #$20
|
|
blt @sk1 ;(bcc)
|
|
cmp #$40
|
|
blt L5
|
|
cmp #$60
|
|
blt @sk2 ;(bcc)
|
|
clc
|
|
@sk1: adc #$20
|
|
@sk2: ;clc ; both above cmp and adc clear carry flag
|
|
adc #$20
|
|
|
|
L5: ldy tmp1
|
|
sta (ptr1),y
|
|
iny
|
|
bnz L1
|
|
inc ptr1+1
|
|
L1: sty tmp1
|
|
|
|
L3: inc ptr3 ; count length
|
|
bnz L4
|
|
inc ptr3+1
|
|
bnz L4
|
|
|
|
txa ; terminate the string
|
|
ldy tmp1
|
|
sta (ptr1),y
|
|
rts
|
|
|
|
;-----------------------------------------------------------
|
|
c80:
|
|
lda SCREEN_PTR
|
|
clc
|
|
adc CURS_X
|
|
sta ptr2
|
|
lda SCREEN_PTR+1
|
|
adc #0
|
|
sta ptr2+1
|
|
|
|
jsr popax
|
|
sta tmp1 ; (will be a .Y index)
|
|
stx ptr1+1
|
|
ldx #<$0000
|
|
stx ptr1
|
|
bze L3a ; branch always
|
|
|
|
L4a:
|
|
lda ptr2
|
|
ldy ptr2+1
|
|
inc ptr2
|
|
bne @s
|
|
inc ptr2+1
|
|
@s:
|
|
; get byte from VDC mem
|
|
ldx #VDC_DATA_LO
|
|
stx VDC_INDEX
|
|
@L0: bit VDC_INDEX
|
|
bpl @L0
|
|
sta VDC_DATA
|
|
dex
|
|
stx VDC_INDEX
|
|
sty VDC_DATA
|
|
|
|
ldx #VDC_RAM_RW
|
|
stx VDC_INDEX
|
|
@L1: bit VDC_INDEX
|
|
bpl @L1 ; wait for blanking
|
|
lda VDC_DATA
|
|
|
|
and #<~$80 ; remove reverse bit
|
|
|
|
; Convert the screen code into a PetSCII code.
|
|
; $00 - $1F: +$40
|
|
; $20 - $3F
|
|
; $40 - $5f: +$20
|
|
; $60 - $7F: +$40
|
|
|
|
cmp #$20
|
|
blt @sk1 ;(bcc)
|
|
cmp #$40
|
|
blt L5a
|
|
cmp #$60
|
|
blt @sk2 ;(bcc)
|
|
clc
|
|
@sk1: adc #$20
|
|
@sk2: ;clc ; both above cmp and adc clear carry flag
|
|
adc #$20
|
|
|
|
L5a: ldy tmp1
|
|
sta (ptr1),y
|
|
iny
|
|
bnz L1a
|
|
inc ptr1+1
|
|
L1a: sty tmp1
|
|
|
|
L3a: inc ptr3 ; count length
|
|
bnz L4a
|
|
inc ptr3+1
|
|
bnz L4a
|
|
|
|
lda #0 ; terminate the string
|
|
ldy tmp1
|
|
sta (ptr1),y
|
|
rts
|