mirror of
https://github.com/cc65/cc65.git
synced 2024-12-23 19:29:37 +00:00
94 lines
2.2 KiB
ArmAsm
94 lines
2.2 KiB
ArmAsm
;
|
|
; 2017-07-05, Greg King
|
|
;
|
|
; void cpeeks (char* s, unsigned length);
|
|
;
|
|
|
|
.export _cpeeks
|
|
|
|
.import popax
|
|
.importzp ptr1, ptr2, ptr3, tmp1, tmp2
|
|
|
|
.macpack generic
|
|
|
|
; Get a system-specific file.
|
|
; Note: The cbm610, and c128 targets need special
|
|
; versions that handle RAM banking and the 80-column VDC.
|
|
|
|
.if .def(__C16__)
|
|
.include "plus4.inc" ; both C16 and Plus4
|
|
.elseif .def(__C64__)
|
|
.include "c64.inc"
|
|
.elseif .def(__CBM510__)
|
|
.import CURS_X: zp, SCREEN_PTR: zp
|
|
.include "cbm510.inc"
|
|
.elseif .def(__PET__)
|
|
.include "pet.inc"
|
|
.elseif .def(__VIC20__)
|
|
.include "vic20.inc"
|
|
.endif
|
|
|
|
|
|
_cpeeks:
|
|
eor #<$FFFF ; counting a word upward is faster
|
|
sta ptr3 ; so, we use -(length + 1)
|
|
txa
|
|
eor #>$FFFF
|
|
sta ptr3+1
|
|
|
|
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
|