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;
; 2017-07-05, Greg King
;
; void cpeeks (char* s, unsigned length);
;
.export _cpeeks
.import popax
.importzp ptr1, ptr2, ptr3, tmp1, tmp2
.importzp CURS_X, CharPtr
.include "cbm610.inc"
.macpack generic
_cpeeks:
eor #<$FFFF ; counting a word upward is faster
sta ptr3 ; so, we use -(length + 1)
txa
eor #>$FFFF
sta ptr3+1
lda CharPtr
ldx CharPtr+1
sta ptr2
stx ptr2+1
ldy CURS_X
sty tmp2
jsr popax
sta tmp1 ; (will be a .Y index)
stx ptr1+1
ldx IndReg
ldy #<$0000
sty ptr1
bze L3 ; branch always
L4: ldy #$0F
sty IndReg
ldy tmp2
lda (ptr2),y ; get char from system bank
stx IndReg
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
lda #$00 ; terminate the string
ldy tmp1
sta (ptr1),y
rts
|
