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cc65/libsrc/c128/cpeekrevers.s
2017-12-11 19:52:11 +01:00

52 lines
1.0 KiB
ArmAsm

;
; 2016-02-28, Groepaz
; 2017-06-26, Greg King
;
; unsigned char cpeekrevers (void);
;
.export _cpeekrevers
.include "zeropage.inc"
.include "c128.inc"
_cpeekrevers:
lda MODE
bmi @c80
ldy CURS_X
lda (SCREEN_PTR),y ; get char
@return:
and #$80 ; get reverse flag
asl a
tax ; ldx #>$0000
rol a ; return boolean value
rts
@c80:
lda SCREEN_PTR
ldy SCREEN_PTR+1
clc
adc CURS_X
bcc @s
iny
; get byte from VDC mem
@s: 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
jmp @return