mirror of
https://github.com/cc65/cc65.git
synced 2024-11-01 11:04:34 +00:00
53dd513176
which included commits to RCS files with non-trunk default branches. git-svn-id: svn://svn.cc65.org/cc65/trunk@3 b7a2c559-68d2-44c3-8de9-860c34a00d81
59 lines
630 B
ArmAsm
59 lines
630 B
ArmAsm
;
|
|
; Ullrich von Bassewitz, 28.09.1998
|
|
;
|
|
; Write to the CRTC.
|
|
;
|
|
|
|
.export write_crtc, read_crtc
|
|
.importzp crtc
|
|
|
|
.include "cbm610.inc"
|
|
.include "zeropage.inc"
|
|
|
|
|
|
; Write a value to the CRTC. The index is in Y, the value in A
|
|
|
|
.proc write_crtc
|
|
sta sedt1
|
|
lda IndReg
|
|
pha
|
|
lda #$0F
|
|
sta IndReg
|
|
tya
|
|
ldy #$00
|
|
sei
|
|
sta (crtc),y
|
|
iny
|
|
lda sedt1
|
|
sta (crtc),y
|
|
cli
|
|
pla
|
|
sta IndReg
|
|
lda sedt1
|
|
rts
|
|
.endproc
|
|
|
|
|
|
.proc read_crtc
|
|
sty sedt1
|
|
lda IndReg
|
|
pha
|
|
lda #$0F
|
|
sta IndReg
|
|
lda sedt1
|
|
ldy #$00
|
|
sei
|
|
sta (crtc),y
|
|
iny
|
|
lda (crtc),y
|
|
cli
|
|
tay
|
|
pla
|
|
sta IndReg
|
|
tya
|
|
ldy sedt1
|
|
rts
|
|
.endproc
|
|
|
|
|