mirror of
https://github.com/cc65/cc65.git
synced 2024-11-04 17:04:58 +00:00
62 lines
1.1 KiB
ArmAsm
62 lines
1.1 KiB
ArmAsm
;
|
|
; Ullrich von Bassewitz, 06.08.1998
|
|
;
|
|
; char cgetc (void);
|
|
;
|
|
|
|
.export _cgetc
|
|
.import cursor
|
|
|
|
.include "vic20.inc"
|
|
|
|
_cgetc: lda KEY_COUNT ; Get number of characters
|
|
bne L3 ; Jump if there are already chars waiting
|
|
|
|
; Switch on the cursor if needed
|
|
|
|
lda CURS_FLAG
|
|
pha
|
|
lda cursor
|
|
jsr setcursor
|
|
L1: lda KEY_COUNT
|
|
beq L1
|
|
ldx #0
|
|
pla
|
|
bne L2
|
|
inx
|
|
L2: txa
|
|
jsr setcursor
|
|
|
|
L3: jsr KBDREAD ; Read char and return in A
|
|
ldx #0
|
|
rts
|
|
|
|
|
|
; Switch the cursor on or off
|
|
|
|
.proc setcursor
|
|
|
|
tax ; On or off?
|
|
bne seton ; Go set it on
|
|
lda CURS_FLAG ; Is the cursor currently off?
|
|
bne crs9 ; Jump if yes
|
|
lda #1
|
|
sta CURS_FLAG ; Mark it as off
|
|
lda CURS_STATE ; Cursor currently displayed?
|
|
beq crs8 ; Jump if no
|
|
ldy CURS_X ; Get the character column
|
|
lda (SCREEN_PTR),y ; Get character
|
|
eor #$80
|
|
sta (SCREEN_PTR),y ; Store character back
|
|
lda CURS_COLOR
|
|
sta (CRAM_PTR),y ; Store color back
|
|
crs8: lda #0
|
|
sta CURS_STATE ; Cursor not displayed
|
|
crs9: rts
|
|
|
|
seton: lda #0
|
|
sta CURS_FLAG
|
|
rts
|
|
|
|
.endproc
|