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cc65/libsrc/plus4/cgetc.s

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;
; Ullrich von Bassewitz, 06.08.1998
;
; char cgetc (void);
;
.export _cgetc
.import cursor
.include "plus4.inc"
_cgetc: lda KEY_COUNT ; Get number of characters
ora FKEY_COUNT ; Or with number of function key chars
bne L2 ; Jump if there are already chars waiting
; Switch on the cursor if needed
ldy CURS_X
lda (CRAM_PTR),y ; Get current char
pha ; And save it
lda CHARCOLOR
sta (CRAM_PTR),y
lda cursor
beq L1 ; Jump if no cursor
tya
clc
adc SCREEN_PTR
sta TED_CURSLO
lda SCREEN_PTR+1
adc #$00
sbc #$0B ; + carry = $C00 (screen address)
sta TED_CURSHI
L1: lda KEY_COUNT
ora FKEY_COUNT
beq L1
pla
sta (CRAM_PTR),y
lda #$ff
sta TED_CURSLO ; Cursor off
sta TED_CURSHI
L2: jsr KBDREAD ; Read char and return in A
ldx #0
rts