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cc65/libsrc/atari/mcbtxtchar.s
2022-04-17 16:06:22 +02:00

119 lines
2.8 KiB
ArmAsm

;
; Text mode character mouse callbacks for the Ataris
;
; Christian Groessler, 03.01.2014
;
; derived from Apple2 version by
; Oliver Schmidt, 22.09.2005
;
; All functions in this module should be interrupt safe, because they may
; be called from an interrupt handler
;
.export _mouse_txt_callbacks
.importzp tmp4
.import _mul40
.importzp mouse_txt_char ; screen code of mouse cursor
.include "atari.inc"
; ------------------------------------------------------------------------
.bss
backup: .res 1
visible:.res 1
; ------------------------------------------------------------------------
.segment "EXTZP" : zeropage
scrptr: .res 2
; ------------------------------------------------------------------------
.rodata
; Callback structure
_mouse_txt_callbacks:
.addr hide
.addr show
.addr prep
.addr draw
.addr movex
.addr movey
; ------------------------------------------------------------------------
.data
; setcursor
getcursor:
column: ldy #$00 ; Patched at runtime
lda (scrptr),y
rts
setcursor:
column2:ldy #$00 ; Patched at runtime
sta (scrptr),y
rts
; ------------------------------------------------------------------------
.code
done:
rts
; Hide the mouse cursor.
hide:
dec visible
prep:
jsr getcursor ; Get character at cursor position
cmp #mouse_txt_char ; "mouse" character
bne overwr ; no, probably program has overwritten it
lda backup ;
jmp setcursor ; Draw character
overwr: sta backup
rts
; Show the mouse cursor.
show:
inc visible
draw:
lda visible
beq done
jsr getcursor ; Cursor visible at current position?
sta backup ; Save character at cursor position
lda #mouse_txt_char
jmp setcursor ; Draw cursor
; Move the mouse cursor x position to the value in A/X.
movex:
cpx #1
ror a
lsr a ; convert to character position
lsr a
sta column+1
sta column2+1
rts
; Move the mouse cursor y position to the value in A/X.
movey:
ldy tmp4 ; mul40 uses tmp4, save in Y
lsr a ; convert y position to character line
lsr a
lsr a
jsr _mul40 ; carry is cleared by _mul40
adc SAVMSC
sta scrptr
txa
adc SAVMSC+1
sta scrptr+1
sty tmp4 ; restore tmp4
rts