mirror of
https://github.com/cc65/cc65.git
synced 2024-08-18 10:29:06 +00:00
71 lines
2.0 KiB
ArmAsm
71 lines
2.0 KiB
ArmAsm
;
|
|
; Karri Kaksonen, Harry Dodgson 2006-01-07
|
|
;
|
|
; char cgetc (void);
|
|
;
|
|
|
|
.export _cgetc
|
|
.import _kbhit
|
|
.import KBEDG
|
|
.import KBSTL
|
|
|
|
; --------------------------------------------------------------------------
|
|
; The Atari Lynx has a very small keyboard - only 3 keys
|
|
; Opt1, Opt2 and Pause.
|
|
; But the designers have decided that pressing Pause and Opt1 at the
|
|
; same time means Restart and pressing Pause and Opt2 means Flip screen.
|
|
|
|
; For "easter egg" use I have also included all three keys pressed '?'
|
|
; and Opt1 + Opt2 pressed '3'.
|
|
; So the keyboard returns '1', '2', '3', 'P', 'R', 'F' or '?'.
|
|
|
|
_cgetc:
|
|
lda KBSTL
|
|
ora KBEDG
|
|
bne @L1
|
|
jsr _kbhit ; Check for char available
|
|
tax ; Test result
|
|
bra _cgetc
|
|
@L1:
|
|
ldx #0
|
|
and #1
|
|
beq @L6
|
|
lda KBEDG ; Pause button is pressed
|
|
and #$0c
|
|
beq @L3
|
|
ora KBSTL
|
|
@L2:
|
|
bit #$04
|
|
beq @L4 ; Pause + Opt 1 = Reset
|
|
bit #$08
|
|
beq @L5 ; Pause + Opt 2 = Flip
|
|
lda #'?' ; All buttons pressed
|
|
rts
|
|
@L3:
|
|
lda KBSTL ; Pause alone was the last placed button
|
|
and #$0c
|
|
bne @L2
|
|
lda #'P' ; Pause pressed
|
|
rts
|
|
@L4:
|
|
lda #'R' ; Reset pressed
|
|
rts
|
|
@L5:
|
|
lda #'F' ; Flip pressed
|
|
rts
|
|
@L6:
|
|
lda KBEDG ; No Pause pressed
|
|
ora KBSTL
|
|
bit #$08
|
|
beq @L8
|
|
bit #$04
|
|
beq @L7
|
|
lda #'3' ; opt 1 + opt 2 pressed
|
|
rts
|
|
@L7:
|
|
lda #'1' ; opt 1 pressed
|
|
rts
|
|
@L8:
|
|
lda #'2' ; opt 2 pressed
|
|
rts
|