git.sur5r.net Git - cc65/blob - libsrc/geos/mousesprite/readjoy.s

   1 ;
   2 ; Ullrich von Bassewitz, 23.09.1998
   3 ;
   4 ; unsigned readjoy (unsigned char joy);
   5 ;
   6
   7         .export         _readjoy
   8
   9         .include        "../inc/geossym.inc"
  10
  11 .proc   _readjoy
  12
  13         php
  14         sei                     ; disable IRQ
  15         lda     $01
  16         pha
  17         lda     #$35
  18         sta     $01             ; enable I/O
  19
  20         tax                     ; Joystick number into X
  21         bne     joy2
  22
  23 ; Read joystick 1
  24
  25 joy1:
  26         lda     #$7F
  27         sta     cia1base
  28         lda     cia1base+1
  29 back:   tax
  30         pla
  31         sta     $01
  32         plp
  33         txa
  34         and     #$1F
  35         eor     #$1F
  36         ldx     #0
  37         rts
  38
  39 ; Read joystick 2
  40
  41 joy2:   lda     #$E0
  42         ldy     #$FF
  43         sta     cia1base+2
  44         lda     cia1base+1
  45         sty     cia1base+2
  46         jmp     back
  47
  48 .endproc