git.sur5r.net Git - cc65/blob - libsrc/cbm510/cgetc.s

   1 ;
   2 ; Ullrich von Bassewitz, 06.08.1998
   3 ;
   4 ; char cgetc (void);
   5 ;
   6
   7         .export         _cgetc
   8         .import         plot, write_crtc
   9         .import         cursor
  10
  11         .include        "zeropage.inc"
  12         .include        "page3.inc"
  13
  14
  15 ; ------------------------------------------------------------------------
  16
  17 .proc   _cgetc
  18
  19 L1:     lda     KeyIndex
  20         beq     L1
  21
  22 L2:     ldx     #$00            ; Get index
  23         ldy     KeyBuf          ; Get first character in the buffer
  24         sei
  25 L3:     lda     KeyBuf+1,x      ; Move up the remaining chars
  26         sta     KeyBuf,x
  27         inx
  28         cpx     KeyIndex
  29         bne     L3
  30         dec     KeyIndex
  31         cli
  32
  33         ldx     #$00            ; High byte
  34         tya                     ; First char from buffer
  35         rts
  36
  37 .endproc
  38