sdcc/device/lib/mos6502/memcpy.s

   1 ;-------------------------------------------------------------------------
   2 ;   memcpy.s - standarc C library
   3 ;
   4 ;   Copyright (C) 2003, Ullrich von Bassewitz
   5 ;   Copyright (C) 2009, Christian Krueger
   6 ;   Copyright (C) 2022-2023, Gabriele Gorla
   7 ;
   8 ;   This library is free software; you can redistribute it and/or modify it
   9 ;   under the terms of the GNU General Public License as published by the
  10 ;   Free Software Foundation; either version 2, or (at your option) any
  11 ;   later version.
  12 ;
  13 ;   This library is distributed in the hope that it will be useful,
  14 ;   but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 ;   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 ;   GNU General Public License for more details.
  17 ;
  18 ;   You should have received a copy of the GNU General Public License
  19 ;   along with this library; see the file COPYING. If not, write to the
  20 ;   Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
  21 ;   MA 02110-1301, USA.
  22 ;
  23 ;   As a special exception, if you link this library with other files,
  24 ;   some of which are compiled with SDCC, to produce an executable,
  25 ;   this library does not by itself cause the resulting executable to
  26 ;   be covered by the GNU General Public License. This exception does
  27 ;   not however invalidate any other reasons why the executable file
  28 ;   might be covered by the GNU General Public License.
  29 ;-------------------------------------------------------------------------
  30
  31 ;       .module __memcpy
  32
  33 ;--------------------------------------------------------
  34 ; exported symbols
  35 ;--------------------------------------------------------
  36         .globl ___memcpy_PARM_2
  37         .globl ___memcpy_PARM_3
  38         .globl ___memcpy
  39         .globl _memcpy_PARM_2
  40         .globl _memcpy_PARM_3
  41         .globl _memcpy
  42
  43 ;--------------------------------------------------------
  44 ; overlayable function parameters in zero page
  45 ;--------------------------------------------------------
  46         .area   OSEG    (PAG, OVR)
  47 _memcpy_PARM_2:
  48 ___memcpy_PARM_2:
  49         .ds 2
  50 _memcpy_PARM_3:
  51 ___memcpy_PARM_3:
  52         .ds 2
  53
  54 ;--------------------------------------------------------
  55 ; local aliases
  56 ;--------------------------------------------------------
  57         .define save  "REGTEMP+0"
  58         .define dst   "DPTR"
  59         .define src   "___memcpy_PARM_2"
  60         .define count "___memcpy_PARM_3"
  61
  62 ;--------------------------------------------------------
  63 ; code
  64 ;--------------------------------------------------------
  65         .area CODE
  66
  67 _memcpy:
  68 ___memcpy:
  69         sta     *save+0
  70         stx     *save+1
  71         sta     *dst+0
  72         stx     *dst+1
  73
  74         ldy     #0
  75         ldx     *count+1
  76         beq     00002$
  77 00001$:
  78         lda     [src],y
  79         sta     [dst],y
  80         iny
  81         lda     [src],y
  82         sta     [dst],y
  83         iny
  84         bne     00001$
  85         inc     *src+1
  86         inc     *dst+1
  87         dex
  88         bne     00001$
  89 00002$:
  90         ldx     *count+0
  91         beq     00004$
  92 00003$:
  93         lda     [src],y
  94         sta     [dst],y
  95         iny
  96         dex
  97         bne     00003$
  98 00004$:
  99         lda     *save+0
 100         ldx     *save+1
 101         rts