sdcc/device/lib/mos6502/_strcmp.s

   1 ;-------------------------------------------------------------------------
   2 ;   _strcmp.s - standard C library function
   3 ;
   4 ;   Copyright (C) 1998, Ullrich von Bassewitz
   5 ;   Copyright (C) 2022, Gabriele Gorla
   6 ;
   7 ;   This library is free software; you can redistribute it and/or modify it
   8 ;   under the terms of the GNU General Public License as published by the
   9 ;   Free Software Foundation; either version 2, or (at your option) any
  10 ;   later version.
  11 ;
  12 ;   This library is distributed in the hope that it will be useful,
  13 ;   but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 ;   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 ;   GNU General Public License for more details.
  16 ;
  17 ;   You should have received a copy of the GNU General Public License
  18 ;   along with this library; see the file COPYING. If not, write to the
  19 ;   Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
  20 ;   MA 02110-1301, USA.
  21 ;
  22 ;   As a special exception, if you link this library with other files,
  23 ;   some of which are compiled with SDCC, to produce an executable,
  24 ;   this library does not by itself cause the resulting executable to
  25 ;   be covered by the GNU General Public License. This exception does
  26 ;   not however invalidate any other reasons why the executable file
  27 ;   might be covered by the GNU General Public License.
  28 ;-------------------------------------------------------------------------
  29
  30         .module _strcmp
  31
  32 ;--------------------------------------------------------
  33 ; exported symbols
  34 ;--------------------------------------------------------
  35         .globl _strcmp_PARM_2
  36         .globl _strcmp
  37
  38 ;--------------------------------------------------------
  39 ; overlayable function parameters in zero page
  40 ;--------------------------------------------------------
  41         .area   OSEG    (PAG, OVR)
  42 _strcmp_PARM_2:
  43         .ds 2
  44
  45 ;--------------------------------------------------------
  46 ; local aliases
  47 ;--------------------------------------------------------
  48         .define _str2 "_strcmp_PARM_2"
  49         .define _str1 "DPTR"
  50 ;--------------------------------------------------------
  51 ; code
  52 ;--------------------------------------------------------
  53         .area CODE
  54
  55 _strcmp:
  56         sta     *_str1+0
  57         stx     *_str1+1
  58
  59         ldy     #0
  60 loop:
  61         lda     [_str1],y
  62         cmp     [_str2],y
  63         bne     L1
  64         tax
  65         beq     end
  66         iny
  67         bne     loop
  68         inc     *_str1+1
  69         inc     *_str2+1
  70         bne     loop
  71 L1:
  72         bcs     L2
  73         ldx     #0xFF
  74 ;//     txa
  75         rts
  76 L2:
  77         ldx     #0x01
  78 ;//     txa
  79 end:
  80         rts