sdcc/device/lib/ds390/gptr_cmp.c

   1 /*-------------------------------------------------------------------------
   2 ;  gptr_cmp.asm - C run-time: compare two generic pointers
   3 ;
   4 ;  Copyright (C) 2011, Maarten Brock
   5 ;
   6 ;  This library is free software; you can redistribute it and/or modify it
   7 ;  under the terms of the GNU General Public License as published by the
   8 ;  Free Software Foundation; either version 2, or (at your option) any
   9 ;  later version.
  10 ;
  11 ;  This library is distributed in the hope that it will be useful,
  12 ;  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ;  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14 ;  GNU General Public License for more details.
  15 ;
  16 ;  You should have received a copy of the GNU General Public License
  17 ;  along with this library; see the file COPYING. If not, write to the
  18 ;  Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
  19 ;   MA 02110-1301, USA.
  20 ;
  21 ;  As a special exception, if you link this library with other files,
  22 ;  some of which are compiled with SDCC, to produce an executable,
  23 ;  this library does not by itself cause the resulting executable to
  24 ;  be covered by the GNU General Public License. This exception does
  25 ;  not however invalidate any other reasons why the executable file
  26 ;  might be covered by the GNU General Public License.
  27 ;------------------------------------------------------------------------*/
  28
  29 #ifdef __SDCC_MODEL_FLAT24
  30
  31 static void dummy(void) __naked
  32 {
  33         __asm
  34         .area HOME    (CODE)
  35
  36 ; compares two generic pointers.
  37 ; if p1 < p2  return NZ and C
  38 ; if p1 == p2 return  Z and NC
  39 ; if p1 > p2  return NZ and NC
  40 ; if both are a NULL pointer (yes, we have several) also return Z and NC
  41
  42 ___gptr_cmp::
  43     mov  a,sp
  44     add  a,#0xFA
  45     mov  dpl1,a
  46     mov  a,esp
  47     anl  a,#0x03
  48     addc a,#0xFF
  49     mov  dph1,a
  50     mov  dpx1,#0x40
  51     inc  dps        ;select dptr1
  52     movx a,@dptr
  53     mov  ap,a
  54     inc  dptr
  55     movx a,@dptr
  56     orl  ap,a
  57     inc  dptr
  58     movx a,@dptr
  59     orl  a,ap
  60     clr  c
  61     jnz  00001$
  62     mov  a,dpl
  63     orl  a,dph
  64     orl  a,dpx
  65 ; if both are NULL, return Z and NC
  66     jz   00002$
  67 00001$:
  68     orl  dps,#0x80  ;decrement dptr1
  69     inc  dptr
  70     inc  dptr
  71     anl  dps,#0x7F  ;increment dptr1
  72     movx a,@dptr
  73     subb a,dpl
  74     mov  ap,a
  75     inc  dptr
  76     movx a,@dptr
  77     subb a,dph
  78     orl  ap,a
  79     inc  dptr
  80     movx a,@dptr
  81     subb a,dpx
  82     orl  ap,a
  83     inc  dptr
  84     movx a,@dptr
  85     subb a,b
  86     orl  a,ap
  87 ; p2 < p1, return NZ and C
  88 ; p2 = p1, return Z and NC
  89 ; p2 > p1, return NZ and NC
  90 00002$:
  91     dec  dps        ;select dptr0
  92     ret
  93
  94         __endasm;
  95 }
  96
  97 #endif
  98