sdcc/device/lib/hc08/_mulint.c

   1 /*-------------------------------------------------------------------------
   2    _mulint.c - routine for (unsigned) int (16 bit) multiplication
   3
   4    Copyright (C) 1999, Sandeep Dutta . sandeep.dutta@usa.net
   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 /* Signed and unsigned multiplication are the same - as long as the output
  30    has the same precision as the input.
  31
  32    Assembler-functions are provided for:
  33      hc08
  34      hc08 stack-auto
  35 */
  36
  37
  38 #if !defined(_SDCC_NO_ASM_LIB_FUNCS)
  39
  40 #pragma save
  41 #pragma less_pedantic
  42 int
  43 _mulint (int a, int b)
  44 {
  45   a,b;  /* reference to make compiler happy */
  46
  47 #if !defined(__SDCC_STACK_AUTO)
  48     __asm
  49         ais #-2
  50         psha
  51         pshx
  52
  53         ldx __mulint_PARM_2+1
  54         mul
  55         sta 4,s
  56         stx 3,s
  57
  58         lda 1,s
  59         ldx __mulint_PARM_2+1
  60         mul
  61         add 3,s
  62         sta 3,s
  63
  64         lda 2,s
  65         ldx __mulint_PARM_2
  66         mul
  67         add 3,s
  68         sta 3,s
  69
  70         ais #2
  71         pulx
  72         pula
  73     __endasm;
  74 #else
  75     __asm
  76         ais #-2
  77         psha
  78         pshx
  79
  80         ldx 8,s
  81         mul
  82         sta 4,s
  83         stx 3,s
  84
  85         lda 1,s
  86         ldx 8,s
  87         mul
  88         add 3,s
  89         sta 3,s
  90
  91         lda 2,s
  92         ldx 7,s
  93         mul
  94         add 3,s
  95         sta 3,s
  96
  97         ais #2
  98         pulx
  99         pula
 100     __endasm;
 101 #endif
 102 }
 103 #pragma restore
 104
 105 #else
 106
 107 union uu {
 108         struct { unsigned char hi,lo ;} s;
 109         unsigned int t;
 110 } ;
 111
 112 int
 113 _mulint (int a, int b)
 114 {
 115 #if !defined(__SDCC_STACK_AUTO) && (defined(__SDCC_MODEL_LARGE) || defined(__SDCC_ds390))       // still needed for large
 116         union uu __xdata *x;
 117         union uu __xdata *y;
 118         union uu t;
 119         x = (union uu __xdata *)&a;
 120         y = (union uu __xdata *)&b;
 121 #else
 122         register union uu *x;
 123         register union uu *y;
 124         union uu t;
 125         x = (union uu *)&a;
 126         y = (union uu *)&b;
 127 #endif
 128
 129         t.t = x->s.lo * y->s.lo;
 130         t.s.hi += (x->s.lo * y->s.hi) + (x->s.hi * y->s.lo);
 131
 132        return t.t;
 133 }
 134 #endif
 135
 136
 137 #undef _MULINT_ASM
 138