arch/.unmaintained/m68k-emul/utility/udivmod32.s

   1 /*
   2     Copyright © 1995-2001, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc: unsigned 32 bit division/modulus functions for Amiga/m68k
   6     Lang: english
   7 */
   8
   9 #include "machine.i"
  10
  11     .text
  12     .balign 16
  13     .globl  AROS_SLIB_ENTRY(UDivMod32,Utility)
  14     .globl  AROS_SLIB_ENTRY(UDivMod32_020,Utility)
  15
  16     .type   AROS_SLIB_ENTRY(UDivMod32,Utility),@function
  17     .type   AROS_SLIB_ENTRY(UDivMod32_020,Utility),@function
  18
  19 AROS_SLIB_ENTRY(UDivMod32_020,Utility):
  20     divul.l %d1,%d1:%d0
  21     rts
  22
  23 /*
  24     This next algorithm is from the ixemul 41.0 source, the file
  25     ./ixemul-41.0/gnulib/common.h
  26 */
  27
  28 AROS_SLIB_ENTRY(UDivMod32,Utility):
  29     movem.l  %d2-%d3,-(%sp)
  30     cmp.l   #0xFFFF,%d1
  31     jbhi    .full_division
  32     move.l  %d1,%d3
  33     swap    %d0
  34     move.w  %d0,%d3
  35     jbeq    .small_division
  36     divu    %d1,%d3
  37     move.w  %d3,%d0
  38 .small_division:
  39     swap    %d0
  40     move.w  %d0,%d3
  41     divu    %d1,%d3
  42     move.w  %d3,%d0
  43     swap    %d3
  44     move.w  %d3,%d1
  45     movem.l  (%sp)+,%d2-%d3
  46     rts
  47
  48 .full_division:
  49     move.l  %d1,%d3
  50     move.l  %d0,%d1
  51     clr.w   %d1
  52     swap    %d0
  53     swap    %d1
  54     clr.w   %d0
  55     moveq.l #0xF,%d2
  56 .loop:
  57     add.l   %d0,%d0
  58     addx.l  %d1,%d1
  59     cmp.l   %d1,%d3
  60     jbhi    .loopend
  61     sub.l   %d3,%d1
  62     addq.w  #1,%d0
  63 .loopend:
  64     dbra    %d2,.loop
  65     movem.l  (%sp)+,%d2-%d3
  66     rts