arch/m68k-all/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 "aros/m68k/asm.h"
  10
  11     .text
  12     .balign 4
  13
  14     .globl  AROS_SLIB_ENTRY(UDivMod32,Utility,26)
  15     .globl  AROS_SLIB_ENTRY(UDivMod32_020,Utility,26)
  16
  17     .type   AROS_SLIB_ENTRY(UDivMod32,Utility,26),@function
  18     .type   AROS_SLIB_ENTRY(UDivMod32_020,Utility,26),@function
  19
  20 AROS_SLIB_ENTRY(UDivMod32_020,Utility,26):
  21     divul.l %d1,%d1:%d0
  22     rts
  23
  24 /*
  25     This next algorithm is from the ixemul 41.0 source, the file
  26     ./ixemul-41.0/gnulib/common.h
  27 */
  28
  29     .balign 4
  30 AROS_SLIB_ENTRY(UDivMod32,Utility,26):
  31     movem.l %d2-%d3,-(%sp)
  32     cmp.l   #0xFFFF,%d1
  33     bhi.s   .Lfull_division
  34     move.l  %d1,%d3
  35     swap    %d0
  36     move.w  %d0,%d3
  37     beq.s   .Lsmall_division
  38     divu    %d1,%d3
  39     move.w  %d3,%d0
  40 .Lsmall_division:
  41     swap    %d0
  42     move.w  %d0,%d3
  43     divu    %d1,%d3
  44     move.w  %d3,%d0
  45     swap    %d3
  46     move.w  %d3,%d1
  47     movem.l (%sp)+,%d2-%d3
  48     rts
  49
  50 .Lfull_division:
  51     move.l  %d1,%d3
  52     move.l  %d0,%d1
  53     clr.w   %d1
  54     swap    %d0
  55     swap    %d1
  56     clr.w   %d0
  57     moveq   #0xF,%d2
  58 .Lloop:
  59     add.l   %d0,%d0
  60     addx.l  %d1,%d1
  61     cmp.l   %d1,%d3
  62     bhi.s   .Lloopend
  63     sub.l   %d3,%d1
  64     addq.w  #1,%d0
  65 .Lloopend:
  66     dbra    %d2,.Lloop
  67     movem.l (%sp)+,%d2-%d3
  68     rts