libgcc/config/microblaze/umodsi3.asm

   1 ###################################
   2 #
   3 #  Copyright 2009, 2010 Free Software Foundation, Inc.
   4 #
   5 #  Contributed by Michael Eager <eager@eagercon.com>.
   6 #
   7 #  This file 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 3, or (at your option) any
  10 #  later version.
  11 #
  12 #  GCC is distributed in the hope that it will be useful, but WITHOUT
  13 #  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  14 #  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
  15 #  License for more details.
  16 #
  17 #  Under Section 7 of GPL version 3, you are granted additional
  18 #  permissions described in the GCC Runtime Library Exception, version
  19 #  3.1, as published by the Free Software Foundation.
  20 #
  21 #  You should have received a copy of the GNU General Public License and
  22 #  a copy of the GCC Runtime Library Exception along with this program;
  23 #  see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24 #  <http://www.gnu.org/licenses/>.
  25 #
  26 #  umodsi3.asm
  27 #
  28 #  Unsigned modulo operation for 32 bit integers.
  29 #       Input : op1 in Reg r5
  30 #               op2 in Reg r6
  31 #       Output: op1 mod op2 in Reg r3
  32 #
  33 #######################################
  34
  35         .globl  __umodsi3
  36         .ent    __umodsi3
  37         .type   __umodsi3,@function
  38 __umodsi3:
  39         .frame  r1,0,r15
  40
  41         addik   r1,r1,-12
  42         swi     r29,r1,0
  43         swi     r30,r1,4
  44         swi     r31,r1,8
  45
  46         BEQI    r6,$LaDiv_By_Zero         # Div_by_Zero   # Division Error
  47         BEQId   r5,$LaResult_Is_Zero     # Result is Zero
  48         ADDIK   r3,r0,0                  # Clear div
  49         ADDIK   r30,r0,0        # clear mod
  50         ADDIK   r29,r0,32       # Initialize the loop count
  51
  52 # Check if r6 and r5 are equal # if yes, return 0
  53         rsub    r18,r5,r6
  54         beqi    r18,$LaRETURN_HERE
  55
  56 # Check if (uns)r6 is greater than (uns)r5. In that case, just return r5
  57         xor     r18,r5,r6
  58         bgeid   r18,16
  59         addik   r3,r5,0
  60         blti    r6,$LaRETURN_HERE
  61         bri     $LCheckr6
  62         rsub    r18,r5,r6 # MICROBLAZEcmp
  63         bgti    r18,$LaRETURN_HERE
  64
  65 # If r6 [bit 31] is set, then return result as r5-r6
  66 $LCheckr6:
  67         bgtid   r6,$LaDIV0
  68         addik   r3,r0,0
  69         addik   r18,r0,0x7fffffff
  70         and     r5,r5,r18
  71         and     r6,r6,r18
  72         brid    $LaRETURN_HERE
  73         rsub    r3,r6,r5
  74 # First part: try to find the first '1' in the r5
  75 $LaDIV0:
  76         BLTI    r5,$LaDIV2
  77 $LaDIV1:
  78         ADD     r5,r5,r5     # left shift logical r5
  79         BGEID   r5,$LaDIV1   #
  80         ADDIK   r29,r29,-1
  81 $LaDIV2:
  82         ADD     r5,r5,r5     # left shift logical  r5 get the '1' into the Carry
  83         ADDC    r3,r3,r3     # Move that bit into the Mod register
  84         rSUB    r31,r6,r3    # Try to subtract (r3 a r6)
  85         BLTi    r31,$LaMOD_TOO_SMALL
  86         OR      r3,r0,r31    # Move the r31 to mod since the result was positive
  87         ADDIK   r30,r30,1
  88 $LaMOD_TOO_SMALL:
  89         ADDIK   r29,r29,-1
  90         BEQi    r29,$LaLOOP_END
  91         ADD     r30,r30,r30 # Shift in the '1' into div
  92         BRI     $LaDIV2     # Div2
  93 $LaLOOP_END:
  94         BRI     $LaRETURN_HERE
  95 $LaDiv_By_Zero:
  96 $LaResult_Is_Zero:
  97         or      r3,r0,r0   # set result to 0
  98 $LaRETURN_HERE:
  99 # Restore values of CSRs and that of r3 and the divisor and the dividend
 100         lwi     r29,r1,0
 101         lwi     r30,r1,4
 102         lwi     r31,r1,8
 103         rtsd    r15,8
 104         addik   r1,r1,12
 105 .end __umodsi3
 106         .size   __umodsi3, . - __umodsi3