libgcc/config/microblaze/umodsi3.S

   1 ###################################
   2 #
   3 #  Copyright (C) 2009-2024 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.S
  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 /* An executable stack is *not* required for these functions.  */
  36 #ifdef __linux__
  37 .section .note.GNU-stack,"",%progbits
  38 .previous
  39 #endif
  40
  41         .globl  __umodsi3
  42         .ent    __umodsi3
  43         .type   __umodsi3,@function
  44 __umodsi3:
  45         .frame  r1,0,r15
  46
  47         addik   r1,r1,-12
  48         swi     r29,r1,0
  49         swi     r30,r1,4
  50         swi     r31,r1,8
  51
  52         BEQI    r6,$LaDiv_By_Zero         # Div_by_Zero   # Division Error
  53         BEQId   r5,$LaResult_Is_Zero     # Result is Zero
  54         ADDIK   r3,r0,0                  # Clear div
  55         ADDIK   r30,r0,0        # clear mod
  56         ADDIK   r29,r0,32       # Initialize the loop count
  57
  58 # Check if r6 and r5 are equal # if yes, return 0
  59         rsub    r18,r5,r6
  60         beqi    r18,$LaRETURN_HERE
  61
  62 # Check if (uns)r6 is greater than (uns)r5. In that case, just return r5
  63         xor     r18,r5,r6
  64         bgeid   r18,16
  65         addik   r3,r5,0
  66         blti    r6,$LaRETURN_HERE
  67         bri     $LCheckr6
  68         rsub    r18,r5,r6 # MICROBLAZEcmp
  69         bgti    r18,$LaRETURN_HERE
  70
  71 # If r6 [bit 31] is set, then return result as r5-r6
  72 $LCheckr6:
  73         bgtid   r6,$LaDIV0
  74         addik   r3,r0,0
  75         addik   r18,r0,0x7fffffff
  76         and     r5,r5,r18
  77         and     r6,r6,r18
  78         brid    $LaRETURN_HERE
  79         rsub    r3,r6,r5
  80 # First part: try to find the first '1' in the r5
  81 $LaDIV0:
  82         BLTI    r5,$LaDIV2
  83 $LaDIV1:
  84         ADD     r5,r5,r5     # left shift logical r5
  85         BGEID   r5,$LaDIV1   #
  86         ADDIK   r29,r29,-1
  87 $LaDIV2:
  88         ADD     r5,r5,r5     # left shift logical  r5 get the '1' into the Carry
  89         ADDC    r3,r3,r3     # Move that bit into the Mod register
  90         rSUB    r31,r6,r3    # Try to subtract (r3 a r6)
  91         BLTi    r31,$LaMOD_TOO_SMALL
  92         OR      r3,r0,r31    # Move the r31 to mod since the result was positive
  93         ADDIK   r30,r30,1
  94 $LaMOD_TOO_SMALL:
  95         ADDIK   r29,r29,-1
  96         BEQi    r29,$LaLOOP_END
  97         ADD     r30,r30,r30 # Shift in the '1' into div
  98         BRI     $LaDIV2     # Div2
  99 $LaLOOP_END:
 100         BRI     $LaRETURN_HERE
 101 $LaDiv_By_Zero:
 102 $LaResult_Is_Zero:
 103         or      r3,r0,r0   # set result to 0
 104 $LaRETURN_HERE:
 105 # Restore values of CSRs and that of r3 and the divisor and the dividend
 106         lwi     r29,r1,0
 107         lwi     r30,r1,4
 108         lwi     r31,r1,8
 109         rtsd    r15,8
 110         addik   r1,r1,12
 111 .end __umodsi3
 112         .size   __umodsi3, . - __umodsi3