libgcc/config/microblaze/modsi3.S

   1 ###################################
   2 #
   3 #  Copyright (C) 2009-2023 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 #  modsi3.S
  27 #
  28 #  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  __modsi3
  42         .ent    __modsi3
  43         .type   __modsi3,@function
  44 __modsi3:
  45         .frame  r1,0,r15
  46
  47         addik   r1,r1,-16
  48         swi     r28,r1,0
  49         swi     r29,r1,4
  50         swi     r30,r1,8
  51         swi     r31,r1,12
  52
  53         BEQI    r6,$LaDiv_By_Zero       # Div_by_Zero   # Division Error
  54         BEQI    r5,$LaResult_Is_Zero    # Result is Zero
  55         BGEId   r5,$LaR5_Pos
  56         ADD     r28,r5,r0               # Get the sign of the result [ Depends only on the first arg]
  57         RSUBI   r5,r5,0                 # Make r5 positive
  58 $LaR5_Pos:
  59         BGEI    r6,$LaR6_Pos
  60         RSUBI   r6,r6,0     # Make r6 positive
  61 $LaR6_Pos:
  62         ADDIK   r3,r0,0      # Clear mod
  63         ADDIK   r30,r0,0     # clear div
  64         BLTId   r5,$LaDIV2   # If r5 is still negative (0x80000000), skip
  65                              # the first bit search.
  66         ADDIK   r29,r0,32    # Initialize the loop count
  67    # First part try to find the first '1' in the r5
  68 $LaDIV1:
  69         ADD     r5,r5,r5         # left shift logical r5
  70         BGEID   r5,$LaDIV1       #
  71         ADDIK   r29,r29,-1
  72 $LaDIV2:
  73         ADD     r5,r5,r5         # left shift logical  r5 get the '1' into the Carry
  74         ADDC    r3,r3,r3         # Move that bit into the Mod register
  75         rSUB    r31,r6,r3        # Try to subtract (r30 a r6)
  76         BLTi    r31,$LaMOD_TOO_SMALL
  77         OR      r3,r0,r31       # Move the r31 to mod since the result was positive
  78         ADDIK   r30,r30,1
  79 $LaMOD_TOO_SMALL:
  80         ADDIK   r29,r29,-1
  81         BEQi    r29,$LaLOOP_END
  82         ADD     r30,r30,r30         # Shift in the '1' into div
  83         BRI     $LaDIV2          # Div2
  84 $LaLOOP_END:
  85         BGEI    r28,$LaRETURN_HERE
  86         BRId    $LaRETURN_HERE
  87         rsubi   r3,r3,0 # Negate the result
  88 $LaDiv_By_Zero:
  89 $LaResult_Is_Zero:
  90         or      r3,r0,r0        # set result to 0 [Both mod as well as div are 0]
  91 $LaRETURN_HERE:
  92 # Restore values of CSRs and that of r3 and the divisor and the dividend
  93         lwi     r28,r1,0
  94         lwi     r29,r1,4
  95         lwi     r30,r1,8
  96         lwi     r31,r1,12
  97         rtsd    r15,8
  98         addik   r1,r1,16
  99         .end __modsi3
 100         .size   __modsi3, . - __modsi3
 101