libgcc/config/microblaze/divsi3.S

   1 ###################################-
   2 #
   3 #  Copyright (C) 2009-2020 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 #  divsi3.S
  27 #
  28 #  Divide operation for 32 bit integers.
  29 #       Input : Dividend in Reg r5
  30 #               Divisor in Reg r6
  31 #       Output: Result 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  __divsi3
  42         .ent    __divsi3
  43         .type   __divsi3,@function
  44 __divsi3:
  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         XOR     r28,r5,r6               # Get the sign of the result
  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   r30,r0,0                # Clear mod
  63         ADDIK   r3,r0,0                 # clear div
  64         ADDIK   r29,r0,32               # Initialize the loop count
  65
  66         # First part try to find the first '1' in the r5
  67 $LaDIV0:
  68         BLTI    r5,$LaDIV2              # This traps r5 == 0x80000000
  69 $LaDIV1:
  70         ADD     r5,r5,r5                # left shift logical r5
  71         BGTID   r5,$LaDIV1
  72         ADDIK   r29,r29,-1
  73 $LaDIV2:
  74         ADD     r5,r5,r5                # left shift logical  r5 get the '1' into the Carry
  75         ADDC    r30,r30,r30             # Move that bit into the Mod register
  76         RSUB    r31,r6,r30              # Try to subtract (r30 a r6)
  77         BLTI    r31,$LaMOD_TOO_SMALL
  78         OR      r30,r0,r31              # Move the r31 to mod since the result was positive
  79         ADDIK   r3,r3,1
  80 $LaMOD_TOO_SMALL:
  81         ADDIK   r29,r29,-1
  82         BEQi    r29,$LaLOOP_END
  83         ADD     r3,r3,r3                # Shift in the '1' into div
  84         BRI     $LaDIV2                 # Div2
  85 $LaLOOP_END:
  86         BGEI    r28,$LaRETURN_HERE
  87         BRID    $LaRETURN_HERE
  88         RSUBI   r3,r3,0                 # Negate the result
  89 $LaDiv_By_Zero:
  90 $LaResult_Is_Zero:
  91         OR      r3,r0,r0 # set result to 0
  92 $LaRETURN_HERE:
  93 # Restore values of CSRs and that of r3 and the divisor and the dividend
  94         LWI     r28,r1,0
  95         LWI     r29,r1,4
  96         LWI     r30,r1,8
  97         LWI     r31,r1,12
  98         RTSD    r15,8
  99         ADDIK   r1,r1,16
 100 .end __divsi3
 101         .size   __divsi3, . - __divsi3
 102