libgcc/config/epiphany/modsi3.S

   1 /* Signed 32 bit modulo optimized for Epiphany.
   2    Copyright (C) 2009-2024 Free Software Foundation, Inc.
   3    Contributed by Embecosm on behalf of Adapteva, Inc.
   4
   5 This file is part of GCC.
   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 This file is distributed in the hope that it will be useful, but
  13 WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15 General Public 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 #include "epiphany-asm.h"
  27
  28         FSTAB (__modsi3,T_INT)
  29         .global SYM(__modsi3)
  30         .balign 4
  31         HIDDEN_FUNC(__modsi3)
  32 SYM(__modsi3):
  33         asr r17,r0,31 ; save sign
  34         mov r2,0
  35         sub r3,r2,r0
  36         movgt r0,r3
  37         sub r3,r2,r1
  38         movgt r1,r3
  39         movt r2,0xa000 ; 0xa0000000
  40         orr r3,r2,r0
  41         lsr r15,r0,16
  42         movt r15,0xa800
  43         movne r3,r15
  44         lsr r16,r2,2 ; 0x28000000
  45         and r15,r3,r16
  46         fadd r12,r3,r15
  47          orr r3,r2,r1
  48         lsr r2,r1,16
  49         movt r2,0xa800
  50         movne r3,r2
  51         and r2,r16,r3
  52         fadd r3,r3,r2
  53          sub r2,r0,r1
  54         bltu .Lret_a
  55         lsr r12,r12,23
  56         mov r2,%low(.L0step)
  57         movt r2,%high(.L0step)
  58         lsr r3,r3,23
  59         sub r3,r12,r3 ; calculate bit number difference.
  60         lsl r3,r3,3
  61         sub r2,r2,r3
  62         jr r2
  63 /*              lsl_l r2,r1,n`               sub r2,r0,r2` movgteu r0,r2  */
  64 #define STEP(n) .long 0x0006441f | (n) << 5` sub r2,r0,r2` movgteu r0,r2
  65         .balign 8,,2
  66         STEP(31)` STEP(30)` STEP(29)` STEP(28)`
  67         STEP(27)` STEP(26)` STEP(25)` STEP(24)`
  68         STEP(23)` STEP(22)` STEP(21)` STEP(20)`
  69         STEP(19)` STEP(18)` STEP(17)` STEP(16)`
  70         STEP(15)` STEP(14)` STEP(13)` STEP(12)`
  71         STEP(11)` STEP(10)` STEP(9)`  STEP(8)`
  72         STEP(7)` STEP(6)` STEP(5)` STEP(4)` STEP(3)` STEP(2)` STEP(1)
  73 .L0step:STEP(0)
  74 .Lret_a:eor r0,r0,r17 ; restore sign
  75         sub r0,r0,r17
  76         rts
  77         ENDFUNC(__modsi3)