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/* Unsigned 32 bit division optimized for Epiphany.
Copyright (C) 2009-2021 Free Software Foundation, Inc.
Contributed by Embecosm on behalf of Adapteva, Inc.
This file is part of GCC.
This file is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 3, or (at your option) any
later version.
This file is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
#include "epiphany-asm.h"
FSTAB (__udivsi3,T_UINT)
.global SYM(__udivsi3)
.balign 4
HIDDEN_FUNC(__udivsi3)
SYM(__udivsi3):
sub TMP0,r0,r1
bltu .Lret0
float TMP2,r0
mov TMP1,%low(0xb0800000) ; ??? this would be faster with small data
float TMP3,r1
movt TMP1,%high(0xb0800000)
asr TMP0,r0,8
sub TMP0,TMP0,TMP1
movt TMP1,%high(0x00810000)
movgteu TMP2,TMP0
bblt .Lret1
sub TMP2,TMP2,TMP1
sub TMP2,TMP2,TMP3
mov TMP3,0
movltu TMP2,TMP3
lsr TMP2,TMP2,23
lsl r1,r1,TMP2
mov TMP0,1
lsl TMP0,TMP0,TMP2
sub r0,r0,r1
bltu .Ladd_back
add TMP3,TMP3,TMP0
sub r0,r0,r1
bltu .Ladd_back
.Lsub_loop:; More than two iterations are rare, so it makes sense to leave
; this label here to reduce average branch penalties.
add TMP3,TMP3,TMP0
sub r0,r0,r1
bgteu .Lsub_loop
.Ladd_back:
add r0,r0,r1
sub TMP1,r1,1
mov r1,%low(.L0step)
movt r1,%high(.L0step)
lsl TMP2,TMP2,3
sub r1,r1,TMP2
jr r1
.rep 30
lsl r0,r0,1
sub.l r1,r0,TMP1
movgteu r0,r1
.endr
.L0step:sub r1,TMP0,1 ; mask result bits from steps ...
and r0,r0,r1
orr r0,r0,TMP3 ; ... and combine with first bits.
rts
.Lret0: mov r0,0
rts
.Lret1: mov r0,1
rts
ENDFUNC(__udivsi3)