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/* Copyright (C) 2008-2022 Free Software Foundation, Inc.
Contributor: Joern Rennecke <joern.rennecke@embecosm.com>
on behalf of Synopsys Inc.
This file is part of GCC.
GCC 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.
GCC 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/>. */
/* XMAC schedule: directly back-to-back multiplies stall; the third
instruction after a multiply stalls unless it is also a multiply. */
#include "arc-ieee-754.h"
#if 0 /* DEBUG */
.global __muldf3
.balign 4
__muldf3:
push_s blink
push_s r2
push_s r3
push_s r0
bl.d __muldf3_c
push_s r1
ld_s r2,[sp,12]
ld_s r3,[sp,8]
st_s r0,[sp,12]
st_s r1,[sp,8]
pop_s r1
bl.d __muldf3_asm
pop_s r0
pop_s r3
pop_s r2
pop_s blink
cmp r0,r2
cmp.eq r1,r3
jeq_s [blink]
b abort
#define __muldf3 __muldf3_asm
#endif /* DEBUG */
/* N.B. This is optimized for ARC700.
ARC600 has very different scheduling / instruction selection criteria. */
/* For the standard multiplier, instead of mpyu rx,DBL0L,DBL1L; tst rx,rx ,
we can do:
sub rx,DBL0L,1; bic rx,DBL0L,rx; lsr rx,rx; norm rx,rx; asl.f 0,DBL1L,rx */
__muldf3_support: /* This label makes debugger output saner. */
/* If one number is denormal, subtract some from the exponent of the other
one (if the other exponent is too small, return 0), and normalize the
denormal. Then re-run the computation. */
.balign 4
FUNC(__muldf3)
.Ldenorm_dbl0:
mov_s r12,DBL0L
mov_s DBL0L,DBL1L
mov_s DBL1L,r12
mov_s r12,DBL0H
mov_s DBL0H,DBL1H
mov_s DBL1H,r12
and r11,DBL0H,r9
.Ldenorm_dbl1:
brhs r11,r9,.Linf_nan
brhs 0x3ca00001,r11,.Lret0
sub_s DBL0H,DBL0H,DBL1H
bmsk_s DBL1H,DBL1H,30
add_s DBL0H,DBL0H,DBL1H
breq_s DBL1H,0,.Ldenorm_2
norm r12,DBL1H
sub_s r12,r12,10
asl r5,r12,20
asl_s DBL1H,DBL1H,r12
sub DBL0H,DBL0H,r5
neg r5,r12
lsr r6,DBL1L,r5
asl_s DBL1L,DBL1L,r12
b.d __muldf3
add_s DBL1H,DBL1H,r6
.balign 4
.Linf_nan:
bclr r12,DBL1H,31
xor_s DBL1H,DBL1H,DBL0H
bclr_s DBL0H,DBL0H,31
max r8,DBL0H,r12 ; either NaN -> NaN ; otherwise inf
or.f 0,DBL0H,DBL0L
mov_s DBL0L,0
or.ne.f DBL1L,DBL1L,r12
not_s DBL0H,DBL0L ; inf * 0 -> NaN
mov.ne DBL0H,r8
tst_s DBL1H,DBL1H
j_s.d [blink]
bset.mi DBL0H,DBL0H,31
.Lret0: xor_s DBL0H,DBL0H,DBL1H
bclr DBL1H,DBL0H,31
xor_s DBL0H,DBL0H,DBL1H
j_s.d [blink]
mov_l DBL0L,0
.balign 4
.Ldenorm_2:
breq_s DBL1L,0,.Lret0 ; 0 input -> 0 output
norm.f r12,DBL1L
mov.mi r12,21
add.pl r12,r12,22
neg r11,r12
asl_s r12,r12,20
lsr.f DBL1H,DBL1L,r11
ror DBL1L,DBL1L,r11
sub_s DBL0H,DBL0H,r12
mov.eq DBL1H,DBL1L
sub_s DBL1L,DBL1L,DBL1H
/* Fall through. */
.global __muldf3
.balign 4
__muldf3:
ld.as r9,[pcl,0x4b] ; ((.L7ff00000-.+2)/4)]
MPYHU r4,DBL0L,DBL1L
bmsk r6,DBL0H,19
bset r6,r6,20
mpyu r7,r6,DBL1L
and r11,DBL0H,r9
breq r11,0,.Ldenorm_dbl0
MPYHU r8,r6,DBL1L
bmsk r10,DBL1H,19
bset r10,r10,20
MPYHU r5,r10,DBL0L
add.f r4,r4,r7
and r12,DBL1H,r9
MPYHU r7,r6,r10
breq r12,0,.Ldenorm_dbl1
adc.f r5,r5,r8
mpyu r8,r10,DBL0L
breq r11,r9,.Linf_nan
breq r12,r9,.Linf_nan
mpyu r6,r6,r10
add.cs r7,r7,1
add.f r4,r4,r8
mpyu r10,DBL1L,DBL0L
bclr r8,r9,30 ; 0x3ff00000
adc.f r5,r5,r6
; XMAC write-back stall / std. mult stall is one cycle later
bclr r6,r9,20 ; 0x7fe00000
add.cs r7,r7,1 ; fraction product in r7:r5:r4
tst r10,r10
bset.ne r4,r4,0 ; put least significant word into sticky bit
lsr.f r10,r7,9
add_l r12,r12,r11 ; add exponents
rsub.eq r8,r8,r9 ; 0x40000000
sub r12,r12,r8 ; subtract bias + implicit 1
brhs.d r12,r6,.Linf_denorm
rsub r10,r10,12
.Lshift_frac:
neg r8,r10
asl r6,r4,r10
lsr DBL0L,r4,r8
add.f 0,r6,r6
btst.eq DBL0L,0
cmp.eq r4,r4 ; round to nearest / round to even
asl r4,r5,r10
lsr r5,r5,r8
adc.f DBL0L,DBL0L,r4
xor.f 0,DBL0H,DBL1H
asl r7,r7,r10
add_s r12,r12,r5
adc DBL0H,r12,r7
j_s.d [blink]
bset.mi DBL0H,DBL0H,31
/* We have checked for infinity / NaN input before, and transformed
denormalized inputs into normalized inputs. Thus, the worst case
exponent overflows are:
1 + 1 - 0x400 == 0xc02 : maximum underflow
0x7fe + 0x7fe - 0x3ff == 0xbfd ; maximum overflow
N.B. 0x7e and 0x7f are also values for overflow.
If (r12 <= -54), we have an underflow to zero. */
.balign 4
.Linf_denorm:
brlo r12,0xc0000000,.Linf
asr r6,r12,20
mov_s r12,0
add.f r10,r10,r6
brgt r10,0,.Lshift_frac
beq_s .Lround_frac
add.f r10,r10,32
.Lshift32_frac:
tst r4,r4
mov r4,r5
bset.ne r4,r4,1
mov r5,r7
mov r7,0
brge r10,1,.Lshift_frac
breq r10,0,.Lround_frac
add.f r10,r10,32
brgt r10,21,.Lshift32_frac
b_s .Lret0
.Lround_frac:
add.f 0,r4,r4
btst.eq r5,0
mov_s DBL0L,r5
mov_s DBL0H,r7
adc.eq.f DBL0L,DBL0L,0
j_s.d [blink]
adc.eq DBL0H,DBL0H,0
.Linf: xor.f DBL1H,DBL1H,DBL0H
mov_s DBL0L,0
mov_s DBL0H,r9
j_s.d [blink]
bset.mi DBL0H,DBL0H,31
ENDFUNC(__muldf3)
.balign 4
.L7ff00000:
.long 0x7ff00000