236 lines
5.5 KiB
ArmAsm
236 lines
5.5 KiB
ArmAsm
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/* Copyright (C) 2008-2021 Free Software Foundation, Inc.
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Contributor: Joern Rennecke <joern.rennecke@embecosm.com>
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on behalf of Synopsys Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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/* XMAC schedule: directly back-to-back multiplies stall; the third
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instruction after a multiply stalls unless it is also a multiply. */
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#include "arc-ieee-754.h"
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#if 0 /* DEBUG */
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.global __muldf3
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.balign 4
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__muldf3:
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push_s blink
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push_s r2
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push_s r3
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push_s r0
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bl.d __muldf3_c
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push_s r1
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ld_s r2,[sp,12]
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ld_s r3,[sp,8]
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st_s r0,[sp,12]
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st_s r1,[sp,8]
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pop_s r1
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bl.d __muldf3_asm
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pop_s r0
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pop_s r3
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pop_s r2
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pop_s blink
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cmp r0,r2
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cmp.eq r1,r3
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jeq_s [blink]
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b abort
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#define __muldf3 __muldf3_asm
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#endif /* DEBUG */
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/* N.B. This is optimized for ARC700.
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ARC600 has very different scheduling / instruction selection criteria. */
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/* For the standard multiplier, instead of mpyu rx,DBL0L,DBL1L; tst rx,rx ,
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we can do:
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sub rx,DBL0L,1; bic rx,DBL0L,rx; lsr rx,rx; norm rx,rx; asl.f 0,DBL1L,rx */
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__muldf3_support: /* This label makes debugger output saner. */
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/* If one number is denormal, subtract some from the exponent of the other
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one (if the other exponent is too small, return 0), and normalize the
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denormal. Then re-run the computation. */
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.balign 4
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FUNC(__muldf3)
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.Ldenorm_dbl0:
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mov_s r12,DBL0L
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mov_s DBL0L,DBL1L
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mov_s DBL1L,r12
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mov_s r12,DBL0H
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mov_s DBL0H,DBL1H
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mov_s DBL1H,r12
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and r11,DBL0H,r9
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.Ldenorm_dbl1:
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brhs r11,r9,.Linf_nan
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brhs 0x3ca00001,r11,.Lret0
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sub_s DBL0H,DBL0H,DBL1H
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bmsk_s DBL1H,DBL1H,30
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add_s DBL0H,DBL0H,DBL1H
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breq_s DBL1H,0,.Ldenorm_2
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norm r12,DBL1H
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sub_s r12,r12,10
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asl r5,r12,20
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asl_s DBL1H,DBL1H,r12
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sub DBL0H,DBL0H,r5
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neg r5,r12
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lsr r6,DBL1L,r5
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asl_s DBL1L,DBL1L,r12
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b.d __muldf3
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add_s DBL1H,DBL1H,r6
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.balign 4
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.Linf_nan:
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bclr r12,DBL1H,31
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xor_s DBL1H,DBL1H,DBL0H
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bclr_s DBL0H,DBL0H,31
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max r8,DBL0H,r12 ; either NaN -> NaN ; otherwise inf
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or.f 0,DBL0H,DBL0L
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mov_s DBL0L,0
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or.ne.f DBL1L,DBL1L,r12
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not_s DBL0H,DBL0L ; inf * 0 -> NaN
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mov.ne DBL0H,r8
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tst_s DBL1H,DBL1H
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j_s.d [blink]
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bset.mi DBL0H,DBL0H,31
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.Lret0: xor_s DBL0H,DBL0H,DBL1H
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bclr DBL1H,DBL0H,31
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xor_s DBL0H,DBL0H,DBL1H
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j_s.d [blink]
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mov_l DBL0L,0
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.balign 4
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.Ldenorm_2:
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breq_s DBL1L,0,.Lret0 ; 0 input -> 0 output
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norm.f r12,DBL1L
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mov.mi r12,21
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add.pl r12,r12,22
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neg r11,r12
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asl_s r12,r12,20
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lsr.f DBL1H,DBL1L,r11
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ror DBL1L,DBL1L,r11
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sub_s DBL0H,DBL0H,r12
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mov.eq DBL1H,DBL1L
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sub_s DBL1L,DBL1L,DBL1H
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/* Fall through. */
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.global __muldf3
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.balign 4
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__muldf3:
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ld.as r9,[pcl,0x4b] ; ((.L7ff00000-.+2)/4)]
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MPYHU r4,DBL0L,DBL1L
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bmsk r6,DBL0H,19
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bset r6,r6,20
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mpyu r7,r6,DBL1L
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and r11,DBL0H,r9
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breq r11,0,.Ldenorm_dbl0
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MPYHU r8,r6,DBL1L
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bmsk r10,DBL1H,19
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bset r10,r10,20
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MPYHU r5,r10,DBL0L
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add.f r4,r4,r7
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and r12,DBL1H,r9
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MPYHU r7,r6,r10
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breq r12,0,.Ldenorm_dbl1
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adc.f r5,r5,r8
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mpyu r8,r10,DBL0L
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breq r11,r9,.Linf_nan
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breq r12,r9,.Linf_nan
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mpyu r6,r6,r10
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add.cs r7,r7,1
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add.f r4,r4,r8
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mpyu r10,DBL1L,DBL0L
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bclr r8,r9,30 ; 0x3ff00000
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adc.f r5,r5,r6
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; XMAC write-back stall / std. mult stall is one cycle later
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bclr r6,r9,20 ; 0x7fe00000
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add.cs r7,r7,1 ; fraction product in r7:r5:r4
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tst r10,r10
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bset.ne r4,r4,0 ; put least significant word into sticky bit
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lsr.f r10,r7,9
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add_l r12,r12,r11 ; add exponents
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rsub.eq r8,r8,r9 ; 0x40000000
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sub r12,r12,r8 ; subtract bias + implicit 1
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brhs.d r12,r6,.Linf_denorm
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rsub r10,r10,12
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.Lshift_frac:
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neg r8,r10
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asl r6,r4,r10
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lsr DBL0L,r4,r8
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add.f 0,r6,r6
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btst.eq DBL0L,0
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cmp.eq r4,r4 ; round to nearest / round to even
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asl r4,r5,r10
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lsr r5,r5,r8
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adc.f DBL0L,DBL0L,r4
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xor.f 0,DBL0H,DBL1H
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asl r7,r7,r10
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add_s r12,r12,r5
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adc DBL0H,r12,r7
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j_s.d [blink]
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bset.mi DBL0H,DBL0H,31
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/* We have checked for infinity / NaN input before, and transformed
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denormalized inputs into normalized inputs. Thus, the worst case
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exponent overflows are:
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1 + 1 - 0x400 == 0xc02 : maximum underflow
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0x7fe + 0x7fe - 0x3ff == 0xbfd ; maximum overflow
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N.B. 0x7e and 0x7f are also values for overflow.
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If (r12 <= -54), we have an underflow to zero. */
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.balign 4
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.Linf_denorm:
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brlo r12,0xc0000000,.Linf
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asr r6,r12,20
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mov_s r12,0
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add.f r10,r10,r6
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brgt r10,0,.Lshift_frac
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beq_s .Lround_frac
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add.f r10,r10,32
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.Lshift32_frac:
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tst r4,r4
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mov r4,r5
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bset.ne r4,r4,1
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mov r5,r7
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mov r7,0
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brge r10,1,.Lshift_frac
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breq r10,0,.Lround_frac
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add.f r10,r10,32
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brgt r10,21,.Lshift32_frac
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b_s .Lret0
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.Lround_frac:
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add.f 0,r4,r4
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btst.eq r5,0
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mov_s DBL0L,r5
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mov_s DBL0H,r7
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adc.eq.f DBL0L,DBL0L,0
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j_s.d [blink]
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adc.eq DBL0H,DBL0H,0
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.Linf: xor.f DBL1H,DBL1H,DBL0H
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mov_s DBL0L,0
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mov_s DBL0H,r9
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j_s.d [blink]
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bset.mi DBL0H,DBL0H,31
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ENDFUNC(__muldf3)
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.balign 4
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.L7ff00000:
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.long 0x7ff00000
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