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https://github.com/autc04/Retro68.git
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525 lines
12 KiB
ArmAsm
525 lines
12 KiB
ArmAsm
/* Copyright (C) 2008-2017 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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#include "arc-ieee-754.h"
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#if 0 /* DEBUG */
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.global __adddf3
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.balign 4
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__adddf3:
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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 __adddf3_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 __adddf3_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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bl abort
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.global __subdf3
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.balign 4
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__subdf3:
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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 __subdf3_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 __subdf3_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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bl abort
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#define __adddf3 __adddf3_asm
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#define __subdf3 __subdf3_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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/* inputs: DBL0, DBL1 (r0-r3)
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output: DBL0 (r0, r1)
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clobber: r2-r10, r12, flags
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All NaN highword bits must be 1. NaN low word is random. */
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.balign 4
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.global __adddf3
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.global __subdf3
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.long 0x7ff00000 ; exponent mask
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FUNC(__adddf3)
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FUNC(__subdf3)
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__subdf3:
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bxor_l DBL1H,DBL1H,31
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__adddf3:
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ld r9,[pcl,-8]
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bmsk r4,DBL0H,30
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xor r10,DBL0H,DBL1H
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and r6,DBL1H,r9
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sub.f r12,r4,r6
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asr_s r12,r12,20
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blo .Ldbl1_gt
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brhs r4,r9,.Linf_nan
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brhs r12,32,.Large_shift
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brne r12,0,.Lsmall_shift
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brge r10,0,.Ladd_same_exp ; r12 == 0
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/* After subtracting, we need to normalize; when shifting to place the
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leading 1 into position for the implicit 1 and adding that to DBL0H,
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we increment the exponent. Thus, we have to subtract one more than
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the shift count from the exponent beforehand. Iff the exponent drops thus
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below zero (before adding in the fraction with the leading one), we have
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generated a denormal number. Denormal handling is basicallly reducing the
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shift count so that we produce a zero exponent instead; however, this way
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the shift count can become zero (if we started out with exponent 1).
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Therefore, a simple min operation is not good enough, since we don't
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want to handle a zero normalizing shift in the main path.
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On the plus side, we don't need to check for denorm input, the result
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of subtracing these looks just the same as denormals generated during
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subtraction. */
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bmsk r7,DBL1H,30
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cmp r4,r7
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cmp.eq DBL0L,DBL1L
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blo .L_rsub_same_exp
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sub.f DBL0L,DBL0L,DBL1L
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bmsk r12,DBL0H,19
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bic DBL1H,DBL0H,r12
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sbc.f r4,r4,r7
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beq_l .Large_cancel
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norm DBL1L,r4
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b.d .Lsub_done_same_exp
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sub r12,DBL1L,9
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.balign 4
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.Linf_nan:
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; If both inputs are inf, but with different signs, the result is NaN.
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asr r12,r10,31
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or_s DBL1H,DBL1H,r12
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j_s.d [blink]
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or.eq DBL0H,DBL0H,DBL1H
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.balign 4
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.L_rsub_same_exp:
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rsub.f DBL0L,DBL0L,DBL1L
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bmsk r12,DBL1H,19
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bic_s DBL1H,DBL1H,r12
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sbc.f r4,r7,r4
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beq_l .Large_cancel
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norm DBL1L,r4
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sub r12,DBL1L,9
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.Lsub_done_same_exp:
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asl_s r12,r12,20
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sub_s DBL1L,DBL1L,10
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sub DBL0H,DBL1H,r12
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xor.f 0,DBL0H,DBL1H
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bmi .Ldenorm
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.Lpast_denorm:
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neg_s r12,DBL1L
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lsr r7,DBL0L,r12
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asl r12,r4,DBL1L
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asl_s DBL0L,DBL0L,DBL1L
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add_s r12,r12,r7
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j_s.d [blink]
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add_l DBL0H,DBL0H,r12
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.balign 4
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.Ladd_same_exp:
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/* This is a special case because we can't test for need to shift
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down by checking if bit 20 of DBL0H changes. OTOH, here we know
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that we always need to shift down. */
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; The implicit 1 of DBL0 is not shifted together with the
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; fraction, thus effectively doubled, compensating for not setting
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; implicit1 for DBL1
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add_s r12,DBL0L,DBL1L
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lsr.f 0,r12,2 ; round to even
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breq r6,0,.Ldenorm_add
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adc.f DBL0L,DBL0L,DBL1L
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sub r7,DBL1H,DBL0H
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sub1 r7,r7,r9 ; boost exponent by 2/2
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rrc DBL0L,DBL0L
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asr.f r7,r7 ; DBL1.fraction/2 - DBL0.fraction/2 ; exp++
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add.cs.f DBL0L,DBL0L,0x80000000
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add_l DBL0H,DBL0H,r7 ; DBL0.implicit1 not shifted for DBL1.implicit1
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add.cs DBL0H,DBL0H,1
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bic.f 0,r9,DBL0H ; check for overflow -> infinity.
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jne_l [blink]
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and DBL0H,DBL0H,0xfff00000
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j_s.d [blink]
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mov_s DBL0L,0
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.balign 4
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.Large_shift:
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brhs r12,55,.Lret_dbl0
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bmsk_s DBL1H,DBL1H,19
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brne r6,0,.Lno_denorm_large_shift
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brhi.d r12,33,.Lfixed_denorm_large_shift
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sub_s r12,r12,1
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breq r12,31, .Lfixed_denorm_small_shift
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.Lshift32:
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mov_s r12,DBL1L
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mov_s DBL1L,DBL1H
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brlt.d r10,0,.Lsub
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mov_s DBL1H,0
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b_s .Ladd
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.Ldenorm_add:
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cmp_s r12,DBL1L
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mov_s DBL0L,r12
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j_s.d [blink]
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adc DBL0H,r4,DBL1H
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.Lret_dbl0:
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j_s [blink]
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.balign 4
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.Lsmall_shift:
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breq.d r6,0,.Ldenorm_small_shift
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bmsk_s DBL1H,DBL1H,19
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bset_s DBL1H,DBL1H,20
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.Lfixed_denorm_small_shift:
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neg r8,r12
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asl r4,DBL1H,r8
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lsr_l DBL1H,DBL1H,r12
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lsr r5,DBL1L,r12
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asl r12,DBL1L,r8
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brge.d r10,0,.Ladd
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or DBL1L,r4,r5
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/* subtract, abs(DBL0) > abs(DBL1) */
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/* DBL0H, DBL0L: original values
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DBL1H, DBL1L: fraction with explicit leading 1, shifted into place
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r4: orig. DBL0H & 0x7fffffff
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r6: orig. DBL1H & 0x7ff00000
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r9: 0x7ff00000
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r10: orig. DBL0H ^ DBL1H
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r12: guard bits */
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.balign 4
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.Lsub:
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neg.f r12,r12
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mov_s r7,DBL1H
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bmsk r5,DBL0H,19
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sbc.f DBL0L,DBL0L,DBL1L
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bic DBL1H,DBL0H,r5
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bset r5,r5,20
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sbc.f r4,r5,r7
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beq_l .Large_cancel_sub
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norm DBL1L,r4
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bmsk r6,DBL1H,30
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.Lsub_done:
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sub_s DBL1L,DBL1L,9
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breq DBL1L,1,.Lsub_done_noshift
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asl r5,DBL1L,20
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sub_s DBL1L,DBL1L,1
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brlo r6,r5,.Ldenorm_sub
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sub DBL0H,DBL1H,r5
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.Lpast_denorm_sub:
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neg_s DBL1H,DBL1L
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lsr r6,r12,DBL1H
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asl_s r12,r12,DBL1L
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and r8,r6,1
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add1.f 0,r8,r12
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add.ne.f r12,r12,r12
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asl r8,DBL0L,DBL1L
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lsr r12,DBL0L,DBL1H
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adc.f DBL0L,r8,r6
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asl r5,r4,DBL1L
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add_s DBL0H,DBL0H,r12
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j_s.d [blink]
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adc DBL0H,DBL0H,r5
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.balign 4
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.Lno_denorm_large_shift:
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breq.d r12,32,.Lshift32
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bset_l DBL1H,DBL1H,20
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.Lfixed_denorm_large_shift:
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neg r8,r12
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asl r4,DBL1H,r8
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lsr r5,DBL1L,r12
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asl.f 0,DBL1L,r8
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lsr DBL1L,DBL1H,r12
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or r12,r4,r5
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tst.eq r12,1
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or.ne r12,r12,2
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brlt.d r10,0,.Lsub
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mov_s DBL1H,0
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b_l .Ladd
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; If a denorm is produced without shifting, we have an exact result -
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; no need for rounding.
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.balign 4
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.Ldenorm_sub:
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lsr DBL1L,r6,20
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xor DBL0H,r6,DBL1H
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brne.d DBL1L,1,.Lpast_denorm_sub
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sub_s DBL1L,DBL1L,1
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.Lsub_done_noshift:
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add.f 0,r12,r12
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btst.eq DBL0L,0
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cmp.eq r12,r12
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add.cs.f DBL0L,DBL0L,1
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bclr r4,r4,20
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j_s.d [blink]
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adc DBL0H,DBL1H,r4
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.balign 4
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.Ldenorm_small_shift:
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brne.d r12,1,.Lfixed_denorm_small_shift
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sub_l r12,r12,1
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brlt r10,0,.Lsub
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.Ladd: ; bit 20 of DBL1H is clear and bit 0 of r12 does not matter
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add.f DBL0L,DBL0L,DBL1L
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add_s DBL1H,DBL1H,DBL0H
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add.cs DBL1H,DBL1H,1
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xor_l DBL0H,DBL0H,DBL1H
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bbit0 DBL0H,20,.Lno_shiftdown
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lsr.f DBL0H,DBL1H
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and r4,DBL0L,2
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bmsk DBL0H,DBL0H,18
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sbc DBL0H,DBL1H,DBL0H
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rrc.f DBL0L,DBL0L
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or.f r12,r12,r4
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cmp.eq r12,r12
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add.cs.f DBL0L,DBL0L,1
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bic.f 0,r9,DBL0H ; check for generating infinity with possible ...
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jne.d [blink] ; ... non-zero fraction
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add.cs DBL0H,DBL0H,1
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mov_s DBL0L,0
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bmsk DBL1H,DBL0H,19
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j_s.d [blink]
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bic_s DBL0H,DBL0H,DBL1H
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.Lno_shiftdown:
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mov_s DBL0H,DBL1H
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add.f 0,r12,r12
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btst.eq DBL0L,0
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cmp.eq r12,r12
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add.cs.f DBL0L,DBL0L,1
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j_s.d [blink]
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add.cs DBL0H,DBL0H,1
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.balign 4
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.Ldenorm:
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bmsk DBL0H,DBL1H,30
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lsr r12,DBL0H,20
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xor_s DBL0H,DBL0H,DBL1H
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sub_l DBL1L,r12,1
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bgt .Lpast_denorm
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j_s.d [blink]
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add_l DBL0H,DBL0H,r4
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.balign 4
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.Large_cancel:
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;DBL0L: mantissa DBL1H: sign & exponent
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norm.f DBL1L,DBL0L
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bmsk DBL0H,DBL1H,30
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add_s DBL1L,DBL1L,22
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mov.mi DBL1L,21
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add_s r12,DBL1L,1
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asl_s r12,r12,20
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beq_s .Lret0
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brhs.d DBL0H,r12,.Lpast_denorm_large_cancel
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sub DBL0H,DBL1H,r12
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bmsk DBL0H,DBL1H,30
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lsr r12,DBL0H,20
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xor_s DBL0H,DBL0H,DBL1H
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sub.f DBL1L,r12,1
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jle [blink]
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.Lpast_denorm_large_cancel:
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rsub.f r7,DBL1L,32
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lsr r7,DBL0L,r7
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asl_s DBL0L,DBL0L,DBL1L
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mov.ls r7,DBL0L
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add_s DBL0H,DBL0H,r7
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j_s.d [blink]
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mov.ls DBL0L,0
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.Lret0:
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j_s.d [blink]
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mov_l DBL0H,0
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/* r4:DBL0L:r12 : unnormalized result fraction
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DBL1H: result sign and exponent */
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/* When seeing large cancellation, only the topmost guard bit might be set. */
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.balign 4
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.Large_cancel_sub:
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norm.f DBL1L,DBL0L
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bpnz.d 0f
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bmsk DBL0H,DBL1H,30
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mov r5,22<<20
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bne.d 1f
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mov_s DBL1L,21
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bset r5,r5,5+20
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add_s DBL1L,DBL1L,32
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brne r12,0,1f
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j_s.d [blink]
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mov_l DBL0H,0
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.balign 4
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0: add r5,DBL1L,23
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asl r5,r5,20
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add_s DBL1L,DBL1L,22
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1: brlo DBL0H,r5,.Ldenorm_large_cancel_sub
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sub DBL0H,DBL1H,r5
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.Lpast_denorm_large_cancel_sub:
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rsub.f r7,DBL1L,32
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lsr r12,r12,r7
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lsr r7,DBL0L,r7
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asl_s DBL0L,DBL0L,DBL1L
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add.ge DBL0H,DBL0H,r7
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add_s DBL0L,DBL0L,r12
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add.lt DBL0H,DBL0H,DBL0L
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mov.eq DBL0L,r12
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j_s.d [blink]
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mov.lt DBL0L,0
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.balign 4
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.Ldenorm_large_cancel_sub:
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lsr r5,DBL0H,20
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xor_s DBL0H,DBL0H,DBL1H
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brgt.d r5,1,.Lpast_denorm_large_cancel_sub
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sub DBL1L,r5,1
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j_l [blink] ; denorm, no shift -> no rounding needed.
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/* r4: DBL0H & 0x7fffffff
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r6: DBL1H & 0x7ff00000
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r9: 0x7ff00000
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r10: sign difference
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r12: shift count (negative) */
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.balign 4
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.Ldbl1_gt:
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brhs r6,r9,.Lret_dbl1 ; inf or NaN
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neg r8,r12
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brhs r8,32,.Large_shift_dbl0
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.Lsmall_shift_dbl0:
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breq.d r6,0,.Ldenorm_small_shift_dbl0
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bmsk_s DBL0H,DBL0H,19
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bset_s DBL0H,DBL0H,20
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.Lfixed_denorm_small_shift_dbl0:
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asl r4,DBL0H,r12
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lsr DBL0H,DBL0H,r8
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lsr r5,DBL0L,r8
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asl r12,DBL0L,r12
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brge.d r10,0,.Ladd_dbl1_gt
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or DBL0L,r4,r5
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/* subtract, abs(DBL0) < abs(DBL1) */
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/* DBL0H, DBL0L: fraction with explicit leading 1, shifted into place
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DBL1H, DBL1L: original values
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r6: orig. DBL1H & 0x7ff00000
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|
r9: 0x7ff00000
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|
r12: guard bits */
|
|
.balign 4
|
|
.Lrsub:
|
|
neg.f r12,r12
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|
bmsk r7,DBL1H,19
|
|
mov_s r5,DBL0H
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|
sbc.f DBL0L,DBL1L,DBL0L
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|
bic DBL1H,DBL1H,r7
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|
bset r7,r7,20
|
|
sbc.f r4,r7,r5
|
|
beq_l .Large_cancel_sub
|
|
norm DBL1L,r4
|
|
b_l .Lsub_done ; note: r6 is already set up.
|
|
|
|
.Lret_dbl1:
|
|
mov_s DBL0H,DBL1H
|
|
j_s.d [blink]
|
|
mov_l DBL0L,DBL1L
|
|
.balign 4
|
|
.Ldenorm_small_shift_dbl0:
|
|
sub.f r8,r8,1
|
|
bne.d .Lfixed_denorm_small_shift_dbl0
|
|
add_s r12,r12,1
|
|
brlt r10,0,.Lrsub
|
|
.Ladd_dbl1_gt: ; bit 20 of DBL0H is clear and bit 0 of r12 does not matter
|
|
add.f DBL0L,DBL0L,DBL1L
|
|
add_s DBL0H,DBL0H,DBL1H
|
|
add.cs DBL0H,DBL0H,1
|
|
xor DBL1H,DBL0H,DBL1H
|
|
bbit0 DBL1H,20,.Lno_shiftdown_dbl1_gt
|
|
lsr.f DBL1H,DBL0H
|
|
and r4,DBL0L,2
|
|
bmsk DBL1H,DBL1H,18
|
|
sbc DBL0H,DBL0H,DBL1H
|
|
rrc.f DBL0L,DBL0L
|
|
or.f r12,r12,r4
|
|
cmp.eq r12,r12
|
|
add.cs.f DBL0L,DBL0L,1
|
|
bic.f 0,r9,DBL0H ; check for generating infinity with possible ...
|
|
jne.d [blink] ; ... non-zero fraction
|
|
add.cs DBL0H,DBL0H,1
|
|
mov_s DBL0L,0
|
|
bmsk DBL1H,DBL0H,19
|
|
j_s.d [blink]
|
|
bic_s DBL0H,DBL0H,DBL1H
|
|
.Lno_shiftdown_dbl1_gt:
|
|
add.f 0,r12,r12
|
|
btst.eq DBL0L,0
|
|
cmp.eq r12,r12
|
|
add.cs.f DBL0L,DBL0L,1
|
|
j_s.d [blink]
|
|
add.cs DBL0H,DBL0H,1
|
|
|
|
.balign 4
|
|
.Large_shift_dbl0:
|
|
brhs r8,55,.Lret_dbl1
|
|
bmsk_s DBL0H,DBL0H,19
|
|
brne r6,0,.Lno_denorm_large_shift_dbl0
|
|
add_s r12,r12,1
|
|
brne.d r8,33,.Lfixed_denorm_large_shift_dbl0
|
|
sub r8,r8,1
|
|
bset_s DBL0H,DBL0H,20
|
|
.Lshift32_dbl0:
|
|
mov_s r12,DBL0L
|
|
mov_s DBL0L,DBL0H
|
|
brlt.d r10,0,.Lrsub
|
|
mov_s DBL0H,0
|
|
b_s .Ladd_dbl1_gt
|
|
|
|
.balign 4
|
|
.Lno_denorm_large_shift_dbl0:
|
|
breq.d r8,32,.Lshift32_dbl0
|
|
bset_l DBL0H,DBL0H,20
|
|
.Lfixed_denorm_large_shift_dbl0:
|
|
asl r4,DBL0H,r12
|
|
lsr r5,DBL0L,r8
|
|
asl.f 0,DBL0L,r12
|
|
lsr DBL0L,DBL0H,r8
|
|
or r12,r4,r5
|
|
tst.eq r12,1
|
|
or.ne r12,r12,2
|
|
brlt.d r10,0,.Lrsub
|
|
mov_s DBL0H,0
|
|
b_l .Ladd_dbl1_gt
|
|
ENDFUNC(__adddf3)
|
|
ENDFUNC(__subdf3)
|