2009-06-10 12:53:07 -06:00
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// Inferno's libkern/vlop-arm.s
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// http://code.google.com/p/inferno-os/source/browse/libkern/vlop-arm.s
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//
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// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
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// Revisions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com). All rights reserved.
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// Portions Copyright 2009 The Go Authors. All rights reserved.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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2013-08-01 18:07:01 -06:00
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#include "zasm_GOOS_GOARCH.h"
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2013-08-07 13:20:05 -06:00
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#include "../../cmd/ld/textflag.h"
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2013-08-01 18:07:01 -06:00
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2009-06-10 12:53:07 -06:00
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arg=0
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/* replaced use of R10 by R11 because the former can be the data segment base register */
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2013-08-07 13:20:05 -06:00
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TEXT _mulv(SB), NOSPLIT, $0
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2009-09-18 17:45:41 -06:00
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MOVW 0(FP), R0
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2010-05-03 14:24:39 -06:00
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MOVW 4(FP), R2 /* l0 */
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MOVW 8(FP), R11 /* h0 */
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MOVW 12(FP), R4 /* l1 */
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MOVW 16(FP), R5 /* h1 */
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2012-06-02 14:03:09 -06:00
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MULLU R4, R2, (R7,R6)
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MUL R11, R4, R8
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2009-06-10 12:53:07 -06:00
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ADD R8, R7
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2012-06-02 14:03:09 -06:00
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MUL R2, R5, R8
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2009-06-10 12:53:07 -06:00
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ADD R8, R7
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2010-05-03 14:24:39 -06:00
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MOVW R6, 0(R(arg))
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MOVW R7, 4(R(arg))
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2009-06-10 12:53:07 -06:00
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RET
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2009-12-17 17:08:42 -07:00
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// trampoline for _sfloat2. passes LR as arg0 and
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2010-04-15 03:43:49 -06:00
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// saves registers R0-R13 and CPSR on the stack. R0-R12 and CPSR flags can
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// be changed by _sfloat2.
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2013-08-07 13:20:05 -06:00
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TEXT _sfloat(SB), NOSPLIT, $64-0 // 4 arg + 14*4 saved regs + cpsr
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2009-12-17 17:08:42 -07:00
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MOVW R14, 4(R13)
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MOVW R0, 8(R13)
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MOVW $12(R13), R0
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2010-04-15 03:43:49 -06:00
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MOVM.IA.W [R1-R12], (R0)
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MOVW $68(R13), R1 // correct for frame size
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MOVW R1, 60(R13)
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WORD $0xe10f1000 // mrs r1, cpsr
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MOVW R1, 64(R13)
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2013-08-01 18:07:01 -06:00
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// Disable preemption of this goroutine during _sfloat2 by
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// m->locks++ and m->locks-- around the call.
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// Rescheduling this goroutine may cause the loss of the
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// contents of the software floating point registers in
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// m->freghi, m->freglo, m->fflag, if the goroutine is moved
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// to a different m or another goroutine runs on this m.
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// Rescheduling at ordinary function calls is okay because
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// all registers are caller save, but _sfloat2 and the things
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// that it runs are simulating the execution of individual
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// program instructions, and those instructions do not expect
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// the floating point registers to be lost.
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// An alternative would be to move the software floating point
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// registers into G, but they do not need to be kept at the
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// usual places a goroutine reschedules (at function calls),
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// so it would be a waste of 132 bytes per G.
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MOVW m_locks(m), R1
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ADD $1, R1
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MOVW R1, m_locks(m)
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2014-04-03 13:39:48 -06:00
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MOVW $1, R1
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MOVW R1, m_softfloat(m)
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2010-11-10 16:10:19 -07:00
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BL runtime·_sfloat2(SB)
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2013-08-01 18:07:01 -06:00
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MOVW m_locks(m), R1
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SUB $1, R1
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MOVW R1, m_locks(m)
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2014-04-03 13:39:48 -06:00
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MOVW $0, R1
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MOVW R1, m_softfloat(m)
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2009-12-17 17:08:42 -07:00
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MOVW R0, 0(R13)
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2010-04-15 03:43:49 -06:00
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MOVW 64(R13), R1
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WORD $0xe128f001 // msr cpsr_f, r1
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2009-12-17 17:08:42 -07:00
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MOVW $12(R13), R0
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2013-07-31 22:16:31 -06:00
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// Restore R1-R8 and R11-R12, but ignore the saved R9 (m) and R10 (g).
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// Both are maintained by the runtime and always have correct values,
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// so there is no need to restore old values here.
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// The g should not have changed, but m may have, if we were preempted
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// and restarted on a different thread, in which case restoring the old
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// value is incorrect and will cause serious confusion in the runtime.
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MOVM.IA.W (R0), [R1-R8]
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MOVW $52(R13), R0
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MOVM.IA.W (R0), [R11-R12]
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2009-12-17 17:08:42 -07:00
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MOVW 8(R13), R0
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RET
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2012-10-20 02:40:19 -06:00
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// func udiv(n, d uint32) (q, r uint32)
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// Reference:
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// Sloss, Andrew et. al; ARM System Developer's Guide: Designing and Optimizing System Software
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// Morgan Kaufmann; 1 edition (April 8, 2004), ISBN 978-1558608740
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q = 0 // input d, output q
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r = 1 // input n, output r
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s = 2 // three temporary variables
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2013-05-29 13:03:52 -06:00
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M = 3
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2012-10-20 02:40:19 -06:00
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a = 11
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2013-09-16 12:04:45 -06:00
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// Be careful: R(a) == R11 will be used by the linker for synthesized instructions.
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undo CL 19810043 / 352f3b7c9664
The CL causes misc/cgo/test to fail randomly.
I suspect that the problem is the use of a division instruction
in usleep, which can be called while trying to acquire an m
and therefore cannot store the denominator in m.
The solution to that would be to rewrite the code to use a
magic multiply instead of a divide, but now we're getting
pretty far off the original code.
Go back to the original in preparation for a different,
less efficient but simpler fix.
««« original CL description
cmd/5l, runtime: make ARM integer division profiler-friendly
The implementation of division constructed non-standard
stack frames that could not be handled by the traceback
routines.
CL 13239052 left the frames non-standard but fixed them
for the specific case of a divide-by-zero panic.
A profiling signal can arrive at any time, so that fix
is not sufficient.
Change the division to store the extra argument in the M struct
instead of in a new stack slot. That keeps the frames bog standard
at all times.
Also fix a related bug in the traceback code: when starting
a traceback, the LR register should be ignored if the current
function has already allocated its stack frame and saved the
original LR on the stack. The stack copy should be used, as the
LR register may have been modified.
Combined, these make the torture test from issue 6681 pass.
Fixes #6681.
R=golang-dev, r, josharian
CC=golang-dev
https://golang.org/cl/19810043
»»»
TBR=r
CC=golang-dev
https://golang.org/cl/20350043
2013-10-31 11:18:57 -06:00
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TEXT udiv<>(SB),NOSPLIT,$-4
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2012-10-20 02:40:19 -06:00
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CLZ R(q), R(s) // find normalizing shift
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MOVW.S R(q)<<R(s), R(a)
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2013-09-16 12:04:45 -06:00
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MOVW $fast_udiv_tab<>-64(SB), R(M)
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MOVBU.NE R(a)>>25(R(M)), R(a) // index by most significant 7 bits of divisor
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2012-10-20 02:40:19 -06:00
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SUB.S $7, R(s)
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2013-05-29 13:03:52 -06:00
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RSB $0, R(q), R(M) // M = -q
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2012-10-20 02:40:19 -06:00
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MOVW.PL R(a)<<R(s), R(q)
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// 1st Newton iteration
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2013-05-29 13:03:52 -06:00
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MUL.PL R(M), R(q), R(a) // a = -q*d
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2012-10-20 02:40:19 -06:00
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BMI udiv_by_large_d
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MULAWT R(a), R(q), R(q), R(q) // q approx q-(q*q*d>>32)
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2013-05-29 13:03:52 -06:00
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TEQ R(M)->1, R(M) // check for d=0 or d=1
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2012-10-20 02:40:19 -06:00
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// 2nd Newton iteration
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2013-05-29 13:03:52 -06:00
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MUL.NE R(M), R(q), R(a)
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2012-10-20 02:40:19 -06:00
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MOVW.NE $0, R(s)
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MULAL.NE R(q), R(a), (R(q),R(s))
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BEQ udiv_by_0_or_1
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// q now accurate enough for a remainder r, 0<=r<3*d
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MULLU R(q), R(r), (R(q),R(s)) // q = (r * q) >> 32
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2013-05-29 13:03:52 -06:00
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ADD R(M), R(r), R(r) // r = n - d
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MULA R(M), R(q), R(r), R(r) // r = n - (q+1)*d
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2012-10-20 02:40:19 -06:00
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// since 0 <= n-q*d < 3*d; thus -d <= r < 2*d
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2013-05-29 13:03:52 -06:00
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CMN R(M), R(r) // t = r-d
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SUB.CS R(M), R(r), R(r) // if (t<-d || t>=0) r=r+d
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2012-10-20 02:40:19 -06:00
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ADD.CC $1, R(q)
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2013-05-29 13:03:52 -06:00
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ADD.PL R(M)<<1, R(r)
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2012-10-20 02:40:19 -06:00
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ADD.PL $2, R(q)
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2013-09-16 12:04:45 -06:00
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RET
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2012-10-20 02:40:19 -06:00
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udiv_by_large_d:
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// at this point we know d>=2^(31-6)=2^25
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SUB $4, R(a), R(a)
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RSB $0, R(s), R(s)
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MOVW R(a)>>R(s), R(q)
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MULLU R(q), R(r), (R(q),R(s))
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2013-05-29 13:03:52 -06:00
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MULA R(M), R(q), R(r), R(r)
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2012-10-20 02:40:19 -06:00
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// q now accurate enough for a remainder r, 0<=r<4*d
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2013-05-29 13:03:52 -06:00
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CMN R(r)>>1, R(M) // if(r/2 >= d)
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ADD.CS R(M)<<1, R(r)
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2012-10-20 02:40:19 -06:00
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ADD.CS $2, R(q)
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2013-05-29 13:03:52 -06:00
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CMN R(r), R(M)
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ADD.CS R(M), R(r)
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2012-10-20 02:40:19 -06:00
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ADD.CS $1, R(q)
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2013-09-16 12:04:45 -06:00
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RET
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2012-10-20 02:40:19 -06:00
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udiv_by_0_or_1:
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// carry set if d==1, carry clear if d==0
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2013-09-16 12:04:45 -06:00
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BCC udiv_by_0
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MOVW R(r), R(q)
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MOVW $0, R(r)
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RET
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2012-10-20 02:40:19 -06:00
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2013-09-16 12:04:45 -06:00
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udiv_by_0:
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undo CL 19810043 / 352f3b7c9664
The CL causes misc/cgo/test to fail randomly.
I suspect that the problem is the use of a division instruction
in usleep, which can be called while trying to acquire an m
and therefore cannot store the denominator in m.
The solution to that would be to rewrite the code to use a
magic multiply instead of a divide, but now we're getting
pretty far off the original code.
Go back to the original in preparation for a different,
less efficient but simpler fix.
««« original CL description
cmd/5l, runtime: make ARM integer division profiler-friendly
The implementation of division constructed non-standard
stack frames that could not be handled by the traceback
routines.
CL 13239052 left the frames non-standard but fixed them
for the specific case of a divide-by-zero panic.
A profiling signal can arrive at any time, so that fix
is not sufficient.
Change the division to store the extra argument in the M struct
instead of in a new stack slot. That keeps the frames bog standard
at all times.
Also fix a related bug in the traceback code: when starting
a traceback, the LR register should be ignored if the current
function has already allocated its stack frame and saved the
original LR on the stack. The stack copy should be used, as the
LR register may have been modified.
Combined, these make the torture test from issue 6681 pass.
Fixes #6681.
R=golang-dev, r, josharian
CC=golang-dev
https://golang.org/cl/19810043
»»»
TBR=r
CC=golang-dev
https://golang.org/cl/20350043
2013-10-31 11:18:57 -06:00
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// The ARM toolchain expects it can emit references to DIV and MOD
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// instructions. The linker rewrites each pseudo-instruction into
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// a sequence that pushes two values onto the stack and then calls
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// _divu, _modu, _div, or _mod (below), all of which have a 16-byte
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// frame plus the saved LR. The traceback routine knows the expanded
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// stack frame size at the pseudo-instruction call site, but it
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// doesn't know that the frame has a non-standard layout. In particular,
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// it expects to find a saved LR in the bottom word of the frame.
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// Unwind the stack back to the pseudo-instruction call site, copy the
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// saved LR where the traceback routine will look for it, and make it
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// appear that panicdivide was called from that PC.
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MOVW 0(R13), LR
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ADD $20, R13
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MOVW 8(R13), R1 // actual saved LR
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MOVW R1, 0(R13) // expected here for traceback
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B runtime·panicdivide(SB)
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2013-09-16 12:04:45 -06:00
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TEXT fast_udiv_tab<>(SB),NOSPLIT,$-4
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2012-10-20 02:40:19 -06:00
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// var tab [64]byte
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// tab[0] = 255; for i := 1; i <= 63; i++ { tab[i] = (1<<14)/(64+i) }
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// laid out here as little-endian uint32s
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WORD $0xf4f8fcff
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WORD $0xe6eaedf0
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WORD $0xdadde0e3
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WORD $0xcfd2d4d7
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WORD $0xc5c7cacc
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WORD $0xbcbec0c3
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WORD $0xb4b6b8ba
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WORD $0xacaeb0b2
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WORD $0xa5a7a8aa
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WORD $0x9fa0a2a3
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WORD $0x999a9c9d
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WORD $0x93949697
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WORD $0x8e8f9092
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WORD $0x898a8c8d
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WORD $0x85868788
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WORD $0x81828384
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// The linker will pass numerator in R(TMP), and it also
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// expects the result in R(TMP)
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TMP = 11
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|
|
|
|
undo CL 19810043 / 352f3b7c9664
The CL causes misc/cgo/test to fail randomly.
I suspect that the problem is the use of a division instruction
in usleep, which can be called while trying to acquire an m
and therefore cannot store the denominator in m.
The solution to that would be to rewrite the code to use a
magic multiply instead of a divide, but now we're getting
pretty far off the original code.
Go back to the original in preparation for a different,
less efficient but simpler fix.
««« original CL description
cmd/5l, runtime: make ARM integer division profiler-friendly
The implementation of division constructed non-standard
stack frames that could not be handled by the traceback
routines.
CL 13239052 left the frames non-standard but fixed them
for the specific case of a divide-by-zero panic.
A profiling signal can arrive at any time, so that fix
is not sufficient.
Change the division to store the extra argument in the M struct
instead of in a new stack slot. That keeps the frames bog standard
at all times.
Also fix a related bug in the traceback code: when starting
a traceback, the LR register should be ignored if the current
function has already allocated its stack frame and saved the
original LR on the stack. The stack copy should be used, as the
LR register may have been modified.
Combined, these make the torture test from issue 6681 pass.
Fixes #6681.
R=golang-dev, r, josharian
CC=golang-dev
https://golang.org/cl/19810043
»»»
TBR=r
CC=golang-dev
https://golang.org/cl/20350043
2013-10-31 11:18:57 -06:00
|
|
|
TEXT _divu(SB), NOSPLIT, $16
|
2012-10-20 02:40:19 -06:00
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|
|
MOVW R(q), 4(R13)
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MOVW R(r), 8(R13)
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MOVW R(s), 12(R13)
|
2013-05-29 13:03:52 -06:00
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MOVW R(M), 16(R13)
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2012-10-20 02:40:19 -06:00
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MOVW R(TMP), R(r) /* numerator */
|
undo CL 19810043 / 352f3b7c9664
The CL causes misc/cgo/test to fail randomly.
I suspect that the problem is the use of a division instruction
in usleep, which can be called while trying to acquire an m
and therefore cannot store the denominator in m.
The solution to that would be to rewrite the code to use a
magic multiply instead of a divide, but now we're getting
pretty far off the original code.
Go back to the original in preparation for a different,
less efficient but simpler fix.
««« original CL description
cmd/5l, runtime: make ARM integer division profiler-friendly
The implementation of division constructed non-standard
stack frames that could not be handled by the traceback
routines.
CL 13239052 left the frames non-standard but fixed them
for the specific case of a divide-by-zero panic.
A profiling signal can arrive at any time, so that fix
is not sufficient.
Change the division to store the extra argument in the M struct
instead of in a new stack slot. That keeps the frames bog standard
at all times.
Also fix a related bug in the traceback code: when starting
a traceback, the LR register should be ignored if the current
function has already allocated its stack frame and saved the
original LR on the stack. The stack copy should be used, as the
LR register may have been modified.
Combined, these make the torture test from issue 6681 pass.
Fixes #6681.
R=golang-dev, r, josharian
CC=golang-dev
https://golang.org/cl/19810043
»»»
TBR=r
CC=golang-dev
https://golang.org/cl/20350043
2013-10-31 11:18:57 -06:00
|
|
|
MOVW 0(FP), R(q) /* denominator */
|
2012-10-20 02:40:19 -06:00
|
|
|
BL udiv<>(SB)
|
|
|
|
MOVW R(q), R(TMP)
|
|
|
|
MOVW 4(R13), R(q)
|
|
|
|
MOVW 8(R13), R(r)
|
|
|
|
MOVW 12(R13), R(s)
|
2013-05-29 13:03:52 -06:00
|
|
|
MOVW 16(R13), R(M)
|
2012-10-20 02:40:19 -06:00
|
|
|
RET
|
|
|
|
|
undo CL 19810043 / 352f3b7c9664
The CL causes misc/cgo/test to fail randomly.
I suspect that the problem is the use of a division instruction
in usleep, which can be called while trying to acquire an m
and therefore cannot store the denominator in m.
The solution to that would be to rewrite the code to use a
magic multiply instead of a divide, but now we're getting
pretty far off the original code.
Go back to the original in preparation for a different,
less efficient but simpler fix.
««« original CL description
cmd/5l, runtime: make ARM integer division profiler-friendly
The implementation of division constructed non-standard
stack frames that could not be handled by the traceback
routines.
CL 13239052 left the frames non-standard but fixed them
for the specific case of a divide-by-zero panic.
A profiling signal can arrive at any time, so that fix
is not sufficient.
Change the division to store the extra argument in the M struct
instead of in a new stack slot. That keeps the frames bog standard
at all times.
Also fix a related bug in the traceback code: when starting
a traceback, the LR register should be ignored if the current
function has already allocated its stack frame and saved the
original LR on the stack. The stack copy should be used, as the
LR register may have been modified.
Combined, these make the torture test from issue 6681 pass.
Fixes #6681.
R=golang-dev, r, josharian
CC=golang-dev
https://golang.org/cl/19810043
»»»
TBR=r
CC=golang-dev
https://golang.org/cl/20350043
2013-10-31 11:18:57 -06:00
|
|
|
TEXT _modu(SB), NOSPLIT, $16
|
2012-10-20 02:40:19 -06:00
|
|
|
MOVW R(q), 4(R13)
|
|
|
|
MOVW R(r), 8(R13)
|
|
|
|
MOVW R(s), 12(R13)
|
2013-05-29 13:03:52 -06:00
|
|
|
MOVW R(M), 16(R13)
|
2012-10-20 02:40:19 -06:00
|
|
|
|
|
|
|
MOVW R(TMP), R(r) /* numerator */
|
undo CL 19810043 / 352f3b7c9664
The CL causes misc/cgo/test to fail randomly.
I suspect that the problem is the use of a division instruction
in usleep, which can be called while trying to acquire an m
and therefore cannot store the denominator in m.
The solution to that would be to rewrite the code to use a
magic multiply instead of a divide, but now we're getting
pretty far off the original code.
Go back to the original in preparation for a different,
less efficient but simpler fix.
««« original CL description
cmd/5l, runtime: make ARM integer division profiler-friendly
The implementation of division constructed non-standard
stack frames that could not be handled by the traceback
routines.
CL 13239052 left the frames non-standard but fixed them
for the specific case of a divide-by-zero panic.
A profiling signal can arrive at any time, so that fix
is not sufficient.
Change the division to store the extra argument in the M struct
instead of in a new stack slot. That keeps the frames bog standard
at all times.
Also fix a related bug in the traceback code: when starting
a traceback, the LR register should be ignored if the current
function has already allocated its stack frame and saved the
original LR on the stack. The stack copy should be used, as the
LR register may have been modified.
Combined, these make the torture test from issue 6681 pass.
Fixes #6681.
R=golang-dev, r, josharian
CC=golang-dev
https://golang.org/cl/19810043
»»»
TBR=r
CC=golang-dev
https://golang.org/cl/20350043
2013-10-31 11:18:57 -06:00
|
|
|
MOVW 0(FP), R(q) /* denominator */
|
2012-10-20 02:40:19 -06:00
|
|
|
BL udiv<>(SB)
|
|
|
|
MOVW R(r), R(TMP)
|
|
|
|
MOVW 4(R13), R(q)
|
|
|
|
MOVW 8(R13), R(r)
|
|
|
|
MOVW 12(R13), R(s)
|
2013-05-29 13:03:52 -06:00
|
|
|
MOVW 16(R13), R(M)
|
2012-10-20 02:40:19 -06:00
|
|
|
RET
|
|
|
|
|
undo CL 19810043 / 352f3b7c9664
The CL causes misc/cgo/test to fail randomly.
I suspect that the problem is the use of a division instruction
in usleep, which can be called while trying to acquire an m
and therefore cannot store the denominator in m.
The solution to that would be to rewrite the code to use a
magic multiply instead of a divide, but now we're getting
pretty far off the original code.
Go back to the original in preparation for a different,
less efficient but simpler fix.
««« original CL description
cmd/5l, runtime: make ARM integer division profiler-friendly
The implementation of division constructed non-standard
stack frames that could not be handled by the traceback
routines.
CL 13239052 left the frames non-standard but fixed them
for the specific case of a divide-by-zero panic.
A profiling signal can arrive at any time, so that fix
is not sufficient.
Change the division to store the extra argument in the M struct
instead of in a new stack slot. That keeps the frames bog standard
at all times.
Also fix a related bug in the traceback code: when starting
a traceback, the LR register should be ignored if the current
function has already allocated its stack frame and saved the
original LR on the stack. The stack copy should be used, as the
LR register may have been modified.
Combined, these make the torture test from issue 6681 pass.
Fixes #6681.
R=golang-dev, r, josharian
CC=golang-dev
https://golang.org/cl/19810043
»»»
TBR=r
CC=golang-dev
https://golang.org/cl/20350043
2013-10-31 11:18:57 -06:00
|
|
|
TEXT _div(SB),NOSPLIT,$16
|
2012-10-20 02:40:19 -06:00
|
|
|
MOVW R(q), 4(R13)
|
|
|
|
MOVW R(r), 8(R13)
|
|
|
|
MOVW R(s), 12(R13)
|
2013-05-29 13:03:52 -06:00
|
|
|
MOVW R(M), 16(R13)
|
2012-10-20 02:40:19 -06:00
|
|
|
MOVW R(TMP), R(r) /* numerator */
|
undo CL 19810043 / 352f3b7c9664
The CL causes misc/cgo/test to fail randomly.
I suspect that the problem is the use of a division instruction
in usleep, which can be called while trying to acquire an m
and therefore cannot store the denominator in m.
The solution to that would be to rewrite the code to use a
magic multiply instead of a divide, but now we're getting
pretty far off the original code.
Go back to the original in preparation for a different,
less efficient but simpler fix.
««« original CL description
cmd/5l, runtime: make ARM integer division profiler-friendly
The implementation of division constructed non-standard
stack frames that could not be handled by the traceback
routines.
CL 13239052 left the frames non-standard but fixed them
for the specific case of a divide-by-zero panic.
A profiling signal can arrive at any time, so that fix
is not sufficient.
Change the division to store the extra argument in the M struct
instead of in a new stack slot. That keeps the frames bog standard
at all times.
Also fix a related bug in the traceback code: when starting
a traceback, the LR register should be ignored if the current
function has already allocated its stack frame and saved the
original LR on the stack. The stack copy should be used, as the
LR register may have been modified.
Combined, these make the torture test from issue 6681 pass.
Fixes #6681.
R=golang-dev, r, josharian
CC=golang-dev
https://golang.org/cl/19810043
»»»
TBR=r
CC=golang-dev
https://golang.org/cl/20350043
2013-10-31 11:18:57 -06:00
|
|
|
MOVW 0(FP), R(q) /* denominator */
|
2012-10-20 02:40:19 -06:00
|
|
|
CMP $0, R(r)
|
|
|
|
BGE d1
|
|
|
|
RSB $0, R(r), R(r)
|
|
|
|
CMP $0, R(q)
|
|
|
|
BGE d2
|
|
|
|
RSB $0, R(q), R(q)
|
|
|
|
d0:
|
|
|
|
BL udiv<>(SB) /* none/both neg */
|
|
|
|
MOVW R(q), R(TMP)
|
2013-12-08 20:52:08 -07:00
|
|
|
B out1
|
2012-10-20 02:40:19 -06:00
|
|
|
d1:
|
|
|
|
CMP $0, R(q)
|
|
|
|
BGE d0
|
|
|
|
RSB $0, R(q), R(q)
|
|
|
|
d2:
|
|
|
|
BL udiv<>(SB) /* one neg */
|
|
|
|
RSB $0, R(q), R(TMP)
|
2013-12-08 20:52:08 -07:00
|
|
|
out1:
|
|
|
|
MOVW 4(R13), R(q)
|
|
|
|
MOVW 8(R13), R(r)
|
|
|
|
MOVW 12(R13), R(s)
|
|
|
|
MOVW 16(R13), R(M)
|
|
|
|
RET
|
2012-10-20 02:40:19 -06:00
|
|
|
|
undo CL 19810043 / 352f3b7c9664
The CL causes misc/cgo/test to fail randomly.
I suspect that the problem is the use of a division instruction
in usleep, which can be called while trying to acquire an m
and therefore cannot store the denominator in m.
The solution to that would be to rewrite the code to use a
magic multiply instead of a divide, but now we're getting
pretty far off the original code.
Go back to the original in preparation for a different,
less efficient but simpler fix.
««« original CL description
cmd/5l, runtime: make ARM integer division profiler-friendly
The implementation of division constructed non-standard
stack frames that could not be handled by the traceback
routines.
CL 13239052 left the frames non-standard but fixed them
for the specific case of a divide-by-zero panic.
A profiling signal can arrive at any time, so that fix
is not sufficient.
Change the division to store the extra argument in the M struct
instead of in a new stack slot. That keeps the frames bog standard
at all times.
Also fix a related bug in the traceback code: when starting
a traceback, the LR register should be ignored if the current
function has already allocated its stack frame and saved the
original LR on the stack. The stack copy should be used, as the
LR register may have been modified.
Combined, these make the torture test from issue 6681 pass.
Fixes #6681.
R=golang-dev, r, josharian
CC=golang-dev
https://golang.org/cl/19810043
»»»
TBR=r
CC=golang-dev
https://golang.org/cl/20350043
2013-10-31 11:18:57 -06:00
|
|
|
TEXT _mod(SB),NOSPLIT,$16
|
2012-10-20 02:40:19 -06:00
|
|
|
MOVW R(q), 4(R13)
|
|
|
|
MOVW R(r), 8(R13)
|
|
|
|
MOVW R(s), 12(R13)
|
2013-05-29 13:03:52 -06:00
|
|
|
MOVW R(M), 16(R13)
|
2012-10-20 02:40:19 -06:00
|
|
|
MOVW R(TMP), R(r) /* numerator */
|
undo CL 19810043 / 352f3b7c9664
The CL causes misc/cgo/test to fail randomly.
I suspect that the problem is the use of a division instruction
in usleep, which can be called while trying to acquire an m
and therefore cannot store the denominator in m.
The solution to that would be to rewrite the code to use a
magic multiply instead of a divide, but now we're getting
pretty far off the original code.
Go back to the original in preparation for a different,
less efficient but simpler fix.
««« original CL description
cmd/5l, runtime: make ARM integer division profiler-friendly
The implementation of division constructed non-standard
stack frames that could not be handled by the traceback
routines.
CL 13239052 left the frames non-standard but fixed them
for the specific case of a divide-by-zero panic.
A profiling signal can arrive at any time, so that fix
is not sufficient.
Change the division to store the extra argument in the M struct
instead of in a new stack slot. That keeps the frames bog standard
at all times.
Also fix a related bug in the traceback code: when starting
a traceback, the LR register should be ignored if the current
function has already allocated its stack frame and saved the
original LR on the stack. The stack copy should be used, as the
LR register may have been modified.
Combined, these make the torture test from issue 6681 pass.
Fixes #6681.
R=golang-dev, r, josharian
CC=golang-dev
https://golang.org/cl/19810043
»»»
TBR=r
CC=golang-dev
https://golang.org/cl/20350043
2013-10-31 11:18:57 -06:00
|
|
|
MOVW 0(FP), R(q) /* denominator */
|
2012-10-20 02:40:19 -06:00
|
|
|
CMP $0, R(q)
|
|
|
|
RSB.LT $0, R(q), R(q)
|
|
|
|
CMP $0, R(r)
|
|
|
|
BGE m1
|
|
|
|
RSB $0, R(r), R(r)
|
|
|
|
BL udiv<>(SB) /* neg numerator */
|
|
|
|
RSB $0, R(r), R(TMP)
|
|
|
|
B out
|
|
|
|
m1:
|
|
|
|
BL udiv<>(SB) /* pos numerator */
|
|
|
|
MOVW R(r), R(TMP)
|
|
|
|
out:
|
|
|
|
MOVW 4(R13), R(q)
|
|
|
|
MOVW 8(R13), R(r)
|
|
|
|
MOVW 12(R13), R(s)
|
2013-05-29 13:03:52 -06:00
|
|
|
MOVW 16(R13), R(M)
|
2012-10-20 02:40:19 -06:00
|
|
|
RET
|