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70138a2108
The uint64 divide function calls _mul64x32 to do a 64x32-bit multiply and then compares the result against the 64-bit numerator. If the result is bigger than the numerator, must use the slow path. Unfortunately, the 64x32 produces a 96-bit product, and only the low 64 bits were being used in the comparison. Return all 96 bits, the bottom 64 via the original uint64* pointer, and the top 32 as the function's return value. Fixes 386 build (broken by ARM division tests). R=golang-dev, iant CC=golang-dev https://golang.org/cl/13722044
55 lines
1.9 KiB
ArmAsm
55 lines
1.9 KiB
ArmAsm
// Inferno's libkern/vlop-386.s
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// http://code.google.com/p/inferno-os/source/browse/libkern/vlop-386.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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#include "../../cmd/ld/textflag.h"
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/*
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* C runtime for 64-bit divide.
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*/
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// _mul64x32(r *uint64, a uint64, b uint32)
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// sets *r = low 64 bits of 96-bit product a*b; returns high 32 bits.
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TEXT _mul64by32(SB), NOSPLIT, $0
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MOVL r+0(FP), CX
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MOVL a+4(FP), AX
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MULL b+12(FP)
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MOVL AX, 0(CX)
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MOVL DX, BX
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MOVL a+8(FP), AX
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MULL b+12(FP)
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ADDL AX, BX
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ADCL $0, DX
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MOVL BX, 4(CX)
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MOVL DX, AX
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RET
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TEXT _div64by32(SB), NOSPLIT, $0
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MOVL r+12(FP), CX
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MOVL a+0(FP), AX
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MOVL a+4(FP), DX
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DIVL b+8(FP)
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MOVL DX, 0(CX)
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RET
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