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go/src/runtime/memmove_wasm.s

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runtime: add js/wasm architecture This commit adds the js/wasm architecture to the runtime package. Currently WebAssembly has no support for threads yet, see https://github.com/WebAssembly/design/issues/1073. Because of that, there is no preemption of goroutines and no sysmon goroutine. Design doc: https://docs.google.com/document/d/131vjr4DH6JFnb-blm_uRdaC0_Nv3OUwjEY5qVCxCup4 About WebAssembly assembly files: https://docs.google.com/document/d/1GRmy3rA4DiYtBlX-I1Jr_iHykbX8EixC3Mq0TCYqbKc Updates #18892 Change-Id: I7f12d21b5180500d55ae9fd2f7e926a1731db391 Reviewed-on: https://go-review.googlesource.com/103877 Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Austin Clements <austin@google.com>
2018-03-31 15:14:17 -06:00
// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "textflag.h"
runtime: document special memmove requirements Unlike C's memmove, Go's memmove must be careful to do indivisible writes of pointer values because it may be racing with the garbage collector reading the heap. We've had various bugs related to this over the years (#36101, #13160, #12552). Indeed, memmove is a great target for optimization and it's easy to forget the special requirements of Go's memmove. The CL documents these (currently unwritten!) requirements. We're also adding a test that should hopefully keep everyone honest going forward, though it's hard to be sure we're hitting all cases of memmove. Change-Id: I2f59f8d8d6fb42d2f10006b55d605b5efd8ddc24 Reviewed-on: https://go-review.googlesource.com/c/go/+/213418 Reviewed-by: Cherry Zhang <cherryyz@google.com>
2020-01-06 09:10:26 -07:00
// See memmove Go doc for important implementation constraints.
runtime: use Go function signatures for memclr and memmove comments The function signatures in the comments used a C-like style. Using Go function signatures is cleaner. Change-Id: I1a093ed8fe5df59f3697c613cf3fce58bba4f5c1 Reviewed-on: https://go-review.googlesource.com/113876 Run-TryBot: Michael Munday <mike.munday@ibm.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
2018-05-21 04:22:00 -06:00
// func memmove(to, from unsafe.Pointer, n uintptr)
runtime: add js/wasm architecture This commit adds the js/wasm architecture to the runtime package. Currently WebAssembly has no support for threads yet, see https://github.com/WebAssembly/design/issues/1073. Because of that, there is no preemption of goroutines and no sysmon goroutine. Design doc: https://docs.google.com/document/d/131vjr4DH6JFnb-blm_uRdaC0_Nv3OUwjEY5qVCxCup4 About WebAssembly assembly files: https://docs.google.com/document/d/1GRmy3rA4DiYtBlX-I1Jr_iHykbX8EixC3Mq0TCYqbKc Updates #18892 Change-Id: I7f12d21b5180500d55ae9fd2f7e926a1731db391 Reviewed-on: https://go-review.googlesource.com/103877 Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Austin Clements <austin@google.com>
2018-03-31 15:14:17 -06:00
TEXT runtime·memmove(SB), NOSPLIT, $0-24
MOVD to+0(FP), R0
MOVD from+8(FP), R1
MOVD n+16(FP), R2
Get R0
Get R1
I64LtU
If // forward
exit_forward_64:
Block
loop_forward_64:
Loop
Get R2
I64Const $8
I64LtU
BrIf exit_forward_64
MOVD 0(R1), 0(R0)
Get R0
I64Const $8
I64Add
Set R0
Get R1
I64Const $8
I64Add
Set R1
Get R2
I64Const $8
I64Sub
Set R2
Br loop_forward_64
End
End
loop_forward_8:
Loop
Get R2
I64Eqz
If
RET
End
Get R0
I32WrapI64
I64Load8U (R1)
I64Store8 $0
Get R0
I64Const $1
I64Add
Set R0
Get R1
I64Const $1
I64Add
Set R1
Get R2
I64Const $1
I64Sub
Set R2
Br loop_forward_8
End
Else
// backward
Get R0
Get R2
I64Add
Set R0
Get R1
Get R2
I64Add
Set R1
exit_backward_64:
Block
loop_backward_64:
Loop
Get R2
I64Const $8
I64LtU
BrIf exit_backward_64
Get R0
I64Const $8
I64Sub
Set R0
Get R1
I64Const $8
I64Sub
Set R1
Get R2
I64Const $8
I64Sub
Set R2
MOVD 0(R1), 0(R0)
Br loop_backward_64
End
End
loop_backward_8:
Loop
Get R2
I64Eqz
If
RET
End
Get R0
I64Const $1
I64Sub
Set R0
Get R1
I64Const $1
I64Sub
Set R1
Get R2
I64Const $1
I64Sub
Set R2
Get R0
I32WrapI64
I64Load8U (R1)
I64Store8 $0
Br loop_backward_8
End
End
UNDEF
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