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Diffstat (limited to 'src/pkg/runtime/amd64/memmove.s')
| -rw-r--r-- | src/pkg/runtime/amd64/memmove.s | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/src/pkg/runtime/amd64/memmove.s b/src/pkg/runtime/amd64/memmove.s new file mode 100644 index 000000000..e78be8145 --- /dev/null +++ b/src/pkg/runtime/amd64/memmove.s @@ -0,0 +1,88 @@ +// Derived from Inferno's libkern/memmove-386.s (adapted for amd64) +// http://code.google.com/p/inferno-os/source/browse/libkern/memmove-386.s +// +// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved. +// Revisions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com). All rights reserved. +// Portions Copyright 2009 The Go Authors. All rights reserved. +// +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: +// +// The above copyright notice and this permission notice shall be included in +// all copies or substantial portions of the Software. +// +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +// THE SOFTWARE. + +TEXT runtime·memmove(SB), 7, $0 + + MOVQ to+0(FP), DI + MOVQ fr+8(FP), SI + MOVLQSX n+16(FP), BX + +/* + * check and set for backwards + */ + CMPQ SI, DI + JLS back + +/* + * forward copy loop + */ +forward: + MOVQ BX, CX + SHRQ $3, CX + ANDQ $7, BX + + REP; MOVSQ + MOVQ BX, CX + REP; MOVSB + + MOVQ to+0(FP),AX + RET +back: +/* + * check overlap + */ + MOVQ SI, CX + ADDQ BX, CX + CMPQ CX, DI + JLS forward + +/* + * whole thing backwards has + * adjusted addresses + */ + ADDQ BX, DI + ADDQ BX, SI + STD + +/* + * copy + */ + MOVQ BX, CX + SHRQ $3, CX + ANDQ $7, BX + + SUBQ $8, DI + SUBQ $8, SI + REP; MOVSQ + + ADDQ $7, DI + ADDQ $7, SI + MOVQ BX, CX + REP; MOVSB + + CLD + MOVQ to+0(FP),AX + RET + |