[dev.power64] runtime: manually written parts for linux/power64 and linux/power64le, checkpoint
LGTM=rsc
R=rsc, iant
CC=golang-codereviews
https://golang.org/cl/122430043
diff --git a/src/pkg/runtime/memmove_power64x.s b/src/pkg/runtime/memmove_power64x.s
new file mode 100644
index 0000000..b618f0a
--- /dev/null
+++ b/src/pkg/runtime/memmove_power64x.s
@@ -0,0 +1,40 @@
+// Copyright 2014 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.
+
+// +build power64 power64le
+
+#include "../../cmd/ld/textflag.h"
+
+// void runtime·memmove(void*, void*, uintptr)
+TEXT runtime·memmove(SB), NOSPLIT, $-8-24
+ MOVD to+0(FP), R3
+ MOVD from+8(FP), R4
+ MOVD n+16(FP), R5
+ CMP R5, $0
+ BNE check
+ RETURN
+
+check:
+ CMP R3, R4
+ BGT backward
+
+ SUB $1, R3
+ ADD R3, R5
+ SUB $1, R4
+loop:
+ MOVBU 1(R4), R6
+ MOVBU R6, 1(R3)
+ CMP R3, R5
+ BNE loop
+ RETURN
+
+backward:
+ ADD R5, R4
+ ADD R3, R5
+loop1:
+ MOVBU -1(R4), R6
+ MOVBU R6, -1(R5)
+ CMP R3, R5
+ BNE loop1
+ RETURN
