bugs in memmove:

	- has arguments (no stack split)
	- MOVL does not set condition

R=ken2, rsc
https://golang.org/cl/156086

src/pkg/runtime/386/memmove.s

@@ -23,11 +23,12 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 // THE SOFTWARE.
 
-	TEXT	memmove(SB), $0
+	TEXT	memmove(SB), 7, $0
 
 	MOVL	to+0(FP), DI
 	MOVL	fr+4(FP), SI
 	MOVL	n+8(FP), BX
+	CMPL	BX, $0
 	JLT	fault
 
 /*
@@ -38,7 +39,7 @@
 	JLS	back
 
 /*
- * foreward copy loop
+ * forward copy loop
  */
 	MOVL	BX, CX
 	SHRL	$2, CX

src/pkg/runtime/amd64/memmove.s

@@ -23,11 +23,12 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 // THE SOFTWARE.
 
-	TEXT	memmove(SB), $0
+	TEXT	memmove(SB), 7, $0
 
 	MOVQ	to+0(FP), DI
 	MOVQ	fr+8(FP), SI
 	MOVLQSX	n+16(FP), BX
+	CMPQ	BX, $0
 	JLT	fault
 
 /*
@@ -38,7 +39,7 @@
 	JLS	back
 
 /*
- * foreward copy loop
+ * forward copy loop
  */
 	MOVQ	BX, CX
 	SHRQ	$3, CX

src/pkg/runtime/arm/memmove.s

@@ -30,8 +30,7 @@ N = 3
 TMP = 3					/* N and TMP don't overlap */
 TMP1 = 4
 
-TEXT	memcpy(SB), $0
-TEXT memmove(SB), $-4
+TEXT memmove(SB), 7, $-4
 _memmove:
 	MOVW	R(TS), to+0(FP)		/* need to save for return value */
 	MOVW	from+4(FP), R(FROM)