runtime: Stop arm memmove corrupting its parameters

Change use of x+(SP) to access the stack frame into x-(SP)

Fixes #5925.

R=golang-dev, bradfitz, dave, remyoudompheng, nick, rsc
CC=dave cheney <dave, golang-dev
https://golang.org/cl/11647043

diff --git a/src/pkg/runtime/memmove_arm.s b/src/pkg/runtime/memmove_arm.s
index 562fc0fad19686defaaec01568cce348f851e947..ce8f9fd4d5c8665b8bce6dfda77bbd9fa01a61a9 100644 (file)
--- a/src/pkg/runtime/memmove_arm.s
+++ b/src/pkg/runtime/memmove_arm.s
@@ -85,7 +85,7 @@ _b4aligned:                           /* is source now aligned? */
        BNE     _bunaligned
 
        ADD     $31, R(TS), R(TMP)      /* do 32-byte chunks if possible */
-       MOVW    R(TS), savedts+4(SP)
+       MOVW    R(TS), savedts-4(SP)
 _b32loop:
        CMP     R(TMP), R(TE)
        BLS     _b4tail
@@ -95,7 +95,7 @@ _b32loop:
        B       _b32loop
 
 _b4tail:                               /* do remaining words if possible */
-       MOVW    savedts+4(SP), R(TS)
+       MOVW    savedts-4(SP), R(TS)
        ADD     $3, R(TS), R(TMP)
 _b4loop:
        CMP     R(TMP), R(TE)
@@ -130,7 +130,7 @@ _f4aligned:                         /* is source now aligned? */
        BNE     _funaligned
 
        SUB     $31, R(TE), R(TMP)      /* do 32-byte chunks if possible */
-       MOVW    R(TE), savedte+4(SP)
+       MOVW    R(TE), savedte-4(SP)
 _f32loop:
        CMP     R(TMP), R(TS)
        BHS     _f4tail
@@ -140,7 +140,7 @@ _f32loop:
        B       _f32loop
 
 _f4tail:
-       MOVW    savedte+4(SP), R(TE)
+       MOVW    savedte-4(SP), R(TE)
        SUB     $3, R(TE), R(TMP)       /* do remaining words if possible */
 _f4loop:
        CMP     R(TMP), R(TS)
@@ -182,7 +182,7 @@ _bunaligned:
        BLS     _b1tail
 
        BIC     $3, R(FROM)             /* align source */
-       MOVW    R(TS), savedts+4(SP)
+       MOVW    R(TS), savedts-4(SP)
        MOVW    (R(FROM)), R(BR0)       /* prime first block register */
 
 _bu16loop:
@@ -206,7 +206,7 @@ _bu16loop:
        B       _bu16loop
 
 _bu1tail:
-       MOVW    savedts+4(SP), R(TS)
+       MOVW    savedts-4(SP), R(TS)
        ADD     R(OFFSET), R(FROM)
        B       _b1tail
 
@@ -230,7 +230,7 @@ _funaligned:
        BHS     _f1tail
 
        BIC     $3, R(FROM)             /* align source */
-       MOVW    R(TE), savedte+4(SP)
+       MOVW    R(TE), savedte-4(SP)
        MOVW.P  4(R(FROM)), R(FR3)      /* prime last block register, implicit write back */
 
 _fu16loop:
@@ -254,6 +254,6 @@ _fu16loop:
        B       _fu16loop
 
 _fu1tail:
-       MOVW    savedte+4(SP), R(TE)
+       MOVW    savedte-4(SP), R(TE)
        SUB     R(OFFSET), R(FROM)
        B       _f1tail