[Qemu-devel] [PATCH 5/6] target/s390x: fix PACK reading 1 byte less and writing 1 byte more

[Pavel Zbitskiy]

PACK fails on the test from the Principles of Operation: F1F2F3F4
becomes 0000234C instead of 0001234C due to an off-by-one error.
Furthermore, it overwrites one extra byte to the left of F1.

Signed-off-by: Pavel Zbitskiy <address@hidden>
---
 target/s390x/mem_helper.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/target/s390x/mem_helper.c b/target/s390x/mem_helper.c
index 704d0193b5..bacae4f503 100644
--- a/target/s390x/mem_helper.c
+++ b/target/s390x/mem_helper.c
@@ -1019,15 +1019,15 @@ void HELPER(pack)(CPUS390XState *env, uint32_t len, 
uint64_t dest, uint64_t src)
     len_src--;
 
     /* now pack every value */
-    while (len_dest >= 0) {
+    while (len_dest > 0) {
         b = 0;
 
-        if (len_src > 0) {
+        if (len_src >= 0) {
             b = cpu_ldub_data_ra(env, src, ra) & 0x0f;
             src--;
             len_src--;
         }
-        if (len_src > 0) {
+        if (len_src >= 0) {
             b |= cpu_ldub_data_ra(env, src, ra) << 4;
             src--;
             len_src--;
-- 
2.16.2.windows.1