target-arm: Fix GE bits for v6media signed modulo arithmetic

Fix the signed modulo arithmetic helpers for the v6media
instructions (SADD8, SSUB8, SADD16, SSUB16, SASX, SSAX) to set
the GE bits correctly (based on the result of the add or subtract
before it is truncated to 16 bits, not after).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

diff --git a/target-arm/helper.c b/target-arm/helper.c
index d36012139784b016e27797708ee0760cf61a611c..4f2b44036f1a0b4e6129788418362fb8fba4c150 100644 (file)
--- a/target-arm/helper.c
+++ b/target-arm/helper.c
@@ -2171,7 +2171,7 @@ static inline uint8_t sub8_usat(uint8_t a, uint8_t b)
 /* Signed modulo arithmetic.  */
 #define SARITH16(a, b, n, op) do { \
     int32_t sum; \
-    sum = (int16_t)((uint16_t)(a) op (uint16_t)(b)); \
+    sum = (int32_t)(int16_t)(a) op (int32_t)(int16_t)(b); \
     RESULT(sum, n, 16); \
     if (sum >= 0) \
         ge |= 3 << (n * 2); \
@@ -2179,7 +2179,7 @@ static inline uint8_t sub8_usat(uint8_t a, uint8_t b)
 
 #define SARITH8(a, b, n, op) do { \
     int32_t sum; \
-    sum = (int8_t)((uint8_t)(a) op (uint8_t)(b)); \
+    sum = (int32_t)(int8_t)(a) op (int32_t)(int8_t)(b); \
     RESULT(sum, n, 8); \
     if (sum >= 0) \
         ge |= 1 << n; \