target/arm: Fix VLDRB/H/W for predicated elements

For vector loads, predicated elements are zeroed, instead of
retaining their previous values (as happens for most data
processing operations). This means we need to distinguish
"beat not executed due to ECI" (don't touch destination
element) from "beat executed but predicated out" (zero
destination element).

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

diff --git a/target/arm/mve_helper.c b/target/arm/mve_helper.c
index bc89ce94d5ac45bfe5fb1173e47aee54ed03599c..be8b95453178a2f52be958dcef64f1946ab313f8 100644 (file)
--- a/target/arm/mve_helper.c
+++ b/target/arm/mve_helper.c
@@ -146,12 +146,13 @@ static void mve_advance_vpt(CPUARMState *env)
     env->v7m.vpr = vpr;
 }
 
-
+/* For loads, predicated lanes are zeroed instead of keeping their old values */
 #define DO_VLDR(OP, MSIZE, LDTYPE, ESIZE, TYPE)                         \
     void HELPER(mve_##OP)(CPUARMState *env, void *vd, uint32_t addr)    \
     {                                                                   \
         TYPE *d = vd;                                                   \
         uint16_t mask = mve_element_mask(env);                          \
+        uint16_t eci_mask = mve_eci_mask(env);                          \
         unsigned b, e;                                                  \
         /*                                                              \
          * R_SXTM allows the dest reg to become UNKNOWN for abandoned   \
@@ -159,8 +160,9 @@ static void mve_advance_vpt(CPUARMState *env)
          * then take an exception.                                      \
          */                                                             \
         for (b = 0, e = 0; b < 16; b += ESIZE, e++) {                   \
-            if (mask & (1 << b)) {                                      \
-                d[H##ESIZE(e)] = cpu_##LDTYPE##_data_ra(env, addr, GETPC()); \
+            if (eci_mask & (1 << b)) {                                  \
+                d[H##ESIZE(e)] = (mask & (1 << b)) ?                    \
+                    cpu_##LDTYPE##_data_ra(env, addr, GETPC()) : 0;     \
             }                                                           \
             addr += MSIZE;                                              \
         }                                                               \