target/arm: Implement MVE integer vector comparisons

Implement the MVE integer vector comparison instructions.  These are
"VCMP (vector)" encodings T1, T2 and T3, and "VPT (vector)" encodings
T1, T2 and T3.

These insns compare corresponding elements in each vector, and update
the VPR.P0 predicate bits with the results of the comparison.  VPT
also sets the VPR.MASK01 and VPR.MASK23 fields -- it is effectively
"VCMP then VPST".

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

1 files changed, 56 insertions, 0 deletions

diff --git a/target/arm/mve_helper.c b/target/arm/mve_helper.c
index 38b4181db2..b0b380b94b 100644
--- a/target/arm/mve_helper.c
+++ b/target/arm/mve_helper.c
@@ -1758,3 +1758,59 @@ static uint32_t do_sub_wrap(uint32_t offset, uint32_t wrap, uint32_t imm)
 DO_VIDUP_ALL(vidup, DO_ADD)
 DO_VIWDUP_ALL(viwdup, do_add_wrap)
 DO_VIWDUP_ALL(vdwdup, do_sub_wrap)
+
+/*
+ * Vector comparison.
+ * P0 bits for non-executed beats (where eci_mask is 0) are unchanged.
+ * P0 bits for predicated lanes in executed beats (where mask is 0) are 0.
+ * P0 bits otherwise are updated with the results of the comparisons.
+ * We must also keep unchanged the MASK fields at the top of v7m.vpr.
+ */
+#define DO_VCMP(OP, ESIZE, TYPE, FN)                                    \
+    void HELPER(glue(mve_, OP))(CPUARMState *env, void *vn, void *vm)   \
+    {                                                                   \
+        TYPE *n = vn, *m = vm;                                          \
+        uint16_t mask = mve_element_mask(env);                          \
+        uint16_t eci_mask = mve_eci_mask(env);                          \
+        uint16_t beatpred = 0;                                          \
+        uint16_t emask = MAKE_64BIT_MASK(0, ESIZE);                     \
+        unsigned e;                                                     \
+        for (e = 0; e < 16 / ESIZE; e++) {                              \
+            bool r = FN(n[H##ESIZE(e)], m[H##ESIZE(e)]);                \
+            /* Comparison sets 0/1 bits for each byte in the element */ \
+            beatpred |= r * emask;                                      \
+            emask <<= ESIZE;                                            \
+        }                                                               \
+        beatpred &= mask;                                               \
+        env->v7m.vpr = (env->v7m.vpr & ~(uint32_t)eci_mask) |           \
+            (beatpred & eci_mask);                                      \
+        mve_advance_vpt(env);                                           \
+    }
+
+#define DO_VCMP_S(OP, FN)                       \
+    DO_VCMP(OP##b, 1, int8_t, FN)               \
+    DO_VCMP(OP##h, 2, int16_t, FN)              \
+    DO_VCMP(OP##w, 4, int32_t, FN)
+
+#define DO_VCMP_U(OP, FN)                       \
+    DO_VCMP(OP##b, 1, uint8_t, FN)              \
+    DO_VCMP(OP##h, 2, uint16_t, FN)             \
+    DO_VCMP(OP##w, 4, uint32_t, FN)
+
+#define DO_EQ(N, M) ((N) == (M))
+#define DO_NE(N, M) ((N) != (M))
+#define DO_EQ(N, M) ((N) == (M))
+#define DO_EQ(N, M) ((N) == (M))
+#define DO_GE(N, M) ((N) >= (M))
+#define DO_LT(N, M) ((N) < (M))
+#define DO_GT(N, M) ((N) > (M))
+#define DO_LE(N, M) ((N) <= (M))
+
+DO_VCMP_U(vcmpeq, DO_EQ)
+DO_VCMP_U(vcmpne, DO_NE)
+DO_VCMP_U(vcmpcs, DO_GE)
+DO_VCMP_U(vcmphi, DO_GT)
+DO_VCMP_S(vcmpge, DO_GE)
+DO_VCMP_S(vcmplt, DO_LT)
+DO_VCMP_S(vcmpgt, DO_GT)
+DO_VCMP_S(vcmple, DO_LE)