target/arm: Implement MVE integer min/max across vector

Implement the MVE integer min/max across vector insns
VMAXV, VMINV, VMAXAV and VMINAV, which find the maximum
from the vector elements and a general purpose register,
and store the maximum back into the general purpose
register.

These insns overlap with VRMLALDAVH (they use what would
be RdaHi=0b110).

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

4 files changed, 150 insertions, 2 deletions

diff --git a/target/arm/helper-mve.h b/target/arm/helper-mve.h
index 0ee5ea3..2c66fcb 100644
--- a/target/arm/helper-mve.h
+++ b/target/arm/helper-mve.h
@@ -379,6 +379,26 @@ DEF_HELPER_FLAGS_3(mve_vaddvuh, TCG_CALL_NO_WG, i32, env, ptr, i32)
 DEF_HELPER_FLAGS_3(mve_vaddvsw, TCG_CALL_NO_WG, i32, env, ptr, i32)
 DEF_HELPER_FLAGS_3(mve_vaddvuw, TCG_CALL_NO_WG, i32, env, ptr, i32)
 
+DEF_HELPER_FLAGS_3(mve_vmaxvsb, TCG_CALL_NO_WG, i32, env, ptr, i32)
+DEF_HELPER_FLAGS_3(mve_vmaxvsh, TCG_CALL_NO_WG, i32, env, ptr, i32)
+DEF_HELPER_FLAGS_3(mve_vmaxvsw, TCG_CALL_NO_WG, i32, env, ptr, i32)
+DEF_HELPER_FLAGS_3(mve_vmaxvub, TCG_CALL_NO_WG, i32, env, ptr, i32)
+DEF_HELPER_FLAGS_3(mve_vmaxvuh, TCG_CALL_NO_WG, i32, env, ptr, i32)
+DEF_HELPER_FLAGS_3(mve_vmaxvuw, TCG_CALL_NO_WG, i32, env, ptr, i32)
+DEF_HELPER_FLAGS_3(mve_vmaxavb, TCG_CALL_NO_WG, i32, env, ptr, i32)
+DEF_HELPER_FLAGS_3(mve_vmaxavh, TCG_CALL_NO_WG, i32, env, ptr, i32)
+DEF_HELPER_FLAGS_3(mve_vmaxavw, TCG_CALL_NO_WG, i32, env, ptr, i32)
+
+DEF_HELPER_FLAGS_3(mve_vminvsb, TCG_CALL_NO_WG, i32, env, ptr, i32)
+DEF_HELPER_FLAGS_3(mve_vminvsh, TCG_CALL_NO_WG, i32, env, ptr, i32)
+DEF_HELPER_FLAGS_3(mve_vminvsw, TCG_CALL_NO_WG, i32, env, ptr, i32)
+DEF_HELPER_FLAGS_3(mve_vminvub, TCG_CALL_NO_WG, i32, env, ptr, i32)
+DEF_HELPER_FLAGS_3(mve_vminvuh, TCG_CALL_NO_WG, i32, env, ptr, i32)
+DEF_HELPER_FLAGS_3(mve_vminvuw, TCG_CALL_NO_WG, i32, env, ptr, i32)
+DEF_HELPER_FLAGS_3(mve_vminavb, TCG_CALL_NO_WG, i32, env, ptr, i32)
+DEF_HELPER_FLAGS_3(mve_vminavh, TCG_CALL_NO_WG, i32, env, ptr, i32)
+DEF_HELPER_FLAGS_3(mve_vminavw, TCG_CALL_NO_WG, i32, env, ptr, i32)
+
 DEF_HELPER_FLAGS_3(mve_vaddlv_s, TCG_CALL_NO_WG, i64, env, ptr, i64)
 DEF_HELPER_FLAGS_3(mve_vaddlv_u, TCG_CALL_NO_WG, i64, env, ptr, i64)
 
diff --git a/target/arm/mve.decode b/target/arm/mve.decode
index bdcd660..83dc030 100644
--- a/target/arm/mve.decode
+++ b/target/arm/mve.decode
@@ -40,6 +40,7 @@
 &vcmp qm qn size mask
 &vcmp_scalar qn rm size mask
 &shl_scalar qda rm size
+&vmaxv qm rda size
 
 @vldr_vstr ....... . . . . l:1 rn:4 ... ...... imm:7 &vldr_vstr qd=%qd u=0
 # Note that both Rn and Qd are 3 bits only (no D bit)
@@ -97,6 +98,8 @@
 @vcmp_scalar .... .... .. size:2 qn:3 . .... .... .... rm:4 &vcmp_scalar \
              mask=%mask_22_13
 
+@vmaxv .... .... .... size:2 .. rda:4 .... .... .... &vmaxv qm=%qm
+
 # Vector loads and stores
 
 # Widening loads and narrowing stores:
@@ -314,8 +317,19 @@ VMLALDAV_U       1111 1110 1 ... ... . ... . 1110 . 0 . 0 ... 0 @vmlaldav
 
 VMLSLDAV         1110 1110 1 ... ... . ... . 1110 . 0 . 0 ... 1 @vmlaldav
 
-VRMLALDAVH_S     1110 1110 1 ... ... 0 ... . 1111 . 0 . 0 ... 0 @vmlaldav_nosz
-VRMLALDAVH_U     1111 1110 1 ... ... 0 ... . 1111 . 0 . 0 ... 0 @vmlaldav_nosz
+{
+  VMAXV_S        1110 1110 1110  .. 10 ....  1111 0 0 . 0 ... 0 @vmaxv
+  VMINV_S        1110 1110 1110  .. 10 ....  1111 1 0 . 0 ... 0 @vmaxv
+  VMAXAV         1110 1110 1110  .. 00 ....  1111 0 0 . 0 ... 0 @vmaxv
+  VMINAV         1110 1110 1110  .. 00 ....  1111 1 0 . 0 ... 0 @vmaxv
+  VRMLALDAVH_S   1110 1110 1 ... ... 0 ... . 1111 . 0 . 0 ... 0 @vmlaldav_nosz
+}
+
+{
+  VMAXV_U        1111 1110 1110  .. 10 ....  1111 0 0 . 0 ... 0 @vmaxv
+  VMINV_U        1111 1110 1110  .. 10 ....  1111 1 0 . 0 ... 0 @vmaxv
+  VRMLALDAVH_U   1111 1110 1 ... ... 0 ... . 1111 . 0 . 0 ... 0 @vmlaldav_nosz
+}
 
 VRMLSLDAVH       1111 1110 1 ... ... 0 ... . 1110 . 0 . 0 ... 1 @vmlaldav_nosz
 
diff --git a/target/arm/mve_helper.c b/target/arm/mve_helper.c
index ac608fc..924ad7f 100644
--- a/target/arm/mve_helper.c
+++ b/target/arm/mve_helper.c
@@ -1254,6 +1254,72 @@ DO_VADDV(vaddvub, 1, uint8_t)
 DO_VADDV(vaddvuh, 2, uint16_t)
 DO_VADDV(vaddvuw, 4, uint32_t)
 
+/*
+ * Vector max/min across vector. Unlike VADDV, we must
+ * read ra as the element size, not its full width.
+ * We work with int64_t internally for simplicity.
+ */
+#define DO_VMAXMINV(OP, ESIZE, TYPE, RATYPE, FN)                \
+    uint32_t HELPER(glue(mve_, OP))(CPUARMState *env, void *vm, \
+                                    uint32_t ra_in)             \
+    {                                                           \
+        uint16_t mask = mve_element_mask(env);                  \
+        unsigned e;                                             \
+        TYPE *m = vm;                                           \
+        int64_t ra = (RATYPE)ra_in;                             \
+        for (e = 0; e < 16 / ESIZE; e++, mask >>= ESIZE) {      \
+            if (mask & 1) {                                     \
+                ra = FN(ra, m[H##ESIZE(e)]);                    \
+            }                                                   \
+        }                                                       \
+        mve_advance_vpt(env);                                   \
+        return ra;                                              \
+    }                                                           \
+
+#define DO_VMAXMINV_U(INSN, FN)                         \
+    DO_VMAXMINV(INSN##b, 1, uint8_t, uint8_t, FN)       \
+    DO_VMAXMINV(INSN##h, 2, uint16_t, uint16_t, FN)     \
+    DO_VMAXMINV(INSN##w, 4, uint32_t, uint32_t, FN)
+#define DO_VMAXMINV_S(INSN, FN)                         \
+    DO_VMAXMINV(INSN##b, 1, int8_t, int8_t, FN)         \
+    DO_VMAXMINV(INSN##h, 2, int16_t, int16_t, FN)       \
+    DO_VMAXMINV(INSN##w, 4, int32_t, int32_t, FN)
+
+/*
+ * Helpers for max and min of absolute values across vector:
+ * note that we only take the absolute value of 'm', not 'n'
+ */
+static int64_t do_maxa(int64_t n, int64_t m)
+{
+    if (m < 0) {
+        m = -m;
+    }
+    return MAX(n, m);
+}
+
+static int64_t do_mina(int64_t n, int64_t m)
+{
+    if (m < 0) {
+        m = -m;
+    }
+    return MIN(n, m);
+}
+
+DO_VMAXMINV_S(vmaxvs, DO_MAX)
+DO_VMAXMINV_U(vmaxvu, DO_MAX)
+DO_VMAXMINV_S(vminvs, DO_MIN)
+DO_VMAXMINV_U(vminvu, DO_MIN)
+/*
+ * VMAXAV, VMINAV treat the general purpose input as unsigned
+ * and the vector elements as signed.
+ */
+DO_VMAXMINV(vmaxavb, 1, int8_t, uint8_t, do_maxa)
+DO_VMAXMINV(vmaxavh, 2, int16_t, uint16_t, do_maxa)
+DO_VMAXMINV(vmaxavw, 4, int32_t, uint32_t, do_maxa)
+DO_VMAXMINV(vminavb, 1, int8_t, uint8_t, do_mina)
+DO_VMAXMINV(vminavh, 2, int16_t, uint16_t, do_mina)
+DO_VMAXMINV(vminavw, 4, int32_t, uint32_t, do_mina)
+
 #define DO_VADDLV(OP, TYPE, LTYPE)                              \
     uint64_t HELPER(glue(mve_, OP))(CPUARMState *env, void *vm, \
                                     uint64_t ra)                \
diff --git a/target/arm/translate-mve.c b/target/arm/translate-mve.c
index 44731fc..2fce74f 100644
--- a/target/arm/translate-mve.c
+++ b/target/arm/translate-mve.c
@@ -1321,3 +1321,51 @@ DO_VCMP(VCMPGE, vcmpge)
 DO_VCMP(VCMPLT, vcmplt)
 DO_VCMP(VCMPGT, vcmpgt)
 DO_VCMP(VCMPLE, vcmple)
+
+static bool do_vmaxv(DisasContext *s, arg_vmaxv *a, MVEGenVADDVFn fn)
+{
+    /*
+     * MIN/MAX operations across a vector: compute the min or
+     * max of the initial value in a general purpose register
+     * and all the elements in the vector, and store it back
+     * into the general purpose register.
+     */
+    TCGv_ptr qm;
+    TCGv_i32 rda;
+
+    if (!dc_isar_feature(aa32_mve, s) || !mve_check_qreg_bank(s, a->qm) ||
+        !fn || a->rda == 13 || a->rda == 15) {
+        /* Rda cases are UNPREDICTABLE */
+        return false;
+    }
+    if (!mve_eci_check(s) || !vfp_access_check(s)) {
+        return true;
+    }
+
+    qm = mve_qreg_ptr(a->qm);
+    rda = load_reg(s, a->rda);
+    fn(rda, cpu_env, qm, rda);
+    store_reg(s, a->rda, rda);
+    tcg_temp_free_ptr(qm);
+    mve_update_eci(s);
+    return true;
+}
+
+#define DO_VMAXV(INSN, FN)                                      \
+    static bool trans_##INSN(DisasContext *s, arg_vmaxv *a)     \
+    {                                                           \
+        static MVEGenVADDVFn * const fns[] = {                  \
+            gen_helper_mve_##FN##b,                             \
+            gen_helper_mve_##FN##h,                             \
+            gen_helper_mve_##FN##w,                             \
+            NULL,                                               \
+        };                                                      \
+        return do_vmaxv(s, a, fns[a->size]);                    \
+    }
+
+DO_VMAXV(VMAXV_S, vmaxvs)
+DO_VMAXV(VMAXV_U, vmaxvu)
+DO_VMAXV(VMAXAV, vmaxav)
+DO_VMAXV(VMINV_S, vminvs)
+DO_VMAXV(VMINV_U, vminvu)
+DO_VMAXV(VMINAV, vminav)