target/arm: Implement SVE2 saturating multiply-add high

SVE2 has two additional sizes of the operation and unlike NEON,
there is no saturation flag.  Create new entry points for SVE2
that do not set QC.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210525010358.152808-36-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

target/arm/helper.h

@@ -591,6 +591,23 @@ DEF_HELPER_FLAGS_5(gvec_qrdmlah_s32, TCG_CALL_NO_RWG,
 DEF_HELPER_FLAGS_5(gvec_qrdmlsh_s32, TCG_CALL_NO_RWG,
                    void, ptr, ptr, ptr, ptr, i32)
 
+DEF_HELPER_FLAGS_5(sve2_sqrdmlah_b, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, i32)
+DEF_HELPER_FLAGS_5(sve2_sqrdmlsh_b, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, i32)
+DEF_HELPER_FLAGS_5(sve2_sqrdmlah_h, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, i32)
+DEF_HELPER_FLAGS_5(sve2_sqrdmlsh_h, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, i32)
+DEF_HELPER_FLAGS_5(sve2_sqrdmlah_s, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, i32)
+DEF_HELPER_FLAGS_5(sve2_sqrdmlsh_s, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, i32)
+DEF_HELPER_FLAGS_5(sve2_sqrdmlah_d, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, i32)
+DEF_HELPER_FLAGS_5(sve2_sqrdmlsh_d, TCG_CALL_NO_RWG,
+                   void, ptr, ptr, ptr, ptr, i32)
+
 DEF_HELPER_FLAGS_4(gvec_sdot_b, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
 DEF_HELPER_FLAGS_4(gvec_udot_b, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)
 DEF_HELPER_FLAGS_4(gvec_sdot_h, TCG_CALL_NO_RWG, void, ptr, ptr, ptr, i32)

target/arm/sve.decode

@@ -1346,3 +1346,8 @@ SQDMLSLT_zzzw   01000100 .. 0 ..... 0110 11 ..... .....  @rda_rn_rm
 
 SQDMLALBT       01000100 .. 0 ..... 00001 0 ..... .....  @rda_rn_rm
 SQDMLSLBT       01000100 .. 0 ..... 00001 1 ..... .....  @rda_rn_rm
+
+## SVE2 saturating multiply-add high
+
+SQRDMLAH_zzzz   01000100 .. 0 ..... 01110 0 ..... .....  @rda_rn_rm
+SQRDMLSH_zzzz   01000100 .. 0 ..... 01110 1 ..... .....  @rda_rn_rm

target/arm/translate-sve.c

@@ -7562,3 +7562,21 @@ static bool trans_SQDMLSLBT(DisasContext *s, arg_rrrr_esz *a)
 {
     return do_sqdmlsl_zzzw(s, a, false, true);
 }
+
+static bool trans_SQRDMLAH_zzzz(DisasContext *s, arg_rrrr_esz *a)
+{
+    static gen_helper_gvec_4 * const fns[] = {
+        gen_helper_sve2_sqrdmlah_b, gen_helper_sve2_sqrdmlah_h,
+        gen_helper_sve2_sqrdmlah_s, gen_helper_sve2_sqrdmlah_d,
+    };
+    return do_sve2_zzzz_ool(s, a, fns[a->esz], 0);
+}
+
+static bool trans_SQRDMLSH_zzzz(DisasContext *s, arg_rrrr_esz *a)
+{
+    static gen_helper_gvec_4 * const fns[] = {
+        gen_helper_sve2_sqrdmlsh_b, gen_helper_sve2_sqrdmlsh_h,
+        gen_helper_sve2_sqrdmlsh_s, gen_helper_sve2_sqrdmlsh_d,
+    };
+    return do_sve2_zzzz_ool(s, a, fns[a->esz], 0);
+}

target/arm/vec_helper.c

@@ -22,6 +22,7 @@
 #include "exec/helper-proto.h"
 #include "tcg/tcg-gvec-desc.h"
 #include "fpu/softfloat.h"
+#include "qemu/int128.h"
 #include "vec_internal.h"
 
 /* Note that vector data is stored in host-endian 64-bit chunks,
@@ -36,15 +37,55 @@
 #define H4(x)  (x)
 #endif
 
+/* Signed saturating rounding doubling multiply-accumulate high half, 8-bit */
+static int8_t do_sqrdmlah_b(int8_t src1, int8_t src2, int8_t src3,
+                            bool neg, bool round)
+{
+    /*
+     * Simplify:
+     * = ((a3 << 8) + ((e1 * e2) << 1) + (round << 7)) >> 8
+     * = ((a3 << 7) + (e1 * e2) + (round << 6)) >> 7
+     */
+    int32_t ret = (int32_t)src1 * src2;
+    if (neg) {
+        ret = -ret;
+    }
+    ret += ((int32_t)src3 << 7) + (round << 6);
+    ret >>= 7;
+
+    if (ret != (int8_t)ret) {
+        ret = (ret < 0 ? INT8_MIN : INT8_MAX);
+    }
+    return ret;
+}
+
+void HELPER(sve2_sqrdmlah_b)(void *vd, void *vn, void *vm,
+                             void *va, uint32_t desc)
+{
+    intptr_t i, opr_sz = simd_oprsz(desc);
+    int8_t *d = vd, *n = vn, *m = vm, *a = va;
+
+    for (i = 0; i < opr_sz; ++i) {
+        d[i] = do_sqrdmlah_b(n[i], m[i], a[i], false, true);
+    }
+}
+
+void HELPER(sve2_sqrdmlsh_b)(void *vd, void *vn, void *vm,
+                             void *va, uint32_t desc)
+{
+    intptr_t i, opr_sz = simd_oprsz(desc);
+    int8_t *d = vd, *n = vn, *m = vm, *a = va;
+
+    for (i = 0; i < opr_sz; ++i) {
+        d[i] = do_sqrdmlah_b(n[i], m[i], a[i], true, true);
+    }
+}
+
 /* Signed saturating rounding doubling multiply-accumulate high half, 16-bit */
 static int16_t do_sqrdmlah_h(int16_t src1, int16_t src2, int16_t src3,
                              bool neg, bool round, uint32_t *sat)
 {
-    /*
+    /* Simplify similarly to do_sqrdmlah_b above.  */
-     * Simplify:
-     * = ((a3 << 16) + ((e1 * e2) << 1) + (1 << 15)) >> 16
-     * = ((a3 << 15) + (e1 * e2) + (1 << 14)) >> 15
-     */
     int32_t ret = (int32_t)src1 * src2;
     if (neg) {
         ret = -ret;
@@ -133,11 +174,35 @@ void HELPER(neon_sqrdmulh_h)(void *vd, void *vn, void *vm,
     clear_tail(d, opr_sz, simd_maxsz(desc));
 }
 
+void HELPER(sve2_sqrdmlah_h)(void *vd, void *vn, void *vm,
+                             void *va, uint32_t desc)
+{
+    intptr_t i, opr_sz = simd_oprsz(desc);
+    int16_t *d = vd, *n = vn, *m = vm, *a = va;
+    uint32_t discard;
+
+    for (i = 0; i < opr_sz / 2; ++i) {
+        d[i] = do_sqrdmlah_h(n[i], m[i], a[i], false, true, &discard);
+    }
+}
+
+void HELPER(sve2_sqrdmlsh_h)(void *vd, void *vn, void *vm,
+                             void *va, uint32_t desc)
+{
+    intptr_t i, opr_sz = simd_oprsz(desc);
+    int16_t *d = vd, *n = vn, *m = vm, *a = va;
+    uint32_t discard;
+
+    for (i = 0; i < opr_sz / 2; ++i) {
+        d[i] = do_sqrdmlah_h(n[i], m[i], a[i], true, true, &discard);
+    }
+}
+
 /* Signed saturating rounding doubling multiply-accumulate high half, 32-bit */
 static int32_t do_sqrdmlah_s(int32_t src1, int32_t src2, int32_t src3,
                              bool neg, bool round, uint32_t *sat)
 {
-    /* Simplify similarly to int_qrdmlah_s16 above.  */
+    /* Simplify similarly to do_sqrdmlah_b above.  */
     int64_t ret = (int64_t)src1 * src2;
     if (neg) {
         ret = -ret;
@@ -220,6 +285,90 @@ void HELPER(neon_sqrdmulh_s)(void *vd, void *vn, void *vm,
     clear_tail(d, opr_sz, simd_maxsz(desc));
 }
 
+void HELPER(sve2_sqrdmlah_s)(void *vd, void *vn, void *vm,
+                             void *va, uint32_t desc)
+{
+    intptr_t i, opr_sz = simd_oprsz(desc);
+    int32_t *d = vd, *n = vn, *m = vm, *a = va;
+    uint32_t discard;
+
+    for (i = 0; i < opr_sz / 4; ++i) {
+        d[i] = do_sqrdmlah_s(n[i], m[i], a[i], false, true, &discard);
+    }
+}
+
+void HELPER(sve2_sqrdmlsh_s)(void *vd, void *vn, void *vm,
+                             void *va, uint32_t desc)
+{
+    intptr_t i, opr_sz = simd_oprsz(desc);
+    int32_t *d = vd, *n = vn, *m = vm, *a = va;
+    uint32_t discard;
+
+    for (i = 0; i < opr_sz / 4; ++i) {
+        d[i] = do_sqrdmlah_s(n[i], m[i], a[i], true, true, &discard);
+    }
+}
+
+/* Signed saturating rounding doubling multiply-accumulate high half, 64-bit */
+static int64_t do_sat128_d(Int128 r)
+{
+    int64_t ls = int128_getlo(r);
+    int64_t hs = int128_gethi(r);
+
+    if (unlikely(hs != (ls >> 63))) {
+        return hs < 0 ? INT64_MIN : INT64_MAX;
+    }
+    return ls;
+}
+
+static int64_t do_sqrdmlah_d(int64_t n, int64_t m, int64_t a,
+                             bool neg, bool round)
+{
+    uint64_t l, h;
+    Int128 r, t;
+
+    /* As in do_sqrdmlah_b, but with 128-bit arithmetic. */
+    muls64(&l, &h, m, n);
+    r = int128_make128(l, h);
+    if (neg) {
+        r = int128_neg(r);
+    }
+    if (a) {
+        t = int128_exts64(a);
+        t = int128_lshift(t, 63);
+        r = int128_add(r, t);
+    }
+    if (round) {
+        t = int128_exts64(1ll << 62);
+        r = int128_add(r, t);
+    }
+    r = int128_rshift(r, 63);
+
+    return do_sat128_d(r);
+}
+
+void HELPER(sve2_sqrdmlah_d)(void *vd, void *vn, void *vm,
+                             void *va, uint32_t desc)
+{
+    intptr_t i, opr_sz = simd_oprsz(desc);
+    int64_t *d = vd, *n = vn, *m = vm, *a = va;
+
+    for (i = 0; i < opr_sz / 8; ++i) {
+        d[i] = do_sqrdmlah_d(n[i], m[i], a[i], false, true);
+    }
+}
+
+void HELPER(sve2_sqrdmlsh_d)(void *vd, void *vn, void *vm,
+                             void *va, uint32_t desc)
+{
+    intptr_t i, opr_sz = simd_oprsz(desc);
+    int64_t *d = vd, *n = vn, *m = vm, *a = va;
+
+    for (i = 0; i < opr_sz / 8; ++i) {
+        d[i] = do_sqrdmlah_d(n[i], m[i], a[i], true, true);
+    }
+}
+
 /* Integer 8 and 16-bit dot-product.
  *
  * Note that for the loops herein, host endianness does not matter