target/arm: Generalize inl_qrdmlah_* helper functions

Unify add/sub helpers and add a parameter for rounding.
This will allow saturating non-rounding to reuse this code.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
[PMM: fixed accidental use of '=' rather than '+=' in do_sqrdmlah_s]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20200815013145.539409-15-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

target/arm/vec_helper.c

@@ -37,19 +37,24 @@
 #endif
 
 /* Signed saturating rounding doubling multiply-accumulate high half, 16-bit */
-static int16_t inl_qrdmlah_s16(int16_t src1, int16_t src2,
-                               int16_t src3, uint32_t *sat)
+static int16_t do_sqrdmlah_h(int16_t src1, int16_t src2, int16_t src3,
+                             bool neg, bool round, uint32_t *sat)
 {
-    /* Simplify:
+    /*
+     * Simplify:
      * = ((a3 << 16) + ((e1 * e2) << 1) + (1 << 15)) >> 16
      * = ((a3 << 15) + (e1 * e2) + (1 << 14)) >> 15
      */
     int32_t ret = (int32_t)src1 * src2;
-    ret = ((int32_t)src3 << 15) + ret + (1 << 14);
+    if (neg) {
+        ret = -ret;
+    }
+    ret += ((int32_t)src3 << 15) + (round << 14);
     ret >>= 15;
+
     if (ret != (int16_t)ret) {
         *sat = 1;
-        ret = (ret < 0 ? -0x8000 : 0x7fff);
+        ret = (ret < 0 ? INT16_MIN : INT16_MAX);
     }
     return ret;
 }
@@ -58,8 +63,9 @@ uint32_t HELPER(neon_qrdmlah_s16)(CPUARMState *env, uint32_t src1,
                                   uint32_t src2, uint32_t src3)
 {
     uint32_t *sat = &env->vfp.qc[0];
-    uint16_t e1 = inl_qrdmlah_s16(src1, src2, src3, sat);
-    uint16_t e2 = inl_qrdmlah_s16(src1 >> 16, src2 >> 16, src3 >> 16, sat);
+    uint16_t e1 = do_sqrdmlah_h(src1, src2, src3, false, true, sat);
+    uint16_t e2 = do_sqrdmlah_h(src1 >> 16, src2 >> 16, src3 >> 16,
+                                false, true, sat);
     return deposit32(e1, 16, 16, e2);
 }
 
@@ -73,35 +79,18 @@ void HELPER(gvec_qrdmlah_s16)(void *vd, void *vn, void *vm,
     uintptr_t i;
 
     for (i = 0; i < opr_sz / 2; ++i) {
-        d[i] = inl_qrdmlah_s16(n[i], m[i], d[i], vq);
+        d[i] = do_sqrdmlah_h(n[i], m[i], d[i], false, true, vq);
     }
     clear_tail(d, opr_sz, simd_maxsz(desc));
 }
 
-/* Signed saturating rounding doubling multiply-subtract high half, 16-bit */
-static int16_t inl_qrdmlsh_s16(int16_t src1, int16_t src2,
-                               int16_t src3, uint32_t *sat)
-{
-    /* Similarly, using subtraction:
-     * = ((a3 << 16) - ((e1 * e2) << 1) + (1 << 15)) >> 16
-     * = ((a3 << 15) - (e1 * e2) + (1 << 14)) >> 15
-     */
-    int32_t ret = (int32_t)src1 * src2;
-    ret = ((int32_t)src3 << 15) - ret + (1 << 14);
-    ret >>= 15;
-    if (ret != (int16_t)ret) {
-        *sat = 1;
-        ret = (ret < 0 ? -0x8000 : 0x7fff);
-    }
-    return ret;
-}
-
 uint32_t HELPER(neon_qrdmlsh_s16)(CPUARMState *env, uint32_t src1,
                                   uint32_t src2, uint32_t src3)
 {
     uint32_t *sat = &env->vfp.qc[0];
-    uint16_t e1 = inl_qrdmlsh_s16(src1, src2, src3, sat);
-    uint16_t e2 = inl_qrdmlsh_s16(src1 >> 16, src2 >> 16, src3 >> 16, sat);
+    uint16_t e1 = do_sqrdmlah_h(src1, src2, src3, true, true, sat);
+    uint16_t e2 = do_sqrdmlah_h(src1 >> 16, src2 >> 16, src3 >> 16,
+                                true, true, sat);
     return deposit32(e1, 16, 16, e2);
 }
 
@@ -115,19 +104,23 @@ void HELPER(gvec_qrdmlsh_s16)(void *vd, void *vn, void *vm,
     uintptr_t i;
 
     for (i = 0; i < opr_sz / 2; ++i) {
-        d[i] = inl_qrdmlsh_s16(n[i], m[i], d[i], vq);
+        d[i] = do_sqrdmlah_h(n[i], m[i], d[i], true, true, vq);
     }
     clear_tail(d, opr_sz, simd_maxsz(desc));
 }
 
 /* Signed saturating rounding doubling multiply-accumulate high half, 32-bit */
-static int32_t inl_qrdmlah_s32(int32_t src1, int32_t src2,
-                               int32_t src3, uint32_t *sat)
+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.  */
     int64_t ret = (int64_t)src1 * src2;
-    ret = ((int64_t)src3 << 31) + ret + (1 << 30);
+    if (neg) {
+        ret = -ret;
+    }
+    ret += ((int64_t)src3 << 31) + (round << 30);
     ret >>= 31;
+
     if (ret != (int32_t)ret) {
         *sat = 1;
         ret = (ret < 0 ? INT32_MIN : INT32_MAX);
@@ -139,7 +132,7 @@ uint32_t HELPER(neon_qrdmlah_s32)(CPUARMState *env, int32_t src1,
                                   int32_t src2, int32_t src3)
 {
     uint32_t *sat = &env->vfp.qc[0];
-    return inl_qrdmlah_s32(src1, src2, src3, sat);
+    return do_sqrdmlah_s(src1, src2, src3, false, true, sat);
 }
 
 void HELPER(gvec_qrdmlah_s32)(void *vd, void *vn, void *vm,
@@ -152,31 +145,16 @@ void HELPER(gvec_qrdmlah_s32)(void *vd, void *vn, void *vm,
     uintptr_t i;
 
     for (i = 0; i < opr_sz / 4; ++i) {
-        d[i] = inl_qrdmlah_s32(n[i], m[i], d[i], vq);
+        d[i] = do_sqrdmlah_s(n[i], m[i], d[i], false, true, vq);
     }
     clear_tail(d, opr_sz, simd_maxsz(desc));
 }
 
-/* Signed saturating rounding doubling multiply-subtract high half, 32-bit */
-static int32_t inl_qrdmlsh_s32(int32_t src1, int32_t src2,
-                               int32_t src3, uint32_t *sat)
-{
-    /* Simplify similarly to int_qrdmlsh_s16 above.  */
-    int64_t ret = (int64_t)src1 * src2;
-    ret = ((int64_t)src3 << 31) - ret + (1 << 30);
-    ret >>= 31;
-    if (ret != (int32_t)ret) {
-        *sat = 1;
-        ret = (ret < 0 ? INT32_MIN : INT32_MAX);
-    }
-    return ret;
-}
-
 uint32_t HELPER(neon_qrdmlsh_s32)(CPUARMState *env, int32_t src1,
                                   int32_t src2, int32_t src3)
 {
     uint32_t *sat = &env->vfp.qc[0];
-    return inl_qrdmlsh_s32(src1, src2, src3, sat);
+    return do_sqrdmlah_s(src1, src2, src3, true, true, sat);
 }
 
 void HELPER(gvec_qrdmlsh_s32)(void *vd, void *vn, void *vm,
@@ -189,7 +167,7 @@ void HELPER(gvec_qrdmlsh_s32)(void *vd, void *vn, void *vm,
     uintptr_t i;
 
     for (i = 0; i < opr_sz / 4; ++i) {
-        d[i] = inl_qrdmlsh_s32(n[i], m[i], d[i], vq);
+        d[i] = do_sqrdmlah_s(n[i], m[i], d[i], true, true, vq);
     }
     clear_tail(d, opr_sz, simd_maxsz(desc));
 }