target/sparc: Split out do_ms16b

The unit operation for fmul8x16 and friends is described in the
manual as "MS16b".  Split that out for clarity.  Improve rounding
with an unconditional addition of 0.5 as a fixed-point integer.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20240502165528.244004-8-richard.henderson@linaro.org>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

1 files changed, 24 insertions, 54 deletions

diff --git a/target/sparc/vis_helper.c b/target/sparc/vis_helper.c
index 14c665cad6..e15c6bb34e 100644
--- a/target/sparc/vis_helper.c
+++ b/target/sparc/vis_helper.c
@@ -44,6 +44,7 @@ target_ulong helper_array8(target_ulong pixel_addr, target_ulong cubesize)
 
 #if HOST_BIG_ENDIAN
 #define VIS_B64(n) b[7 - (n)]
+#define VIS_SB64(n) sb[7 - (n)]
 #define VIS_W64(n) w[3 - (n)]
 #define VIS_SW64(n) sw[3 - (n)]
 #define VIS_L64(n) l[1 - (n)]
@@ -51,6 +52,7 @@ target_ulong helper_array8(target_ulong pixel_addr, target_ulong cubesize)
 #define VIS_W32(n) w[1 - (n)]
 #else
 #define VIS_B64(n) b[n]
+#define VIS_SB64(n) sb[n]
 #define VIS_W64(n) w[n]
 #define VIS_SW64(n) sw[n]
 #define VIS_L64(n) l[n]
@@ -60,6 +62,7 @@ target_ulong helper_array8(target_ulong pixel_addr, target_ulong cubesize)
 
 typedef union {
     uint8_t b[8];
+    int8_t sb[8];
     uint16_t w[4];
     int16_t sw[4];
     uint32_t l[2];
@@ -95,27 +98,23 @@ uint64_t helper_fpmerge(uint32_t src1, uint32_t src2)
     return d.ll;
 }
 
+static inline int do_ms16b(int x, int y)
+{
+    return ((x * y) + 0x80) >> 8;
+}
+
 uint64_t helper_fmul8x16(uint32_t src1, uint64_t src2)
 {
     VIS64 d;
     VIS32 s;
-    uint32_t tmp;
 
     s.l = src1;
     d.ll = src2;
 
-#define PMUL(r)                                                 \
-    tmp = (int32_t)d.VIS_SW64(r) * (int32_t)s.VIS_B32(r);       \
-    if ((tmp & 0xff) > 0x7f) {                                  \
-        tmp += 0x100;                                           \
-    }                                                           \
-    d.VIS_W64(r) = tmp >> 8;
-
-    PMUL(0);
-    PMUL(1);
-    PMUL(2);
-    PMUL(3);
-#undef PMUL
+    d.VIS_W64(0) = do_ms16b(s.VIS_B32(0), d.VIS_SW64(0));
+    d.VIS_W64(1) = do_ms16b(s.VIS_B32(1), d.VIS_SW64(1));
+    d.VIS_W64(2) = do_ms16b(s.VIS_B32(2), d.VIS_SW64(2));
+    d.VIS_W64(3) = do_ms16b(s.VIS_B32(3), d.VIS_SW64(3));
 
     return d.ll;
 }
@@ -124,25 +123,14 @@ uint64_t helper_fmul8x16a(uint32_t src1, int32_t src2)
 {
     VIS32 s;
     VIS64 d;
-    uint32_t tmp;
 
     s.l = src1;
     d.ll = 0;
 
-#define PMUL(r)                                \
-    do {                                       \
-        tmp = src2 * (int32_t)s.VIS_B32(r);    \
-        if ((tmp & 0xff) > 0x7f) {             \
-            tmp += 0x100;                      \
-        }                                      \
-        d.VIS_W64(r) = tmp >> 8;               \
-    } while (0)
-
-    PMUL(0);
-    PMUL(1);
-    PMUL(2);
-    PMUL(3);
-#undef PMUL
+    d.VIS_W64(0) = do_ms16b(s.VIS_B32(0), src2);
+    d.VIS_W64(1) = do_ms16b(s.VIS_B32(1), src2);
+    d.VIS_W64(2) = do_ms16b(s.VIS_B32(2), src2);
+    d.VIS_W64(3) = do_ms16b(s.VIS_B32(3), src2);
 
     return d.ll;
 }
@@ -150,23 +138,14 @@ uint64_t helper_fmul8x16a(uint32_t src1, int32_t src2)
 uint64_t helper_fmul8sux16(uint64_t src1, uint64_t src2)
 {
     VIS64 s, d;
-    uint32_t tmp;
 
     s.ll = src1;
     d.ll = src2;
 
-#define PMUL(r)                                                         \
-    tmp = (int32_t)d.VIS_SW64(r) * ((int32_t)s.VIS_SW64(r) >> 8);       \
-    if ((tmp & 0xff) > 0x7f) {                                          \
-        tmp += 0x100;                                                   \
-    }                                                                   \
-    d.VIS_W64(r) = tmp >> 8;
-
-    PMUL(0);
-    PMUL(1);
-    PMUL(2);
-    PMUL(3);
-#undef PMUL
+    d.VIS_W64(0) = do_ms16b(s.VIS_SB64(1), d.VIS_SW64(0));
+    d.VIS_W64(1) = do_ms16b(s.VIS_SB64(3), d.VIS_SW64(1));
+    d.VIS_W64(2) = do_ms16b(s.VIS_SB64(5), d.VIS_SW64(2));
+    d.VIS_W64(3) = do_ms16b(s.VIS_SB64(7), d.VIS_SW64(3));
 
     return d.ll;
 }
@@ -174,23 +153,14 @@ uint64_t helper_fmul8sux16(uint64_t src1, uint64_t src2)
 uint64_t helper_fmul8ulx16(uint64_t src1, uint64_t src2)
 {
     VIS64 s, d;
-    uint32_t tmp;
 
     s.ll = src1;
     d.ll = src2;
 
-#define PMUL(r)                                                         \
-    tmp = (int32_t)d.VIS_SW64(r) * ((uint32_t)s.VIS_B64(r * 2));        \
-    if ((tmp & 0xff) > 0x7f) {                                          \
-        tmp += 0x100;                                                   \
-    }                                                                   \
-    d.VIS_W64(r) = tmp >> 8;
-
-    PMUL(0);
-    PMUL(1);
-    PMUL(2);
-    PMUL(3);
-#undef PMUL
+    d.VIS_W64(0) = do_ms16b(s.VIS_B64(0), d.VIS_SW64(0));
+    d.VIS_W64(1) = do_ms16b(s.VIS_B64(2), d.VIS_SW64(1));
+    d.VIS_W64(2) = do_ms16b(s.VIS_B64(4), d.VIS_SW64(2));
+    d.VIS_W64(3) = do_ms16b(s.VIS_B64(6), d.VIS_SW64(3));
 
     return d.ll;
 }