[PATCH] target/ppc: Merge COMPUTE_CLASS and COMPUTE_FPRF

[Richard Henderson]

Instead of computing an artifical "class" bitmask then
converting that to the fprf value, compute the final
value from the start.

Reorder the tests to check the most likely cases first.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/ppc/fpu_helper.c | 78 ++++++++++++-----------------------------
 1 file changed, 22 insertions(+), 56 deletions(-)

diff --git a/target/ppc/fpu_helper.c b/target/ppc/fpu_helper.c
index a66e16c212..03150a0f10 100644
--- a/target/ppc/fpu_helper.c
+++ b/target/ppc/fpu_helper.c
@@ -141,62 +141,28 @@ static inline int ppc_float64_get_unbiased_exp(float64 f)
     return ((f >> 52) & 0x7FF) - 1023;
 }
 
-/* Classify a floating-point number.  */
-enum {
-    is_normal   = 1,
-    is_zero     = 2,
-    is_denormal = 4,
-    is_inf      = 8,
-    is_qnan     = 16,
-    is_snan     = 32,
-    is_neg      = 64,
-};
-
-#define COMPUTE_CLASS(tp)                                      \
-static int tp##_classify(tp arg)                               \
-{                                                              \
-    int ret = tp##_is_neg(arg) * is_neg;                       \
-    if (unlikely(tp##_is_any_nan(arg))) {                      \
-        float_status dummy = { };  /* snan_bit_is_one = 0 */   \
-        ret |= (tp##_is_signaling_nan(arg, &dummy)             \
-                ? is_snan : is_qnan);                          \
-    } else if (unlikely(tp##_is_infinity(arg))) {              \
-        ret |= is_inf;                                         \
-    } else if (tp##_is_zero(arg)) {                            \
-        ret |= is_zero;                                        \
-    } else if (tp##_is_zero_or_denormal(arg)) {                \
-        ret |= is_denormal;                                    \
-    } else {                                                   \
-        ret |= is_normal;                                      \
-    }                                                          \
-    return ret;                                                \
-}
-
-COMPUTE_CLASS(float16)
-COMPUTE_CLASS(float32)
-COMPUTE_CLASS(float64)
-COMPUTE_CLASS(float128)
-
-static void set_fprf_from_class(CPUPPCState *env, int class)
-{
-    static const uint8_t fprf[6][2] = {
-        { 0x04, 0x08 },  /* normalized */
-        { 0x02, 0x12 },  /* zero */
-        { 0x14, 0x18 },  /* denormalized */
-        { 0x05, 0x09 },  /* infinity */
-        { 0x11, 0x11 },  /* qnan */
-        { 0x00, 0x00 },  /* snan -- flags are undefined */
-    };
-    bool isneg = class & is_neg;
-
-    env->fpscr &= ~FP_FPRF;
-    env->fpscr |= fprf[ctz32(class)][isneg] << FPSCR_FPRF;
-}
-
-#define COMPUTE_FPRF(tp)                                \
-void helper_compute_fprf_##tp(CPUPPCState *env, tp arg) \
-{                                                       \
-    set_fprf_from_class(env, tp##_classify(arg));       \
+#define COMPUTE_FPRF(tp)                                          \
+void helper_compute_fprf_##tp(CPUPPCState *env, tp arg)           \
+{                                                                 \
+    bool neg = tp##_is_neg(arg);                                  \
+    target_ulong fprf;                                            \
+    if (likely(tp##_is_normal(arg))) {                            \
+        fprf = neg ? 0x08 << FPSCR_FPRF : 0x04 << FPSCR_FPRF;     \
+    } else if (tp##_is_zero(arg)) {                               \
+        fprf = neg ? 0x12 << FPSCR_FPRF : 0x02 << FPSCR_FPRF;     \
+    } else if (tp##_is_zero_or_denormal(arg)) {                   \
+        fprf = neg ? 0x18 << FPSCR_FPRF : 0x14 << FPSCR_FPRF;     \
+    } else if (tp##_is_infinity(arg)) {                           \
+        fprf = neg ? 0x09 << FPSCR_FPRF : 0x05 << FPSCR_FPRF;     \
+    } else {                                                      \
+        float_status dummy = { };  /* snan_bit_is_one = 0 */      \
+        if (tp##_is_signaling_nan(arg, &dummy)) {                 \
+            fprf = 0x00 << FPSCR_FPRF;                            \
+        } else {                                                  \
+            fprf = 0x11 << FPSCR_FPRF;                            \
+        }                                                         \
+    }                                                             \
+    env->fpscr = (env->fpscr & ~FP_FPRF) | fprf;                  \
 }
 
 COMPUTE_FPRF(float16)
-- 
2.34.1