target/ppc: Tidy helper_fsqrt

Tidy the invalid exception checking so that we rely on softfloat for
initial argument validation, and select the kind of invalid operand
exception only when we know we must.  Pass and return float64 values
directly rather than bounce through the CPU_DoubleU union.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

diff --git a/target/ppc/fpu_helper.c b/target/ppc/fpu_helper.c
index 7758372ecd9ffce89f348ef33b356089e245fc4a..44f3fed17d9dad8dc7e4b7ee0ca1b10da0fcd06a 100644 (file)
--- a/target/ppc/fpu_helper.c
+++ b/target/ppc/fpu_helper.c
@@ -858,25 +858,24 @@ uint64_t helper_frsp(CPUPPCState *env, uint64_t arg)
 }
 
 /* fsqrt - fsqrt. */
-uint64_t helper_fsqrt(CPUPPCState *env, uint64_t arg)
+float64 helper_fsqrt(CPUPPCState *env, float64 arg)
 {
-    CPU_DoubleU farg;
-
-    farg.ll = arg;
+    float64 ret = float64_sqrt(arg, &env->fp_status);
+    int status = get_float_exception_flags(&env->fp_status);
 
-    if (unlikely(float64_is_any_nan(farg.d))) {
-        if (unlikely(float64_is_signaling_nan(farg.d, &env->fp_status))) {
-            /* sNaN reciprocal square root */
-            float_invalid_op_excp(env, POWERPC_EXCP_FP_VXSNAN, 1);
-            farg.ll = float64_snan_to_qnan(farg.ll);
+    if (unlikely(status & float_flag_invalid)) {
+        if (unlikely(float64_is_any_nan(arg))) {
+            if (unlikely(float64_is_signaling_nan(arg, &env->fp_status))) {
+                /* sNaN square root */
+                float_invalid_op_excp(env, POWERPC_EXCP_FP_VXSNAN, 1);
+            }
+        } else {
+            /* Square root of a negative nonzero number */
+            float_invalid_op_excp(env, POWERPC_EXCP_FP_VXSQRT, 1);
         }
-    } else if (unlikely(float64_is_neg(farg.d) && !float64_is_zero(farg.d))) {
-        /* Square root of a negative nonzero number */
-        farg.ll = float_invalid_op_excp(env, POWERPC_EXCP_FP_VXSQRT, 1);
-    } else {
-        farg.d = float64_sqrt(farg.d, &env->fp_status);
     }
-    return farg.ll;
+
+    return ret;
 }
 
 /* fre - fre. */

diff --git a/target/ppc/helper.h b/target/ppc/helper.h
index d81806dd2c2d9613a70e8f7ce73e9943f40d1229..7ed72c2337fd07c00858ab772ebefb5aef903f6a 100644 (file)
--- a/target/ppc/helper.h
+++ b/target/ppc/helper.h
@@ -93,7 +93,7 @@ DEF_HELPER_4(fmadd, i64, env, i64, i64, i64)
 DEF_HELPER_4(fmsub, i64, env, i64, i64, i64)
 DEF_HELPER_4(fnmadd, i64, env, i64, i64, i64)
 DEF_HELPER_4(fnmsub, i64, env, i64, i64, i64)
-DEF_HELPER_2(fsqrt, i64, env, i64)
+DEF_HELPER_2(fsqrt, f64, env, f64)
 DEF_HELPER_2(fre, i64, env, i64)
 DEF_HELPER_2(fres, i64, env, i64)
 DEF_HELPER_2(frsqrte, i64, env, i64)