target/ppc: Tidy helper_fadd, helper_fsub

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.

Note that because we know float_flag_invalid was set, we do not have
to re-check the signs of the infinities.
Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>

target/ppc/fpu_helper.c

@@ -587,51 +587,43 @@ void helper_reset_fpstatus(CPUPPCState *env)
 }
 
 /* fadd - fadd. */
-uint64_t helper_fadd(CPUPPCState *env, uint64_t arg1, uint64_t arg2)
+float64 helper_fadd(CPUPPCState *env, float64 arg1, float64 arg2)
 {
-    CPU_DoubleU farg1, farg2;
-
-    farg1.ll = arg1;
-    farg2.ll = arg2;
+    float64 ret = float64_add(arg1, arg2, &env->fp_status);
+    int status = get_float_exception_flags(&env->fp_status);
 
-    if (unlikely(float64_is_infinity(farg1.d) && float64_is_infinity(farg2.d) &&
-                 float64_is_neg(farg1.d) != float64_is_neg(farg2.d))) {
-        /* Magnitude subtraction of infinities */
-        farg1.ll = float_invalid_op_excp(env, POWERPC_EXCP_FP_VXISI, 1);
-    } else {
-        if (unlikely(float64_is_signaling_nan(farg1.d, &env->fp_status) ||
-                     float64_is_signaling_nan(farg2.d, &env->fp_status))) {
+    if (unlikely(status & float_flag_invalid)) {
+        if (float64_is_infinity(arg1) && float64_is_infinity(arg2)) {
+            /* Magnitude subtraction of infinities */
+            float_invalid_op_excp(env, POWERPC_EXCP_FP_VXISI, 1);
+        } else if (float64_is_signaling_nan(arg1, &env->fp_status) ||
+                   float64_is_signaling_nan(arg2, &env->fp_status)) {
             /* sNaN addition */
             float_invalid_op_excp(env, POWERPC_EXCP_FP_VXSNAN, 1);
         }
-        farg1.d = float64_add(farg1.d, farg2.d, &env->fp_status);
     }
 
-    return farg1.ll;
+    return ret;
 }
 
 /* fsub - fsub. */
-uint64_t helper_fsub(CPUPPCState *env, uint64_t arg1, uint64_t arg2)
+float64 helper_fsub(CPUPPCState *env, float64 arg1, float64 arg2)
 {
-    CPU_DoubleU farg1, farg2;
-
-    farg1.ll = arg1;
-    farg2.ll = arg2;
+    float64 ret = float64_sub(arg1, arg2, &env->fp_status);
+    int status = get_float_exception_flags(&env->fp_status);
 
-    if (unlikely(float64_is_infinity(farg1.d) && float64_is_infinity(farg2.d) &&
-                 float64_is_neg(farg1.d) == float64_is_neg(farg2.d))) {
-        /* Magnitude subtraction of infinities */
-        farg1.ll = float_invalid_op_excp(env, POWERPC_EXCP_FP_VXISI, 1);
-    } else {
-        if (unlikely(float64_is_signaling_nan(farg1.d, &env->fp_status) ||
-                     float64_is_signaling_nan(farg2.d, &env->fp_status))) {
-            /* sNaN subtraction */
+    if (unlikely(status & float_flag_invalid)) {
+        if (float64_is_infinity(arg1) && float64_is_infinity(arg2)) {
+            /* Magnitude subtraction of infinities */
+            float_invalid_op_excp(env, POWERPC_EXCP_FP_VXISI, 1);
+        } else if (float64_is_signaling_nan(arg1, &env->fp_status) ||
+                   float64_is_signaling_nan(arg2, &env->fp_status)) {
+            /* sNaN addition */
             float_invalid_op_excp(env, POWERPC_EXCP_FP_VXSNAN, 1);
         }
-        farg1.d = float64_sub(farg1.d, farg2.d, &env->fp_status);
     }
 
-    return farg1.ll;
+    return ret;
 }
 
 /* fmul - fmul. */

target/ppc/helper.h

@@ -85,8 +85,8 @@ DEF_HELPER_2(friz, i64, env, i64)
 DEF_HELPER_2(frip, i64, env, i64)
 DEF_HELPER_2(frim, i64, env, i64)
 
-DEF_HELPER_3(fadd, i64, env, i64, i64)
-DEF_HELPER_3(fsub, i64, env, i64, i64)
+DEF_HELPER_3(fadd, f64, env, f64, f64)
+DEF_HELPER_3(fsub, f64, env, f64, f64)
 DEF_HELPER_3(fmul, f64, env, f64, f64)
 DEF_HELPER_3(fdiv, f64, env, f64, f64)
 DEF_HELPER_4(fmadd, i64, env, i64, i64, i64)