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: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
qemu · Aug 21, 2018 · ac43cec · ac43cec
1 parent 79f9163
commit ac43cec
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Showing 2 changed files with 23 additions and 31 deletions.
diff --git a/target/ppc/fpu_helper.c b/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. */

diff --git a/target/ppc/helper.h b/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)