softfloat: Add flag specific to Inf * 0

PowerPC has this flag, and it's easier to compute it here
than after the fact.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211119160502.17432-4-richard.henderson@linaro.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

fpu/softfloat-parts.c.inc

@@ -423,7 +423,7 @@ static FloatPartsN *partsN(mul)(FloatPartsN *a, FloatPartsN *b,
 
     /* Inf * Zero == NaN */
     if (unlikely(ab_mask == float_cmask_infzero)) {
-        float_raise(float_flag_invalid, s);
+        float_raise(float_flag_invalid | float_flag_invalid_imz, s);
         parts_default_nan(a, s);
         return a;
     }
@@ -489,6 +489,7 @@ static FloatPartsN *partsN(muladd)(FloatPartsN *a, FloatPartsN *b,
 
     if (unlikely(ab_mask != float_cmask_normal)) {
         if (unlikely(ab_mask == float_cmask_infzero)) {
+            float_raise(float_flag_invalid | float_flag_invalid_imz, s);
             goto d_nan;
         }
 
@@ -567,7 +568,6 @@ static FloatPartsN *partsN(muladd)(FloatPartsN *a, FloatPartsN *b,
     goto finish_sign;
 
  d_nan:
-    float_raise(float_flag_invalid, s);
     parts_default_nan(a, s);
     return a;
 }

fpu/softfloat-specialize.c.inc

@@ -506,7 +506,7 @@ static int pickNaNMulAdd(FloatClass a_cls, FloatClass b_cls, FloatClass c_cls,
      * the default NaN
      */
     if (infzero && is_qnan(c_cls)) {
-        float_raise(float_flag_invalid, status);
+        float_raise(float_flag_invalid | float_flag_invalid_imz, status);
         return 3;
     }
 
@@ -533,7 +533,7 @@ static int pickNaNMulAdd(FloatClass a_cls, FloatClass b_cls, FloatClass c_cls,
          * case sets InvalidOp and returns the default NaN
          */
         if (infzero) {
-            float_raise(float_flag_invalid, status);
+            float_raise(float_flag_invalid | float_flag_invalid_imz, status);
             return 3;
         }
         /* Prefer sNaN over qNaN, in the a, b, c order. */
@@ -556,7 +556,7 @@ static int pickNaNMulAdd(FloatClass a_cls, FloatClass b_cls, FloatClass c_cls,
          * case sets InvalidOp and returns the input value 'c'
          */
         if (infzero) {
-            float_raise(float_flag_invalid, status);
+            float_raise(float_flag_invalid | float_flag_invalid_imz, status);
             return 2;
         }
         /* Prefer sNaN over qNaN, in the c, a, b order. */
@@ -580,7 +580,7 @@ static int pickNaNMulAdd(FloatClass a_cls, FloatClass b_cls, FloatClass c_cls,
      * a default NaN
      */
     if (infzero) {
-        float_raise(float_flag_invalid, status);
+        float_raise(float_flag_invalid | float_flag_invalid_imz, status);
         return 2;
     }
 
@@ -597,7 +597,7 @@ static int pickNaNMulAdd(FloatClass a_cls, FloatClass b_cls, FloatClass c_cls,
 #elif defined(TARGET_RISCV)
     /* For RISC-V, InvalidOp is set when multiplicands are Inf and zero */
     if (infzero) {
-        float_raise(float_flag_invalid, status);
+        float_raise(float_flag_invalid | float_flag_invalid_imz, status);
     }
     return 3; /* default NaN */
 #elif defined(TARGET_XTENSA)
@@ -606,7 +606,7 @@ static int pickNaNMulAdd(FloatClass a_cls, FloatClass b_cls, FloatClass c_cls,
      * an input NaN if we have one (ie c).
      */
     if (infzero) {
-        float_raise(float_flag_invalid, status);
+        float_raise(float_flag_invalid | float_flag_invalid_imz, status);
         return 2;
     }
     if (status->use_first_nan) {

include/fpu/softfloat-types.h

@@ -153,6 +153,7 @@ enum {
     float_flag_input_denormal  = 0x0020,
     float_flag_output_denormal = 0x0040,
     float_flag_invalid_isi     = 0x0080,  /* inf - inf */
+    float_flag_invalid_imz     = 0x0100,  /* inf * 0 */
 };
 
 /*