softfloat: Add flags specific to Inf / Inf and 0 / 0

PowerPC has these flags, and it's easier to compute them here
than after the fact.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211119160502.17432-5-richard.henderson@linaro.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

fpu/softfloat-parts.c.inc

@@ -590,11 +590,13 @@ static FloatPartsN *partsN(div)(FloatPartsN *a, FloatPartsN *b,
     }
 
     /* 0/0 or Inf/Inf => NaN */
-    if (unlikely(ab_mask == float_cmask_zero) ||
-        unlikely(ab_mask == float_cmask_inf)) {
-        float_raise(float_flag_invalid, s);
-        parts_default_nan(a, s);
-        return a;
+    if (unlikely(ab_mask == float_cmask_zero)) {
+        float_raise(float_flag_invalid | float_flag_invalid_zdz, s);
+        goto d_nan;
+    }
+    if (unlikely(ab_mask == float_cmask_inf)) {
+        float_raise(float_flag_invalid | float_flag_invalid_idi, s);
+        goto d_nan;
     }
 
     /* All the NaN cases */
@@ -625,6 +627,10 @@ static FloatPartsN *partsN(div)(FloatPartsN *a, FloatPartsN *b,
     float_raise(float_flag_divbyzero, s);
     a->cls = float_class_inf;
     return a;
+
+ d_nan:
+    parts_default_nan(a, s);
+    return a;
 }
 
 /*

include/fpu/softfloat-types.h

@@ -154,6 +154,8 @@ enum {
     float_flag_output_denormal = 0x0040,
     float_flag_invalid_isi     = 0x0080,  /* inf - inf */
     float_flag_invalid_imz     = 0x0100,  /* inf * 0 */
+    float_flag_invalid_idi     = 0x0200,  /* inf / inf */
+    float_flag_invalid_zdz     = 0x0400,  /* 0 / 0 */
 };
 
 /*