diff mbox series

[v1,05/11] fpu: Add float_round_to_odd_inf

Message ID 20210416235928.1631788-6-richard.henderson@linaro.org
State New
Headers show
Series target/arm: Implement BFloat16 | expand

Commit Message

Richard Henderson April 16, 2021, 11:59 p.m. UTC
For Arm BFDOT and BFMMLA, we need a version of round-to-odd
that overflows to infinity, instead of the max normal number.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 include/fpu/softfloat-types.h | 4 +++-
 fpu/softfloat.c               | 8 ++++++--
 2 files changed, 9 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/include/fpu/softfloat-types.h b/include/fpu/softfloat-types.h
index 8a3f20fae9..3b757c3d6a 100644
--- a/include/fpu/softfloat-types.h
+++ b/include/fpu/softfloat-types.h
@@ -134,8 +134,10 @@  typedef enum __attribute__((__packed__)) {
     float_round_up           = 2,
     float_round_to_zero      = 3,
     float_round_ties_away    = 4,
-    /* Not an IEEE rounding mode: round to the closest odd mantissa value */
+    /* Not an IEEE rounding mode: round to closest odd, overflow to max */
     float_round_to_odd       = 5,
+    /* Not an IEEE rounding mode: round to closest odd, overflow to inf */
+    float_round_to_odd_inf   = 6,
 } FloatRoundMode;
 
 /*
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 67cfa0fd82..76097679b0 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -694,13 +694,12 @@  static FloatParts round_canonical(FloatParts p, float_status *s,
 
     switch (p.cls) {
     case float_class_normal:
+        overflow_norm = false;
         switch (s->float_rounding_mode) {
         case float_round_nearest_even:
-            overflow_norm = false;
             inc = ((frac & roundeven_mask) != frac_lsbm1 ? frac_lsbm1 : 0);
             break;
         case float_round_ties_away:
-            overflow_norm = false;
             inc = frac_lsbm1;
             break;
         case float_round_to_zero:
@@ -717,6 +716,8 @@  static FloatParts round_canonical(FloatParts p, float_status *s,
             break;
         case float_round_to_odd:
             overflow_norm = true;
+            /* fall through */
+        case float_round_to_odd_inf:
             inc = frac & frac_lsb ? 0 : round_mask;
             break;
         default:
@@ -771,6 +772,7 @@  static FloatParts round_canonical(FloatParts p, float_status *s,
                            ? frac_lsbm1 : 0);
                     break;
                 case float_round_to_odd:
+                case float_round_to_odd_inf:
                     inc = frac & frac_lsb ? 0 : round_mask;
                     break;
                 default:
@@ -6860,6 +6862,8 @@  float128 float128_round_to_int(float128 a, float_status *status)
 
             case float_round_to_zero:
                 break;
+            default:
+                g_assert_not_reached();
             }
             return packFloat128( aSign, 0, 0, 0 );
         }