From: Richard Henderson <richard.henderson@linaro.org>
For Arm BFDOT and BFMMLA, we need a version of round-to-odd
that overflows to infinity, instead of the max normal number.
Cc: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20210525225817.400336-6-richard.henderson@linaro.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
include/fpu/softfloat-types.h | 4 +++-
fpu/softfloat-parts.c.inc | 6 ++++--
2 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/include/fpu/softfloat-types.h b/include/fpu/softfloat-types.h
index 8a3f20fae9e..3b757c3d6a6 100644
@@ -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-parts.c.inc b/fpu/softfloat-parts.c.inc
index a897a5a743d..7f69da1d8fa 100644
@@ -176,13 +176,12 @@ static void partsN(uncanon)(FloatPartsN *p, float_status *s,
g_assert_not_reached();
}
+ overflow_norm = false;
switch (s->float_rounding_mode) {
case float_round_nearest_even:
- overflow_norm = false;
inc = ((p->frac_lo & 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:
@@ -199,6 +198,8 @@ static void partsN(uncanon)(FloatPartsN *p, float_status *s,
break;
case float_round_to_odd:
overflow_norm = true;
+ /* fall through */
+ case float_round_to_odd_inf:
inc = p->frac_lo & frac_lsb ? 0 : round_mask;
break;
default:
@@ -259,6 +260,7 @@ static void partsN(uncanon)(FloatPartsN *p, float_status *s,
? frac_lsbm1 : 0);
break;
case float_round_to_odd:
+ case float_round_to_odd_inf:
inc = p->frac_lo & frac_lsb ? 0 : round_mask;
break;
default:
--
2.20.1