softfpu: Add float_round_to_odd_inf

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>
This commit is contained in:
Richard Henderson 2021-05-25 15:58:10 -07:00 committed by Peter Maydell
parent d29b17ca3e
commit 60c8f7265d
2 changed files with 7 additions and 3 deletions

View File

@ -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:

View File

@ -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;
/*