| Message ID | 1485504213-21632-2-git-send-email-bharata@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 27 January 2017 at 08:03, Bharata B Rao <bharata@linux.vnet.ibm.com> wrote: > When rounding a floating point result to float64 precision, the > existing code doesn't re-calculate the required round increment > for the underflow case. Fix this. > > Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> > --- > fpu/softfloat.c | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/fpu/softfloat.c b/fpu/softfloat.c > index c295f31..b04699c 100644 > --- a/fpu/softfloat.c > +++ b/fpu/softfloat.c > @@ -651,6 +651,23 @@ static float64 roundAndPackFloat64(flag zSign, int zExp, uint64_t zSig, > if (isTiny && roundBits) { > float_raise(float_flag_underflow, status); > } > + switch (roundingMode) { > + case float_round_nearest_even: > + case float_round_ties_away: > + roundIncrement = 0x200; > + break; > + case float_round_to_zero: > + roundIncrement = 0; > + break; > + case float_round_up: > + roundIncrement = zSign ? 0 : 0x3ff; > + break; > + case float_round_down: > + roundIncrement = zSign ? 0x3ff : 0; > + break; > + default: > + abort(); > + } > } > } > if (roundBits) { When does this give a different value to what roundIncrement was before? As far as I can see the only data-dependency here is on zSign, and underflowing doesn't affect zSign. thanks -- PMM
diff --git a/fpu/softfloat.c b/fpu/softfloat.c index c295f31..b04699c 100644 --- a/fpu/softfloat.c +++ b/fpu/softfloat.c @@ -651,6 +651,23 @@ static float64 roundAndPackFloat64(flag zSign, int zExp, uint64_t zSig, if (isTiny && roundBits) { float_raise(float_flag_underflow, status); } + switch (roundingMode) { + case float_round_nearest_even: + case float_round_ties_away: + roundIncrement = 0x200; + break; + case float_round_to_zero: + roundIncrement = 0; + break; + case float_round_up: + roundIncrement = zSign ? 0 : 0x3ff; + break; + case float_round_down: + roundIncrement = zSign ? 0x3ff : 0; + break; + default: + abort(); + } } } if (roundBits) {
When rounding a floating point result to float64 precision, the existing code doesn't re-calculate the required round increment for the underflow case. Fix this. Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> --- fpu/softfloat.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)