Handle the FPCR.AH semantics that we do not change the sign of an
input NaN in the FRECPS and FRSQRTS scalar insns, by providing
new helper functions that do the CHS part of the operation
differently.
Since the extra helper functions would be very repetitive if written
out longhand, we condense them and the existing non-AH helpers into
being emitted via macros.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
The negation steps in FCADD must honour FPCR.AH's "don't change the
sign of a NaN" semantics. Implement this in the same way we did for
the base ASIMD FCADD, by encoding FPCR.AH into the SIMD data field
passed to the helper and using that to decide whether to negate the
values.
The construction of neg_imag and neg_real were done to make it easy
to apply both in parallel with two simple logical operations. This
changed with FPCR.AH, which is more complex than that. Switch to
an approach that follows the pseudocode more closely, by extracting
the 'rot=1' parameter from the SIMD data field and changing the
sign of the appropriate input value.
Note that there was a naming issue with neg_imag and neg_real.
They were named backward, with neg_imag being non-zero for rot=1,
and vice versa. This was combined with reversed usage within the
loop, so that the negation in the end turned out correct.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
We use bfdotadd() in four callsites for various helper functions. Currently
this all assumes that we have the FPCR.EBF=0 semantics. For FPCR.EBF=1
we will need to:
* call a different routine to bfdotadd() because we need to do a
fused multiply-add rather than separate multiply and add steps
* use a different float_status that honours the FPCR rounding mode
and denormal-flushing fields
* pass in an extra float_status that has been set up to perform
round-to-odd rounding
To prepare for this, refactor all the callsites so that instead of
for (...) {
x = bfdotadd(...);
}
they are:
float_status fpst, fpst_odd;
if (is_ebf(env, &fpst, &fpst_odd)) {
for (...) {
x = bfdotadd_ebf(..., &fpst, &fpst_odd);
}
} else {
for (...) {
x = bfdotadd(..., &fpst);
}
}
For the moment the is_ebf() function always returns false, sets up
fpst for EBF=0 semantics and never sets up fpst_odd; bfdotadd_ebf()
will assert if called. We'll fill in the handling for EBF=1 in the
next commit.
This change should be a zero-behaviour-change refactor.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Use generic routines for 16-bit carry-less multiply.
Remove our local version of pmull_w.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Use generic routines for 8-bit carry-less multiply.
Remove our local version of pmull_h.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
