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QEMU main repository: Please see https://www.qemu.org/docs/master/devel/submitting-a-patch.html for how to submit changes to QEMU. Pull Requests are ignored. Please only use release tarballs from the QEMU website. http://www.qemu.org

emulation kvm qemu virtualization

Tree: 330c729571

History

Kito Cheng 896f51fbfa hardfloat: fix float32/64 fused multiply-add Before falling back to softfloat FMA, we do not restore the original values of inputs A and C. Fix it. This bug was caught by running gcc's testsuite on RISC-V qemu. Note that this change gives a small perf increase for fp-bench: Host: Intel(R) Core(TM) i7-4790K CPU @ 4.00GHz Command: perf stat -r 3 taskset -c 0 ./fp-bench -o mulAdd -p $prec - $prec = single: - before: 101.71 MFlops 102.18 MFlops 100.96 MFlops - after: 103.63 MFlops 103.05 MFlops 102.96 MFlops - $prec = double: - before: 173.10 MFlops 173.93 MFlops 172.11 MFlops - after: 178.49 MFlops 178.88 MFlops 178.66 MFlops Signed-off-by: Kito Cheng <kito.cheng@gmail.com> Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <20190322204320.17777-1-cota@braap.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>	7 years ago
..
softfloat-specialize.h	target/mips: Fix minor bug in FPU	7 years ago
softfloat.c	hardfloat: fix float32/64 fused multiply-add	7 years ago

Kito Cheng 896f51fbfa hardfloat: fix float32/64 fused multiply-add

Before falling back to softfloat FMA, we do not restore the original
values of inputs A and C. Fix it.

This bug was caught by running gcc's testsuite on RISC-V qemu.

Note that this change gives a small perf increase for fp-bench:

  Host: Intel(R) Core(TM) i7-4790K CPU @ 4.00GHz
  Command: perf stat -r 3 taskset -c 0 ./fp-bench -o mulAdd -p $prec

- $prec = single:
  - before:
    101.71 MFlops
    102.18 MFlops
    100.96 MFlops
  - after:
    103.63 MFlops
    103.05 MFlops
    102.96 MFlops

- $prec = double:
  - before:
    173.10 MFlops
    173.93 MFlops
    172.11 MFlops
  - after:
    178.49 MFlops
    178.88 MFlops
    178.66 MFlops

Signed-off-by: Kito Cheng <kito.cheng@gmail.com>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <20190322204320.17777-1-cota@braap.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

7 years ago

softfloat-specialize.h

target/mips: Fix minor bug in FPU

7 years ago

softfloat.c

hardfloat: fix float32/64 fused multiply-add

7 years ago