On Tue, Jan 29, 2019 at 3:04 PM Peter Maydell <peter.mayd...@linaro.org> wrote: > > In disas_simd_indexed(), for the case of "complex fp", each indexable > element is a complex pair, so the total size is twice that indicated > in the 'size' field in the encoding. We were trying to do this > "double the size" operation with a left shift by 1, but this is > incorrect because the 'size' field is a MO_8/MO_16/MO_32/MO_64 > value, and doubling the size should be done by a simple increment. > > This meant we were mishandling FCMLA (by element) of values where > the real and imaginary parts are 32-bit floats, and would incorrectly > UNDEF this encoding. (No other insns take this code path, and for > 16-bit floats it happens that 1 << 1 and 1 + 1 are both the same). > > Reported-by: Laurent Desnogues <laurent.desnog...@gmail.com> > Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
Reviewed-by: Laurent Desnogues <laurent.desnog...@gmail.com> Thanks, Laurent > --- > target/arm/translate-a64.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/target/arm/translate-a64.c b/target/arm/translate-a64.c > index a7b999d2b5a..06418f0ac3c 100644 > --- a/target/arm/translate-a64.c > +++ b/target/arm/translate-a64.c > @@ -12680,7 +12680,7 @@ static void disas_simd_indexed(DisasContext *s, > uint32_t insn) > > case 2: /* complex fp */ > /* Each indexable element is a complex pair. */ > - size <<= 1; > + size += 1; > switch (size) { > case MO_32: > if (h && !is_q) { > -- > 2.20.1 >