| Message ID | 4D528643.4080106@st.com |
|---|---|
| State | New |
| Headers | show |
On 9 February 2011 12:19, Christophe Lyon <christophe.lyon@st.com> wrote: > > Fix bit mask used when widening the result of shift on narrow input. > > Signed-off-by: Christophe Lyon <christophe.lyon@st.com> Confirmed with random instruction testing that this patch fixes VSHLL. Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
On Wed, Feb 09, 2011 at 02:23:24PM +0000, Peter Maydell wrote: > On 9 February 2011 12:19, Christophe Lyon <christophe.lyon@st.com> wrote: > > > > Fix bit mask used when widening the result of shift on narrow input. > > > > Signed-off-by: Christophe Lyon <christophe.lyon@st.com> > > Confirmed with random instruction testing that this patch fixes VSHLL. > > Reviewed-by: Peter Maydell <peter.maydell@linaro.org> > Thanks, applied.
diff --git a/target-arm/translate.c b/target-arm/translate.c index b694eed..16c61f1 100644 --- a/target-arm/translate.c +++ b/target-arm/translate.c @@ -4882,16 +4882,28 @@ static int disas_neon_data_insn(CPUState * env, DisasContext *s, uint32_t insn) /* The shift is less than the width of the source type, so we can just shift the whole register. */ tcg_gen_shli_i64(cpu_V0, cpu_V0, shift); + /* Widen the result of shift: we need to clear + * the potential overflow bits resulting from + * left bits of the narrow input appearing as + * right bits of left the neighbour narrow + * input. */ if (size < 2 || !u) { uint64_t imm64; if (size == 0) { imm = (0xffu >> (8 - shift)); imm |= imm << 16; - } else { + } else if (size == 1) { imm = 0xffff >> (16 - shift); + } else { + /* size == 2 */ + imm = 0xffffffff >> (32 - shift); + } + if (size < 2) { + imm64 = imm | (((uint64_t)imm) << 32); + } else { + imm64 = imm; } - imm64 = imm | (((uint64_t)imm) << 32); - tcg_gen_andi_i64(cpu_V0, cpu_V0, imm64); + tcg_gen_andi_i64(cpu_V0, cpu_V0, ~imm64); } } neon_store_reg64(cpu_V0, rd + pass);
Fix bit mask used when widening the result of shift on narrow input. Signed-off-by: Christophe Lyon <christophe.lyon@st.com> --- target-arm/translate.c | 18 +++++++++++++++--- 1 files changed, 15 insertions(+), 3 deletions(-)