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target-arm: fix VSHLL Neon instruction. 

Fix bit mask used when widening the result of shift on narrow input.

Signed-off-by: Christophe Lyon <christophe.lyon@st.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
This commit is contained in:
Christophe Lyon 2011-02-09 13:19:15 +01:00 committed by Aurelien Jarno
parent efd410373a
commit acdf01effa
1 changed files with 15 additions and 3 deletions
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18
target-arm/translate.c
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@ -4880,16 +4880,28 @@ static int disas_neon_data_insn(CPUState * env, DisasContext *s, uint32_t insn)
/* The shift is less than the width of the source /* The shift is less than the width of the source
type, so we can just shift the whole register. */ type, so we can just shift the whole register. */
tcg_gen_shli_i64(cpu_V0, cpu_V0, shift); 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) { if (size < 2 || !u) {
uint64_t imm64; uint64_t imm64;
if (size == 0) { if (size == 0) {
imm = (0xffu >> (8 - shift)); imm = (0xffu >> (8 - shift));
imm |= imm << 16; imm |= imm << 16;
} else { } else if (size == 1) {
imm = 0xffff >> (16 - shift); imm = 0xffff >> (16 - shift);
} else {
/* size == 2 */
imm = 0xffffffff >> (32 - shift);
} }
imm64 = imm | (((uint64_t)imm) << 32); if (size < 2) {
tcg_gen_andi_i64(cpu_V0, cpu_V0, imm64); imm64 = imm | (((uint64_t)imm) << 32);
} else {
imm64 = imm;
}
tcg_gen_andi_i64(cpu_V0, cpu_V0, ~imm64);
} }
} }
neon_store_reg64(cpu_V0, rd + pass); neon_store_reg64(cpu_V0, rd + pass);