(2014/05/17 3:34), Denys Vlasenko wrote:
> Before this patch, users need to do this to fetch vex.vvvv:
>
> if (insn->vex_prefix.nbytes == 2) {
> vex_vvvv = ((insn->vex_prefix.bytes[1] >> 3) & 0xf) ^ 0xf;
> }
> if (insn->vex_prefix.nbytes == 3) {
> vex_vvvv = ((insn->vex_prefix.bytes[2] >> 3) & 0xf) ^ 0xf;
> }
>
> Make it so that insn->vex_prefix.bytes[2] always contains vex.wvvvvLpp bits.
I like this hack :)
If you don't mind, please add inline functions to get such vex bits from
struct insn too?
Thank you,
>
> Signed-off-by: Denys Vlasenko <[email protected]>
> Cc: Masami Hiramatsu <[email protected]>
> Cc: Frank Ch. Eigler <[email protected]>
> Cc: Srikar Dronamraju <[email protected]>
> Cc: Ananth N Mavinakayanahalli <[email protected]>
> Cc: Jim Keniston <[email protected]>
> Cc: Oleg Nesterov <[email protected]>
> Cc: Andi Kleen <[email protected]>
> Cc: Ingo Molnar <[email protected]>
> ---
> arch/x86/lib/insn.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
> index 54fcffe..829ca4c 100644
> --- a/arch/x86/lib/insn.c
> +++ b/arch/x86/lib/insn.c
> @@ -163,6 +163,12 @@ found:
> /* VEX.W overrides opnd_size */
> insn->opnd_bytes = 8;
> } else {
> + /*
> + * For VEX2, fake VEX3-like byte#2.
> + * Makes it easier to decode vex.W, vex.vvvv,
> + * vex.L and vex.pp. Masking with 0x7f sets vex.W == 0.
> + */
> + insn->vex_prefix.bytes[2] = b2 & 0x7f;
> insn->vex_prefix.nbytes = 2;
> insn->next_byte += 2;
> }
>
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Research Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: [email protected]
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