(2014/05/20 0:04), Denys Vlasenko wrote: > On 05/17/2014 06:00 PM, Masami Hiramatsu wrote: >> (2014/05/17 3:34), Denys Vlasenko wrote: >>> Since xop and evex prefixes are extensions of vex mechanism, >>> they have similar bit layouts, and they can never be combined >>> (an instruction can have only one of them), >>> (ab)use insn->vex_prefix to store data of xop and evex too. >>> >>> Users will need to conditionalize on insn->vex_prefix.bytes[0] >>> instead of insn->vex_prefix.nbytes if they want to determine >>> which of vex(-like) prefixes are there. >>> >>> Instead of adding more inattr bits for these prefixes, drop >>> VEX inattr bits and use VEX opcode values directly to detect them. >>> There is no point in having additional level of indirection here. >>> (And we are close to running out of inattr bits for prefixes). >> >> Thank you very much for trying this work :) >> But sorry, Nak, I don't like to use the prefix byte directly. >> I'd rather like to add additional inattr bits for them. > > Ok, I'm looking at inat.h and looks like I need to widen > INAT_PFX_BITS, otherwise I have no space for two more bits > for two more prefixes (XOP and EVEX):
Yes, that's what I look forward! :) > > /* AVX VEX prefixes */ > #define INAT_PFX_VEX2 13 /* 2-bytes VEX prefix */ > #define INAT_PFX_VEX3 14 /* 3-bytes VEX prefix */ > ... > > /* Legacy prefix */ > #define INAT_PFX_OFFS 0 > #define INAT_PFX_BITS 4 > #define INAT_PFX_MAX ((1 << INAT_PFX_BITS) - 1) > #define INAT_PFX_MASK (INAT_PFX_MAX << INAT_PFX_OFFS) > > -- Masami HIRAMATSU Software Platform Research Dept. Linux Technology Research Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu...@hitachi.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
