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): /* 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) -- 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/
