On 12/16/20 11:50 AM, Philippe Mathieu-Daudé wrote: > On 12/16/20 4:14 AM, Jiaxun Yang wrote: >> 在 2020/12/16 上午10:50, Jiaxun Yang 写道: >>> >>> >>> TBH I do think it doesn't sounds like a good idea to make 32-bit >>> and 64-bit different. In fact ISA_MIPS32R6 is always set for targets >>> with ISA_MIPS64R6. >>> >>> We're treating MIPS64R6 as a superset of MIPS32R6, and ISA_MIPS3 >>> is used to tell if a CPU supports 64-bit. I suppose you are talking about the CPU definitions (CPU_MIPS32R6/CPU_MIPS64R6). > > Which is why I don't understand why they are 2 ISA_MIPS32R6/ISA_MIPS64R6 > definitions. My comment is about the ISA definitions: #define ISA_MIPS32 0x0000000000000020ULL #define ISA_MIPS32R2 0x0000000000000040ULL #define ISA_MIPS64 0x0000000000000080ULL #define ISA_MIPS64R2 0x0000000000000100ULL #define ISA_MIPS32R3 0x0000000000000200ULL #define ISA_MIPS64R3 0x0000000000000400ULL #define ISA_MIPS32R5 0x0000000000000800ULL #define ISA_MIPS64R5 0x0000000000001000ULL #define ISA_MIPS32R6 0x0000000000002000ULL #define ISA_MIPS64R6 0x0000000000004000ULL > >>> >>> FYI: >>> https://commons.wikimedia.org/wiki/File:MIPS_instruction_set_family.svg >> >> Just add more cents here... >> The current method we handle R6 makes me a little bit annoying. >> >> Given that MIPS is backward compatible until R5, and R6 reorganized a lot >> of opcodes, I do think decoding procdure of R6 should be dedicated from >> the rest, >> otherwise we may fall into the hell of finding difference between R6 and >> previous >> ISAs, also I've heard some R6 only ASEs is occupying opcodes marked as >> "removed in R6", so it doesn't looks like a wise idea to check removed >> in R6 >> in helpers. > > I'm not sure I understood well your comment, but I also find how > R6 is handled messy... > > I'm doing this removal (from helper to decoder) with the decodetree > conversion. > >> So we may end up having four series of decodetrees for ISA >> Series1: MIPS-II, MIPS32, MIPS32R2, MIPS32R5 (32bit "old" ISAs) >> Series2: MIPS-III, MIPS64, MIPS64R2, MIPS64R5 (64bit "old" ISAs) >> >> Series3: MIPS32R6 (32bit "new" ISAs) >> Series4: MIPS64R6 (64bit "new" ISAs) > > Something like that, I'm starting by converting the messier leaves > first, so the R6 and ASEs. My approach is from your "series4" to > "series1" last. > > Regards, > > Phil. >
