Commit 112e4518 authored by Richard Henderson's avatar Richard Henderson
Browse files

target-alpha: Special case cmpbge with zero 



Knowing the comparator is zero leads to a simpler operation.

Signed-off-by: default avatarRichard Henderson <rth@twiddle.net>
parent 5f2a80ad

target-alpha/helper.h

+1 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ DEF_HELPER_FLAGS_1(cttz, TCG_CALL_NO_RWG_SE, i64, i64) 
DEF_HELPER_FLAGS_2(zap, TCG_CALL_NO_RWG_SE, i64, i64, i64)

DEF_HELPER_FLAGS_2(zapnot, TCG_CALL_NO_RWG_SE, i64, i64, i64)



DEF_HELPER_FLAGS_1(cmpbe0, TCG_CALL_NO_RWG_SE, i64, i64)

DEF_HELPER_FLAGS_2(cmpbge, TCG_CALL_NO_RWG_SE, i64, i64, i64)



DEF_HELPER_FLAGS_2(minub8, TCG_CALL_NO_RWG_SE, i64, i64, i64)

target-alpha/int_helper.c

+14 −0
Original line number Diff line number Diff line
@@ -58,6 +58,20 @@ uint64_t helper_zap(uint64_t val, uint64_t mask) 
    return helper_zapnot(val, ~mask);

}



uint64_t helper_cmpbe0(uint64_t a)

{

    uint64_t m = 0x7f7f7f7f7f7f7f7fULL;

    uint64_t c = ~(((a & m) + m) | a | m);

    /* a.......b.......c.......d.......e.......f.......g.......h....... */

    c |= c << 7;

    /* ab......bc......cd......de......ef......fg......gh......h....... */

    c |= c << 14;

    /* abcd....bcde....cdef....defg....efgh....fgh.....gh......h....... */

    c |= c << 28;

    /* abcdefghbcdefgh.cdefgh..defgh...efgh....fgh.....gh......h....... */

    return c >> 56;

}



uint64_t helper_cmpbge(uint64_t a, uint64_t b)

{

    uint64_t mask = 0x00ff00ff00ff00ffULL;

target-alpha/translate.c

+6 −1
Original line number Diff line number Diff line
@@ -1507,7 +1507,12 @@ static ExitStatus translate_one(DisasContext *ctx, uint32_t insn) 
            break;

        case 0x0F:

            /* CMPBGE */

            if (ra == 31) {

                /* Special case 0 >= X as X == 0.  */

                gen_helper_cmpbe0(vc, vb);

            } else {

                gen_helper_cmpbge(vc, va, vb);

            }

            break;

        case 0x12:

            /* S8ADDL */