Commit fc8135a4 authored by Peter Maydell's avatar Peter Maydell
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Merge remote-tracking branch 'remotes/rth/tags/pull-axp-20150902' into staging 



cmpbge emulation improvements

# gpg: Signature made Wed 02 Sep 2015 20:25:10 BST using RSA key ID 4DD0279B
# gpg: Good signature from "Richard Henderson <rth7680@gmail.com>"
# gpg:                 aka "Richard Henderson <rth@redhat.com>"
# gpg:                 aka "Richard Henderson <rth@twiddle.net>"

* remotes/rth/tags/pull-axp-20150902:
  target-alpha: Special case cmpbge with zero
  target-alpha: Rewrite helper_cmpbge using bit tests

Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
parents 654cd2c5 112e4518

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

+39 −12
Original line number Diff line number Diff line
@@ -58,20 +58,47 @@ uint64_t helper_zap(uint64_t val, uint64_t mask) 
    return helper_zapnot(val, ~mask);

}



uint64_t helper_cmpbge(uint64_t op1, uint64_t op2)

uint64_t helper_cmpbe0(uint64_t a)

{

    uint8_t opa, opb, res;

    int i;



    res = 0;

    for (i = 0; i < 8; i++) {

        opa = op1 >> (i * 8);

        opb = op2 >> (i * 8);

        if (opa >= opb) {

            res |= 1 << i;

        }

    }

    return res;

    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;

    uint64_t test = 0x0100010001000100ULL;

    uint64_t al, ah, bl, bh, cl, ch;



    /* Separate the bytes to avoid false positives.  */

    al = a & mask;

    bl = b & mask;

    ah = (a >> 8) & mask;

    bh = (b >> 8) & mask;



    /* "Compare".  If a byte in B is greater than a byte in A,

       it will clear the test bit.  */

    cl = ((al | test) - bl) & test;

    ch = ((ah | test) - bh) & test;



    /* Fold all of the test bits into a contiguous set.  */

    /* ch=.......a...............c...............e...............g........ */

    /* cl=.......b...............d...............f...............h........ */

    cl += ch << 1;

    /* cl=......ab..............cd..............ef..............gh........ */

    cl |= cl << 14;

    /* cl=......abcd............cdef............efgh............gh........ */

    cl |= cl << 28;

    /* cl=......abcdefgh........cdefgh..........efgh............gh........ */

    return cl >> 50;

}



uint64_t helper_minub8(uint64_t op1, uint64_t op2)

target-alpha/translate.c

+6 −1
Original line number Diff line number Diff line
@@ -1562,7 +1562,12 @@ 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 */