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target-i386: Use clz/ctz for bsf/bsr helpers 

And mark the helpers as NO_RWG_SE.

Signed-off-by: Richard Henderson <rth@twiddle.net>
This commit is contained in:
Richard Henderson 2013-01-21 11:52:26 -08:00
parent cd7f97cafd
commit f1300734cb
2 changed files with 14 additions and 37 deletions
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6
target-i386/helper.h
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@ -195,9 +195,9 @@ DEF_HELPER_3(frstor, void, env, tl, int)
DEF_HELPER_3(fxsave, void, env, tl, int) DEF_HELPER_3(fxsave, void, env, tl, int)
DEF_HELPER_3(fxrstor, void, env, tl, int) DEF_HELPER_3(fxrstor, void, env, tl, int)
DEF_HELPER_1(bsf, tl, tl) DEF_HELPER_FLAGS_1(bsf, TCG_CALL_NO_RWG_SE, tl, tl)
DEF_HELPER_1(bsr, tl, tl) DEF_HELPER_FLAGS_1(bsr, TCG_CALL_NO_RWG_SE, tl, tl)
DEF_HELPER_2(lzcnt, tl, tl, int) DEF_HELPER_FLAGS_2(lzcnt, TCG_CALL_NO_RWG_SE, tl, tl, int)
DEF_HELPER_FLAGS_2(pdep, TCG_CALL_NO_RWG_SE, tl, tl, tl) DEF_HELPER_FLAGS_2(pdep, TCG_CALL_NO_RWG_SE, tl, tl, tl)
DEF_HELPER_FLAGS_2(pext, TCG_CALL_NO_RWG_SE, tl, tl, tl) DEF_HELPER_FLAGS_2(pext, TCG_CALL_NO_RWG_SE, tl, tl, tl)

45
target-i386/int_helper.c
View File

@ -447,53 +447,30 @@ void helper_idivq_EAX(CPUX86State *env, target_ulong t0)
} }
#endif #endif
#if TARGET_LONG_BITS == 32
# define ctztl ctz32
# define clztl clz32
#else
# define ctztl ctz64
# define clztl clz64
#endif
/* bit operations */ /* bit operations */
target_ulong helper_bsf(target_ulong t0) target_ulong helper_bsf(target_ulong t0)
{ {
int count; return ctztl(t0);
target_ulong res;
res = t0;
count = 0;
while ((res & 1) == 0) {
count++;
res >>= 1;
}
return count;
} }
target_ulong helper_lzcnt(target_ulong t0, int wordsize) target_ulong helper_lzcnt(target_ulong t0, int wordsize)
{ {
int count; return clztl(t0) - (TARGET_LONG_BITS - wordsize);
target_ulong res, mask;
if (wordsize > 0 && t0 == 0) {
return wordsize;
}
res = t0;
count = TARGET_LONG_BITS - 1;
mask = (target_ulong)1 << (TARGET_LONG_BITS - 1);
while ((res & mask) == 0) {
count--;
res <<= 1;
}
if (wordsize > 0) {
return wordsize - 1 - count;
}
return count;
} }
target_ulong helper_bsr(target_ulong t0) target_ulong helper_bsr(target_ulong t0)
{ {
return helper_lzcnt(t0, 0); return clztl(t0) ^ (TARGET_LONG_BITS - 1);
} }
#if TARGET_LONG_BITS == 32
# define ctztl ctz32
#else
# define ctztl ctz64
#endif
target_ulong helper_pdep(target_ulong src, target_ulong mask) target_ulong helper_pdep(target_ulong src, target_ulong mask)
{ {
target_ulong dest = 0; target_ulong dest = 0;