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Use GCC 4 compiler builtins for XORs

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git-svn-id: file://localhost/svn/verilator/trunk/verilator@1033 77ca24e4-aefa-0310-84f0-b9a241c72d87
This commit is contained in:
Wilson Snyder 2008-04-24 14:26:01 +00:00
parent 956a0a9c99
commit 215bdfccc2
1 changed files with 27 additions and 10 deletions
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37
include/verilated.h
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@ -460,39 +460,55 @@ static inline IData VL_REDOR_W(int words, WDataInP lwp) {
}
// EMIT_RULE: VL_REDXOR: oclean=dirty; obits=1;
static inline IData VL_REDXOR_W(int words, WDataInP lwp) {
IData r = lwp[0];
for (int i=1; i < words; i++) r ^= lwp[i];
r=(r^(r>>1));
r=(r^(r>>2));
r=(r^(r>>4));
r=(r^(r>>8));
r=(r^(r>>16));
return r;
}
static inline IData VL_REDXOR_2(IData r) {
// Experiments show VL_REDXOR_2 is faster than __builtin_parityl
r=(r^(r>>1));
return r;
}
static inline IData VL_REDXOR_4(IData r) {
#if defined(__GNUC__) && (__GNUC__ >= 4) && !defined(VL_NO_BUILTINS)
return __builtin_parityl(r);
#else
r=(r^(r>>1)); r=(r^(r>>2));
return r;
#endif
}
static inline IData VL_REDXOR_8(IData r) {
#if defined(__GNUC__) && (__GNUC__ >= 4) && !defined(VL_NO_BUILTINS)
return __builtin_parityl(r);
#else
r=(r^(r>>1)); r=(r^(r>>2)); r=(r^(r>>4));
return r;
#endif
}
static inline IData VL_REDXOR_16(IData r) {
#if defined(__GNUC__) && (__GNUC__ >= 4) && !defined(VL_NO_BUILTINS)
return __builtin_parityl(r);
#else
r=(r^(r>>1)); r=(r^(r>>2)); r=(r^(r>>4)); r=(r^(r>>8));
return r;
#endif
}
static inline IData VL_REDXOR_32(IData r) {
#if defined(__GNUC__) && (__GNUC__ >= 4) && !defined(VL_NO_BUILTINS)
return __builtin_parityl(r);
#else
r=(r^(r>>1)); r=(r^(r>>2)); r=(r^(r>>4)); r=(r^(r>>8)); r=(r^(r>>16));
return r;
#endif
}
static inline IData VL_REDXOR_64(QData r) {
#if defined(__GNUC__) && (__GNUC__ >= 4) && !defined(VL_NO_BUILTINS)
return __builtin_parityll(r);
#else
r=(r^(r>>1)); r=(r^(r>>2)); r=(r^(r>>4)); r=(r^(r>>8)); r=(r^(r>>16)); r=(r^(r>>32));
return r;
#endif
}
static inline IData VL_REDXOR_W(int words, WDataInP lwp) {
IData r = lwp[0];
for (int i=1; i < words; i++) r ^= lwp[i];
return VL_REDXOR_32(r);
}
static inline IData VL_CLOG2_I(IData lhs) {
@ -529,6 +545,7 @@ static inline IData VL_CLOG2_W(int words, WDataInP lwp) {
// EMIT_RULE: VL_COUNTONES_II: oclean = false; lhs clean
static inline IData VL_COUNTONES_I(IData lhs) {
// This is faster than __builtin_popcountl
IData r = lhs - ((lhs >> 1) & 033333333333) - ((lhs >> 2) & 011111111111);
r = (r + (r>>3)) & 030707070707;
r = (r + (r>>6));