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py/misc: Add a popcount(uint32_t) implementation.

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This makes the existing popcount(uint32_t) implementation found in the
RV32 emitter available to the rest of the codebase.  This version of
popcount will use intrinsic or builtin implementations if they are
available, falling back to a generic implementation if that is not the
case.

Signed-off-by: Alessandro Gatti <a.gatti@frob.it>
This commit is contained in:
Alessandro Gatti
2024-08-22 00:48:55 +02:00
parent a5270c84cf
commit 3044233ea3
2 changed files with 19 additions and 22 deletions
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17
py/misc.h
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@@ -370,12 +370,29 @@ static inline uint32_t mp_ctz(uint32_t x) {
static inline bool mp_check(bool value) {
return value;
}
static inline uint32_t mp_popcount(uint32_t x) {
return __popcnt(x);
}
#else
#define mp_clz(x) __builtin_clz(x)
#define mp_clzl(x) __builtin_clzl(x)
#define mp_clzll(x) __builtin_clzll(x)
#define mp_ctz(x) __builtin_ctz(x)
#define mp_check(x) (x)
#if defined __has_builtin
#if __has_builtin(__builtin_popcount)
#define mp_popcount(x) __builtin_popcount(x)
#endif
#endif
#if !defined(mp_popcount)
static inline uint32_t mp_popcount(uint32_t x) {
x = x - ((x >> 1) & 0x55555555);
x = (x & 0x33333333) + ((x >> 2) & 0x33333333);
x = (x + (x >> 4)) & 0x0F0F0F0F;
return x * 0x01010101;
}
#endif
#endif
// mp_int_t can be larger than long, i.e. Windows 64-bit, nan-box variants