Commit d88a0f65 authored by Paul Eggert's avatar Paul Eggert

Simplify logcount implementation

* src/data.c (HAVE_BUILTIN_POPCOUNTLL, logcount32, logcount64):
Remove.
(Flogcount): Simplify by using count_one_bits.
parent 185f3334
......@@ -3069,64 +3069,18 @@ usage: (logxor &rest INTS-OR-MARKERS) */)
return arith_driver (Alogxor, nargs, args);
}
#if GNUC_PREREQ (4, 1, 0)
#define HAVE_BUILTIN_POPCOUNTLL
#endif
#ifndef HAVE_BUILTIN_POPCOUNTLL
static uint32_t
logcount32 (uint32_t b)
{
b -= (b >> 1) & 0x55555555;
b = (b & 0x33333333) + ((b >> 2) & 0x33333333);
b = (b + (b >> 4)) & 0x0f0f0f0f;
return (b * 0x01010101) >> 24;
}
static uint64_t
logcount64 (uint64_t b)
{
b -= (b >> 1) & 0x5555555555555555ULL;
b = (b & 0x3333333333333333ULL) + ((b >> 2) & 0x3333333333333333ULL);
b = (b + (b >> 4)) & 0x0f0f0f0f0f0f0f0fULL;
return (b * 0x0101010101010101ULL) >> 56;
}
#endif /* HAVE_BUILTIN_POPCOUNTLL */
DEFUN ("logcount", Flogcount, Slogcount, 1, 1, 0,
doc: /* Return population count of VALUE.
If VALUE is negative, the count is of its two's complement representation. */)
(register Lisp_Object value)
(Lisp_Object value)
{
Lisp_Object res;
EMACS_UINT v;
CHECK_NUMBER (value);
v = XUINT (value);
#ifdef HAVE_BUILTIN_POPCOUNTLL
if (v <= UINT_MAX)
XSETINT (res, __builtin_popcount (v));
else if (v <= ULONG_MAX)
XSETINT (res, __builtin_popcountl (v));
else if (v <= ULONG_LONG_MAX)
XSETINT (res, __builtin_popcountll (v));
#else /* HAVE_BUILTIN_POPCOUNTLL */
if (v <= UINT_MAX)
XSETINT (res, logcount32 (v));
else if (v <= ULONG_MAX || v <= ULONG_LONG_MAX)
XSETINT (res, logcount64 (v));
#endif /* HAVE_BUILTIN_POPCOUNTLL */
else
{
unsigned int count;
for (count = 0; v; count++)
{
v &= v - 1;
}
XSETINT (res, count);
}
return res;
EMACS_UINT v = XUINT (value);
return make_number (EMACS_UINT_WIDTH <= UINT_WIDTH
? count_one_bits (v)
: EMACS_UINT_WIDTH <= ULONG_WIDTH
? count_one_bits_l (v)
: count_one_bits_ll (v));
}
static Lisp_Object
......
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