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#include <caml/alloc.h>
#include <caml/memory.h>
#include <caml/mlvalues.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#ifdef _MSC_VER
#include <intrin.h>
#define __builtin_popcountll __popcnt64
#define __builtin_popcount __popcnt
static int __inline __builtin_clz(uint32_t x) {
int r = 0;
_BitScanReverse(&r, x);
return r;
}
static int __inline __builtin_clzll(uint64_t x) {
int r = 0;
#ifdef _WIN64
_BitScanReverse64(&r, x);
#else
if (!_BitScanReverse(&r, (uint32_t)x) &&
_BitScanReverse(&r, (uint32_t)(x >> 32))) {
r += 32;
}
#endif
return r;
}
static int __inline __builtin_ctz(uint32_t x) {
int r = 0;
_BitScanForward(&r, x);
return r;
}
static int __inline __builtin_ctzll(uint64_t x) {
int r = 0;
#ifdef _WIN64
_BitScanForward64(&r, x);
#else
if (_BitScanForward(&r, (uint32_t)(x >> 32))) {
r += 32;
} else {
_BitScanForward(&r, (uint32_t)x);
}
#endif
return r;
}
#endif
static int64_t int_pow(int64_t base, int64_t exponent) {
int64_t ret = 1;
int64_t mul[4];
mul[0] = 1;
mul[1] = base;
mul[3] = 1;
while (exponent != 0) {
mul[1] *= mul[3];
mul[2] = mul[1] * mul[1];
mul[3] = mul[2] * mul[1];
ret *= mul[exponent & 3];
exponent >>= 2;
}
return ret;
}
CAMLprim value Base_int_math_int_pow_stub(value base, value exponent) {
return (Val_long(int_pow(Long_val(base), Long_val(exponent))));
}
CAMLprim value Base_int_math_int64_pow_stub(value base, value exponent) {
CAMLparam2(base, exponent);
CAMLreturn(caml_copy_int64(int_pow(Int64_val(base), Int64_val(exponent))));
}
/* This implementation is faster than [__builtin_popcount(v) - 1], even though
* it seems more complicated. The [&] clears the shifted sign bit after
* [Long_val] or [Int_val]. */
CAMLprim value Base_int_math_int_popcount(value v) {
#ifdef ARCH_SIXTYFOUR
return Val_int(__builtin_popcountll(Long_val(v) & ~((uint64_t)1 << 63)));
#else
return Val_int(__builtin_popcount(Int_val(v) & ~((uint32_t)1 << 31)));
#endif
}
/* The specification of all below [clz] and [ctz] functions are undefined for [v
* = 0]. */
/*
* For an int [x] in the [2n + 1] representation:
*
* clz(x) = __builtin_clz(x >> 1) - 1
*
* If [x] is negative, then the macro [Int_val] would perform a arithmetic
* shift right, rather than a logical shift right, and sign extend the number.
* Therefore
*
* __builtin_clz(Int_val(x))
*
* would always be zero, so
*
* clz(x) = __builtin_clz(Int_val(x)) - 1
*
* would always be -1. This is not what we want.
*
* The logical shift right adds a leading zero to the argument of
* __builtin_clz, which the -1 accounts for. Rather than adding the leading
* zero and subtracting, we can just compute the clz of the tagged
* representation, and that should be equivalent, while also handing negative
* inputs correctly (the result will now be 0).
*/
intnat Base_int_math_int_clz_untagged(value v) {
#ifdef ARCH_SIXTYFOUR
return __builtin_clzll(v);
#else
return __builtin_clz(v);
#endif
}
CAMLprim value Base_int_math_int_clz(value v) {
return Val_int(Base_int_math_int_clz_untagged(v));
}
intnat Base_int_math_int32_clz_unboxed(int32_t v) { return __builtin_clz(v); }
CAMLprim value Base_int_math_int32_clz(value v) {
return Val_int(Base_int_math_int32_clz_unboxed(Int32_val(v)));
}
intnat Base_int_math_int64_clz_unboxed(int64_t v) { return __builtin_clzll(v); }
CAMLprim value Base_int_math_int64_clz(value v) {
return Val_int(Base_int_math_int64_clz_unboxed(Int64_val(v)));
}
intnat Base_int_math_nativeint_clz_unboxed(intnat v) {
#ifdef ARCH_SIXTYFOUR
return __builtin_clzll(v);
#else
return __builtin_clz(v);
#endif
}
CAMLprim value Base_int_math_nativeint_clz(value v) {
return Val_int(Base_int_math_nativeint_clz_unboxed(Nativeint_val(v)));
}
intnat Base_int_math_int_ctz_untagged(intnat v) {
#ifdef ARCH_SIXTYFOUR
return __builtin_ctzll(v);
#else
return __builtin_ctz(v);
#endif
}
CAMLprim value Base_int_math_int_ctz(value v) {
return Val_int(Base_int_math_int_ctz_untagged(Int_val(v)));
}
intnat Base_int_math_int32_ctz_unboxed(int32_t v) { return __builtin_ctz(v); }
CAMLprim value Base_int_math_int32_ctz(value v) {
return Val_int(Base_int_math_int32_ctz_unboxed(Int32_val(v)));
}
intnat Base_int_math_int64_ctz_unboxed(int64_t v) { return __builtin_ctzll(v); }
CAMLprim value Base_int_math_int64_ctz(value v) {
return Val_int(Base_int_math_int64_ctz_unboxed(Int64_val(v)));
}
intnat Base_int_math_nativeint_ctz_unboxed(intnat v) {
#ifdef ARCH_SIXTYFOUR
return __builtin_ctzll(v);
#else
return __builtin_ctz(v);
#endif
}
CAMLprim value Base_int_math_nativeint_ctz(value v) {
return Val_int(Base_int_math_nativeint_ctz_unboxed(Nativeint_val(v)));
}
CAMLprim value __attribute__((weak))
caml_csel_value(value v_cond, value v_true, value v_false) {
return (Bool_val(v_cond) ? v_true : v_false);
}
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