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#pragma once
#ifndef FXDIV_H
#define FXDIV_H
#if defined(__cplusplus) && (__cplusplus >= 201103L)
#include <cstddef>
#include <cstdint>
#include <climits>
#elif !defined(__OPENCL_VERSION__)
#include <stddef.h>
#include <stdint.h>
#include <limits.h>
#endif
#if defined(_MSC_VER)
#include <intrin.h>
#if defined(_M_IX86) || defined(_M_X64)
#include <immintrin.h>
#endif
#endif
#ifndef FXDIV_USE_INLINE_ASSEMBLY
#define FXDIV_USE_INLINE_ASSEMBLY 0
#endif
static inline uint64_t fxdiv_mulext_uint32_t(uint32_t a, uint32_t b) {
#if defined(_MSC_VER) && defined(_M_IX86)
return (uint64_t) __emulu((unsigned int) a, (unsigned int) b);
#else
return (uint64_t) a * (uint64_t) b;
#endif
}
static inline uint32_t fxdiv_mulhi_uint32_t(uint32_t a, uint32_t b) {
#if defined(__OPENCL_VERSION__)
return mul_hi(a, b);
#elif defined(__CUDA_ARCH__)
return (uint32_t) __umulhi((unsigned int) a, (unsigned int) b);
#elif defined(_MSC_VER) && defined(_M_IX86)
return (uint32_t) (__emulu((unsigned int) a, (unsigned int) b) >> 32);
#elif defined(_MSC_VER) && defined(_M_ARM)
return (uint32_t) _MulUnsignedHigh((unsigned long) a, (unsigned long) b);
#else
return (uint32_t) (((uint64_t) a * (uint64_t) b) >> 32);
#endif
}
static inline uint64_t fxdiv_mulhi_uint64_t(uint64_t a, uint64_t b) {
#if defined(__OPENCL_VERSION__)
return mul_hi(a, b);
#elif defined(__CUDA_ARCH__)
return (uint64_t) __umul64hi((unsigned long long) a, (unsigned long long) b);
#elif defined(_MSC_VER) && defined(_M_X64)
return (uint64_t) __umulh((unsigned __int64) a, (unsigned __int64) b);
#elif defined(__GNUC__) && defined(__SIZEOF_INT128__)
return (uint64_t) (((((unsigned __int128) a) * ((unsigned __int128) b))) >> 64);
#else
const uint32_t a_lo = (uint32_t) a;
const uint32_t a_hi = (uint32_t) (a >> 32);
const uint32_t b_lo = (uint32_t) b;
const uint32_t b_hi = (uint32_t) (b >> 32);
const uint64_t t = fxdiv_mulext_uint32_t(a_hi, b_lo) +
(uint64_t) fxdiv_mulhi_uint32_t(a_lo, b_lo);
return fxdiv_mulext_uint32_t(a_hi, b_hi) + (t >> 32) +
((fxdiv_mulext_uint32_t(a_lo, b_hi) + (uint64_t) (uint32_t) t) >> 32);
#endif
}
static inline size_t fxdiv_mulhi_size_t(size_t a, size_t b) {
#if SIZE_MAX == UINT32_MAX
return (size_t) fxdiv_mulhi_uint32_t((uint32_t) a, (uint32_t) b);
#elif SIZE_MAX == UINT64_MAX
return (size_t) fxdiv_mulhi_uint64_t((uint64_t) a, (uint64_t) b);
#else
#error Unsupported platform
#endif
}
struct fxdiv_divisor_uint32_t {
uint32_t value;
uint32_t m;
uint8_t s1;
uint8_t s2;
};
struct fxdiv_result_uint32_t {
uint32_t quotient;
uint32_t remainder;
};
struct fxdiv_divisor_uint64_t {
uint64_t value;
uint64_t m;
uint8_t s1;
uint8_t s2;
};
struct fxdiv_result_uint64_t {
uint64_t quotient;
uint64_t remainder;
};
struct fxdiv_divisor_size_t {
size_t value;
size_t m;
uint8_t s1;
uint8_t s2;
};
struct fxdiv_result_size_t {
size_t quotient;
size_t remainder;
};
static inline struct fxdiv_divisor_uint32_t fxdiv_init_uint32_t(uint32_t d) {
struct fxdiv_divisor_uint32_t result = { d };
if (d == 1) {
result.m = UINT32_C(1);
result.s1 = 0;
result.s2 = 0;
} else {
#if defined(__OPENCL_VERSION__)
const uint32_t l_minus_1 = 31 - clz(d - 1);
#elif defined(__CUDA_ARCH__)
const uint32_t l_minus_1 = 31 - __clz((int) (d - 1));
#elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64) || defined(_M_ARM) || defined(_M_ARM64))
unsigned long l_minus_1;
_BitScanReverse(&l_minus_1, (unsigned long) (d - 1));
#elif defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)) && FXDIV_USE_INLINE_ASSEMBLY
uint32_t l_minus_1;
__asm__("BSRL %[d_minus_1], %[l_minus_1]"
: [l_minus_1] "=r" (l_minus_1)
: [d_minus_1] "r" (d - 1)
: "cc");
#elif defined(__GNUC__)
const uint32_t l_minus_1 = 31 - __builtin_clz(d - 1);
#else
/* Based on Algorithm 2 from Hacker's delight */
uint32_t l_minus_1 = 0;
uint32_t x = d - 1;
uint32_t y = x >> 16;
if (y != 0) {
l_minus_1 += 16;
x = y;
}
y = x >> 8;
if (y != 0) {
l_minus_1 += 8;
x = y;
}
y = x >> 4;
if (y != 0) {
l_minus_1 += 4;
x = y;
}
y = x >> 2;
if (y != 0) {
l_minus_1 += 2;
x = y;
}
if ((x & 2) != 0) {
l_minus_1 += 1;
}
#endif
uint32_t u_hi = (UINT32_C(2) << (uint32_t) l_minus_1) - d;
/* Division of 64-bit number u_hi:UINT32_C(0) by 32-bit number d, 32-bit quotient output q */
#if defined(__GNUC__) && defined(__i386__) && FXDIV_USE_INLINE_ASSEMBLY
uint32_t q;
__asm__("DIVL %[d]"
: "=a" (q), "+d" (u_hi)
: [d] "r" (d), "a" (0)
: "cc");
#elif (defined(_MSC_VER) && _MSC_VER >= 1920) && !defined(__clang__) && !defined(__INTEL_COMPILER) && (defined(_M_IX86) || defined(_M_X64))
unsigned int remainder;
const uint32_t q = (uint32_t) _udiv64((unsigned __int64) ((uint64_t) u_hi << 32), (unsigned int) d, &remainder);
#else
const uint32_t q = ((uint64_t) u_hi << 32) / d;
#endif
result.m = q + UINT32_C(1);
result.s1 = 1;
result.s2 = (uint8_t) l_minus_1;
}
return result;
}
static inline struct fxdiv_divisor_uint64_t fxdiv_init_uint64_t(uint64_t d) {
struct fxdiv_divisor_uint64_t result = { d };
if (d == 1) {
result.m = UINT64_C(1);
result.s1 = 0;
result.s2 = 0;
} else {
#if defined(__OPENCL_VERSION__)
const uint32_t nlz_d = clz(d);
const uint32_t l_minus_1 = 63 - clz(d - 1);
#elif defined(__CUDA_ARCH__)
const uint32_t nlz_d = __clzll((long long) d);
const uint32_t l_minus_1 = 63 - __clzll((long long) (d - 1));
#elif defined(_MSC_VER) && (defined(_M_X64) || defined(_M_ARM64))
unsigned long l_minus_1;
_BitScanReverse64(&l_minus_1, (unsigned __int64) (d - 1));
unsigned long bsr_d;
_BitScanReverse64(&bsr_d, (unsigned __int64) d);
const uint32_t nlz_d = bsr_d ^ 0x3F;
#elif defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_ARM))
const uint64_t d_minus_1 = d - 1;
const uint8_t d_is_power_of_2 = (d & d_minus_1) == 0;
unsigned long l_minus_1;
if ((uint32_t) (d_minus_1 >> 32) == 0) {
_BitScanReverse(&l_minus_1, (unsigned long) d_minus_1);
} else {
_BitScanReverse(&l_minus_1, (unsigned long) (uint32_t) (d_minus_1 >> 32));
l_minus_1 += 32;
}
const uint32_t nlz_d = ((uint8_t) l_minus_1 ^ UINT8_C(0x3F)) - d_is_power_of_2;
#elif defined(__GNUC__) && defined(__x86_64__) && FXDIV_USE_INLINE_ASSEMBLY
uint64_t l_minus_1;
__asm__("BSRQ %[d_minus_1], %[l_minus_1]"
: [l_minus_1] "=r" (l_minus_1)
: [d_minus_1] "r" (d - 1)
: "cc");
#elif defined(__GNUC__)
const uint32_t l_minus_1 = 63 - __builtin_clzll(d - 1);
const uint32_t nlz_d = __builtin_clzll(d);
#else
/* Based on Algorithm 2 from Hacker's delight */
const uint64_t d_minus_1 = d - 1;
const uint32_t d_is_power_of_2 = (d & d_minus_1) == 0;
uint32_t l_minus_1 = 0;
uint32_t x = (uint32_t) d_minus_1;
uint32_t y = d_minus_1 >> 32;
if (y != 0) {
l_minus_1 += 32;
x = y;
}
y = x >> 16;
if (y != 0) {
l_minus_1 += 16;
x = y;
}
y = x >> 8;
if (y != 0) {
l_minus_1 += 8;
x = y;
}
y = x >> 4;
if (y != 0) {
l_minus_1 += 4;
x = y;
}
y = x >> 2;
if (y != 0) {
l_minus_1 += 2;
x = y;
}
if ((x & 2) != 0) {
l_minus_1 += 1;
}
const uint32_t nlz_d = (l_minus_1 ^ UINT32_C(0x3F)) - d_is_power_of_2;
#endif
uint64_t u_hi = (UINT64_C(2) << (uint32_t) l_minus_1) - d;
/* Division of 128-bit number u_hi:UINT64_C(0) by 64-bit number d, 64-bit quotient output q */
#if defined(__GNUC__) && defined(__x86_64__) && FXDIV_USE_INLINE_ASSEMBLY
uint64_t q;
__asm__("DIVQ %[d]"
: "=a" (q), "+d" (u_hi)
: [d] "r" (d), "a" (UINT64_C(0))
: "cc");
#elif 0 && defined(__GNUC__) && defined(__SIZEOF_INT128__)
/* GCC, Clang, and Intel Compiler fail to inline optimized implementation and call into support library for 128-bit division */
const uint64_t q = (uint64_t) (((unsigned __int128) u_hi << 64) / ((unsigned __int128) d));
#elif (defined(_MSC_VER) && _MSC_VER >= 1920) && !defined(__clang__) && !defined(__INTEL_COMPILER) && defined(_M_X64)
unsigned __int64 remainder;
const uint64_t q = (uint64_t) _udiv128((unsigned __int64) u_hi, 0, (unsigned __int64) d, &remainder);
#else
/* Implementation based on code from Hacker's delight */
/* Normalize divisor and shift divident left */
d <<= nlz_d;
u_hi <<= nlz_d;
/* Break divisor up into two 32-bit digits */
const uint64_t d_hi = (uint32_t) (d >> 32);
const uint32_t d_lo = (uint32_t) d;
/* Compute the first quotient digit, q1 */
uint64_t q1 = u_hi / d_hi;
uint64_t r1 = u_hi - q1 * d_hi;
while ((q1 >> 32) != 0 || fxdiv_mulext_uint32_t((uint32_t) q1, d_lo) > (r1 << 32)) {
q1 -= 1;
r1 += d_hi;
if ((r1 >> 32) != 0) {
break;
}
}
/* Multiply and subtract. */
u_hi = (u_hi << 32) - q1 * d;
/* Compute the second quotient digit, q0 */
uint64_t q0 = u_hi / d_hi;
uint64_t r0 = u_hi - q0 * d_hi;
while ((q0 >> 32) != 0 || fxdiv_mulext_uint32_t((uint32_t) q0, d_lo) > (r0 << 32)) {
q0 -= 1;
r0 += d_hi;
if ((r0 >> 32) != 0) {
break;
}
}
const uint64_t q = (q1 << 32) | (uint32_t) q0;
#endif
result.m = q + UINT64_C(1);
result.s1 = 1;
result.s2 = (uint8_t) l_minus_1;
}
return result;
}
static inline struct fxdiv_divisor_size_t fxdiv_init_size_t(size_t d) {
#if SIZE_MAX == UINT32_MAX
const struct fxdiv_divisor_uint32_t uint_result = fxdiv_init_uint32_t((uint32_t) d);
#elif SIZE_MAX == UINT64_MAX
const struct fxdiv_divisor_uint64_t uint_result = fxdiv_init_uint64_t((uint64_t) d);
#else
#error Unsupported platform
#endif
struct fxdiv_divisor_size_t size_result = {
(size_t) uint_result.value,
(size_t) uint_result.m,
uint_result.s1,
uint_result.s2
};
return size_result;
}
static inline uint32_t fxdiv_quotient_uint32_t(uint32_t n, const struct fxdiv_divisor_uint32_t divisor) {
const uint32_t t = fxdiv_mulhi_uint32_t(n, divisor.m);
return (t + ((n - t) >> divisor.s1)) >> divisor.s2;
}
static inline uint64_t fxdiv_quotient_uint64_t(uint64_t n, const struct fxdiv_divisor_uint64_t divisor) {
const uint64_t t = fxdiv_mulhi_uint64_t(n, divisor.m);
return (t + ((n - t) >> divisor.s1)) >> divisor.s2;
}
static inline size_t fxdiv_quotient_size_t(size_t n, const struct fxdiv_divisor_size_t divisor) {
#if SIZE_MAX == UINT32_MAX
const struct fxdiv_divisor_uint32_t uint32_divisor = {
(uint32_t) divisor.value,
(uint32_t) divisor.m,
divisor.s1,
divisor.s2
};
return fxdiv_quotient_uint32_t((uint32_t) n, uint32_divisor);
#elif SIZE_MAX == UINT64_MAX
const struct fxdiv_divisor_uint64_t uint64_divisor = {
(uint64_t) divisor.value,
(uint64_t) divisor.m,
divisor.s1,
divisor.s2
};
return fxdiv_quotient_uint64_t((uint64_t) n, uint64_divisor);
#else
#error Unsupported platform
#endif
}
static inline uint32_t fxdiv_remainder_uint32_t(uint32_t n, const struct fxdiv_divisor_uint32_t divisor) {
const uint32_t quotient = fxdiv_quotient_uint32_t(n, divisor);
return n - quotient * divisor.value;
}
static inline uint64_t fxdiv_remainder_uint64_t(uint64_t n, const struct fxdiv_divisor_uint64_t divisor) {
const uint64_t quotient = fxdiv_quotient_uint64_t(n, divisor);
return n - quotient * divisor.value;
}
static inline size_t fxdiv_remainder_size_t(size_t n, const struct fxdiv_divisor_size_t divisor) {
const size_t quotient = fxdiv_quotient_size_t(n, divisor);
return n - quotient * divisor.value;
}
static inline uint32_t fxdiv_round_down_uint32_t(uint32_t n, const struct fxdiv_divisor_uint32_t granularity) {
const uint32_t quotient = fxdiv_quotient_uint32_t(n, granularity);
return quotient * granularity.value;
}
static inline uint64_t fxdiv_round_down_uint64_t(uint64_t n, const struct fxdiv_divisor_uint64_t granularity) {
const uint64_t quotient = fxdiv_quotient_uint64_t(n, granularity);
return quotient * granularity.value;
}
static inline size_t fxdiv_round_down_size_t(size_t n, const struct fxdiv_divisor_size_t granularity) {
const size_t quotient = fxdiv_quotient_size_t(n, granularity);
return quotient * granularity.value;
}
static inline struct fxdiv_result_uint32_t fxdiv_divide_uint32_t(uint32_t n, const struct fxdiv_divisor_uint32_t divisor) {
const uint32_t quotient = fxdiv_quotient_uint32_t(n, divisor);
const uint32_t remainder = n - quotient * divisor.value;
struct fxdiv_result_uint32_t result = { quotient, remainder };
return result;
}
static inline struct fxdiv_result_uint64_t fxdiv_divide_uint64_t(uint64_t n, const struct fxdiv_divisor_uint64_t divisor) {
const uint64_t quotient = fxdiv_quotient_uint64_t(n, divisor);
const uint64_t remainder = n - quotient * divisor.value;
struct fxdiv_result_uint64_t result = { quotient, remainder };
return result;
}
static inline struct fxdiv_result_size_t fxdiv_divide_size_t(size_t n, const struct fxdiv_divisor_size_t divisor) {
const size_t quotient = fxdiv_quotient_size_t(n, divisor);
const size_t remainder = n - quotient * divisor.value;
struct fxdiv_result_size_t result = { quotient, remainder };
return result;
}
#endif /* FXDIV_H */