math64.h (8112B)
1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef _LINUX_MATH64_H 3#define _LINUX_MATH64_H 4 5#include <linux/types.h> 6#include <linux/math.h> 7#include <vdso/math64.h> 8#include <asm/div64.h> 9 10#if BITS_PER_LONG == 64 11 12#define div64_long(x, y) div64_s64((x), (y)) 13#define div64_ul(x, y) div64_u64((x), (y)) 14 15/** 16 * div_u64_rem - unsigned 64bit divide with 32bit divisor with remainder 17 * @dividend: unsigned 64bit dividend 18 * @divisor: unsigned 32bit divisor 19 * @remainder: pointer to unsigned 32bit remainder 20 * 21 * Return: sets ``*remainder``, then returns dividend / divisor 22 * 23 * This is commonly provided by 32bit archs to provide an optimized 64bit 24 * divide. 25 */ 26static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder) 27{ 28 *remainder = dividend % divisor; 29 return dividend / divisor; 30} 31 32/* 33 * div_s64_rem - signed 64bit divide with 32bit divisor with remainder 34 * @dividend: signed 64bit dividend 35 * @divisor: signed 32bit divisor 36 * @remainder: pointer to signed 32bit remainder 37 * 38 * Return: sets ``*remainder``, then returns dividend / divisor 39 */ 40static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder) 41{ 42 *remainder = dividend % divisor; 43 return dividend / divisor; 44} 45 46/* 47 * div64_u64_rem - unsigned 64bit divide with 64bit divisor and remainder 48 * @dividend: unsigned 64bit dividend 49 * @divisor: unsigned 64bit divisor 50 * @remainder: pointer to unsigned 64bit remainder 51 * 52 * Return: sets ``*remainder``, then returns dividend / divisor 53 */ 54static inline u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder) 55{ 56 *remainder = dividend % divisor; 57 return dividend / divisor; 58} 59 60/* 61 * div64_u64 - unsigned 64bit divide with 64bit divisor 62 * @dividend: unsigned 64bit dividend 63 * @divisor: unsigned 64bit divisor 64 * 65 * Return: dividend / divisor 66 */ 67static inline u64 div64_u64(u64 dividend, u64 divisor) 68{ 69 return dividend / divisor; 70} 71 72/* 73 * div64_s64 - signed 64bit divide with 64bit divisor 74 * @dividend: signed 64bit dividend 75 * @divisor: signed 64bit divisor 76 * 77 * Return: dividend / divisor 78 */ 79static inline s64 div64_s64(s64 dividend, s64 divisor) 80{ 81 return dividend / divisor; 82} 83 84#elif BITS_PER_LONG == 32 85 86#define div64_long(x, y) div_s64((x), (y)) 87#define div64_ul(x, y) div_u64((x), (y)) 88 89#ifndef div_u64_rem 90static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder) 91{ 92 *remainder = do_div(dividend, divisor); 93 return dividend; 94} 95#endif 96 97#ifndef div_s64_rem 98extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder); 99#endif 100 101#ifndef div64_u64_rem 102extern u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder); 103#endif 104 105#ifndef div64_u64 106extern u64 div64_u64(u64 dividend, u64 divisor); 107#endif 108 109#ifndef div64_s64 110extern s64 div64_s64(s64 dividend, s64 divisor); 111#endif 112 113#endif /* BITS_PER_LONG */ 114 115/** 116 * div_u64 - unsigned 64bit divide with 32bit divisor 117 * @dividend: unsigned 64bit dividend 118 * @divisor: unsigned 32bit divisor 119 * 120 * This is the most common 64bit divide and should be used if possible, 121 * as many 32bit archs can optimize this variant better than a full 64bit 122 * divide. 123 */ 124#ifndef div_u64 125static inline u64 div_u64(u64 dividend, u32 divisor) 126{ 127 u32 remainder; 128 return div_u64_rem(dividend, divisor, &remainder); 129} 130#endif 131 132/** 133 * div_s64 - signed 64bit divide with 32bit divisor 134 * @dividend: signed 64bit dividend 135 * @divisor: signed 32bit divisor 136 */ 137#ifndef div_s64 138static inline s64 div_s64(s64 dividend, s32 divisor) 139{ 140 s32 remainder; 141 return div_s64_rem(dividend, divisor, &remainder); 142} 143#endif 144 145u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder); 146 147#ifndef mul_u32_u32 148/* 149 * Many a GCC version messes this up and generates a 64x64 mult :-( 150 */ 151static inline u64 mul_u32_u32(u32 a, u32 b) 152{ 153 return (u64)a * b; 154} 155#endif 156 157#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__) 158 159#ifndef mul_u64_u32_shr 160static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift) 161{ 162 return (u64)(((unsigned __int128)a * mul) >> shift); 163} 164#endif /* mul_u64_u32_shr */ 165 166#ifndef mul_u64_u64_shr 167static inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift) 168{ 169 return (u64)(((unsigned __int128)a * mul) >> shift); 170} 171#endif /* mul_u64_u64_shr */ 172 173#else 174 175#ifndef mul_u64_u32_shr 176static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift) 177{ 178 u32 ah, al; 179 u64 ret; 180 181 al = a; 182 ah = a >> 32; 183 184 ret = mul_u32_u32(al, mul) >> shift; 185 if (ah) 186 ret += mul_u32_u32(ah, mul) << (32 - shift); 187 188 return ret; 189} 190#endif /* mul_u64_u32_shr */ 191 192#ifndef mul_u64_u64_shr 193static inline u64 mul_u64_u64_shr(u64 a, u64 b, unsigned int shift) 194{ 195 union { 196 u64 ll; 197 struct { 198#ifdef __BIG_ENDIAN 199 u32 high, low; 200#else 201 u32 low, high; 202#endif 203 } l; 204 } rl, rm, rn, rh, a0, b0; 205 u64 c; 206 207 a0.ll = a; 208 b0.ll = b; 209 210 rl.ll = mul_u32_u32(a0.l.low, b0.l.low); 211 rm.ll = mul_u32_u32(a0.l.low, b0.l.high); 212 rn.ll = mul_u32_u32(a0.l.high, b0.l.low); 213 rh.ll = mul_u32_u32(a0.l.high, b0.l.high); 214 215 /* 216 * Each of these lines computes a 64-bit intermediate result into "c", 217 * starting at bits 32-95. The low 32-bits go into the result of the 218 * multiplication, the high 32-bits are carried into the next step. 219 */ 220 rl.l.high = c = (u64)rl.l.high + rm.l.low + rn.l.low; 221 rh.l.low = c = (c >> 32) + rm.l.high + rn.l.high + rh.l.low; 222 rh.l.high = (c >> 32) + rh.l.high; 223 224 /* 225 * The 128-bit result of the multiplication is in rl.ll and rh.ll, 226 * shift it right and throw away the high part of the result. 227 */ 228 if (shift == 0) 229 return rl.ll; 230 if (shift < 64) 231 return (rl.ll >> shift) | (rh.ll << (64 - shift)); 232 return rh.ll >> (shift & 63); 233} 234#endif /* mul_u64_u64_shr */ 235 236#endif 237 238#ifndef mul_s64_u64_shr 239static inline u64 mul_s64_u64_shr(s64 a, u64 b, unsigned int shift) 240{ 241 u64 ret; 242 243 /* 244 * Extract the sign before the multiplication and put it back 245 * afterwards if needed. 246 */ 247 ret = mul_u64_u64_shr(abs(a), b, shift); 248 249 if (a < 0) 250 ret = -((s64) ret); 251 252 return ret; 253} 254#endif /* mul_s64_u64_shr */ 255 256#ifndef mul_u64_u32_div 257static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor) 258{ 259 union { 260 u64 ll; 261 struct { 262#ifdef __BIG_ENDIAN 263 u32 high, low; 264#else 265 u32 low, high; 266#endif 267 } l; 268 } u, rl, rh; 269 270 u.ll = a; 271 rl.ll = mul_u32_u32(u.l.low, mul); 272 rh.ll = mul_u32_u32(u.l.high, mul) + rl.l.high; 273 274 /* Bits 32-63 of the result will be in rh.l.low. */ 275 rl.l.high = do_div(rh.ll, divisor); 276 277 /* Bits 0-31 of the result will be in rl.l.low. */ 278 do_div(rl.ll, divisor); 279 280 rl.l.high = rh.l.low; 281 return rl.ll; 282} 283#endif /* mul_u64_u32_div */ 284 285u64 mul_u64_u64_div_u64(u64 a, u64 mul, u64 div); 286 287#define DIV64_U64_ROUND_UP(ll, d) \ 288 ({ u64 _tmp = (d); div64_u64((ll) + _tmp - 1, _tmp); }) 289 290/** 291 * DIV64_U64_ROUND_CLOSEST - unsigned 64bit divide with 64bit divisor rounded to nearest integer 292 * @dividend: unsigned 64bit dividend 293 * @divisor: unsigned 64bit divisor 294 * 295 * Divide unsigned 64bit dividend by unsigned 64bit divisor 296 * and round to closest integer. 297 * 298 * Return: dividend / divisor rounded to nearest integer 299 */ 300#define DIV64_U64_ROUND_CLOSEST(dividend, divisor) \ 301 ({ u64 _tmp = (divisor); div64_u64((dividend) + _tmp / 2, _tmp); }) 302 303/* 304 * DIV_U64_ROUND_CLOSEST - unsigned 64bit divide with 32bit divisor rounded to nearest integer 305 * @dividend: unsigned 64bit dividend 306 * @divisor: unsigned 32bit divisor 307 * 308 * Divide unsigned 64bit dividend by unsigned 32bit divisor 309 * and round to closest integer. 310 * 311 * Return: dividend / divisor rounded to nearest integer 312 */ 313#define DIV_U64_ROUND_CLOSEST(dividend, divisor) \ 314 ({ u32 _tmp = (divisor); div_u64((u64)(dividend) + _tmp / 2, _tmp); }) 315 316/* 317 * DIV_S64_ROUND_CLOSEST - signed 64bit divide with 32bit divisor rounded to nearest integer 318 * @dividend: signed 64bit dividend 319 * @divisor: signed 32bit divisor 320 * 321 * Divide signed 64bit dividend by signed 32bit divisor 322 * and round to closest integer. 323 * 324 * Return: dividend / divisor rounded to nearest integer 325 */ 326#define DIV_S64_ROUND_CLOSEST(dividend, divisor)( \ 327{ \ 328 s64 __x = (dividend); \ 329 s32 __d = (divisor); \ 330 ((__x > 0) == (__d > 0)) ? \ 331 div_s64((__x + (__d / 2)), __d) : \ 332 div_s64((__x - (__d / 2)), __d); \ 333} \ 334) 335#endif /* _LINUX_MATH64_H */