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 */ 26 static 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 */ 40 static 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 */ 54 static 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 */ 67 static 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 */ 79 static 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 90 static 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 98 extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder); 99 #endif 100 101 #ifndef div64_u64_rem 102 extern u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder); 103 #endif 104 105 #ifndef div64_u64 106 extern u64 div64_u64(u64 dividend, u64 divisor); 107 #endif 108 109 #ifndef div64_s64 110 extern 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 * Return: dividend / divisor 125 */ 126 #ifndef div_u64 127 static inline u64 div_u64(u64 dividend, u32 divisor) 128 { 129 u32 remainder; 130 return div_u64_rem(dividend, divisor, &remainder); 131 } 132 #endif 133 134 /** 135 * div_s64 - signed 64bit divide with 32bit divisor 136 * @dividend: signed 64bit dividend 137 * @divisor: signed 32bit divisor 138 * 139 * Return: dividend / divisor 140 */ 141 #ifndef div_s64 142 static inline s64 div_s64(s64 dividend, s32 divisor) 143 { 144 s32 remainder; 145 return div_s64_rem(dividend, divisor, &remainder); 146 } 147 #endif 148 149 u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder); 150 151 #ifndef mul_u32_u32 152 /* 153 * Many a GCC version messes this up and generates a 64x64 mult :-( 154 */ 155 static inline u64 mul_u32_u32(u32 a, u32 b) 156 { 157 return (u64)a * b; 158 } 159 #endif 160 161 #if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__) 162 163 #ifndef mul_u64_u32_shr 164 static __always_inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift) 165 { 166 return (u64)(((unsigned __int128)a * mul) >> shift); 167 } 168 #endif /* mul_u64_u32_shr */ 169 170 #ifndef mul_u64_u64_shr 171 static inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift) 172 { 173 return (u64)(((unsigned __int128)a * mul) >> shift); 174 } 175 #endif /* mul_u64_u64_shr */ 176 177 #else 178 179 #ifndef mul_u64_u32_shr 180 static __always_inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift) 181 { 182 u32 ah, al; 183 u64 ret; 184 185 al = a; 186 ah = a >> 32; 187 188 ret = mul_u32_u32(al, mul) >> shift; 189 if (ah) 190 ret += mul_u32_u32(ah, mul) << (32 - shift); 191 192 return ret; 193 } 194 #endif /* mul_u64_u32_shr */ 195 196 #ifndef mul_u64_u64_shr 197 static inline u64 mul_u64_u64_shr(u64 a, u64 b, unsigned int shift) 198 { 199 union { 200 u64 ll; 201 struct { 202 #ifdef __BIG_ENDIAN 203 u32 high, low; 204 #else 205 u32 low, high; 206 #endif 207 } l; 208 } rl, rm, rn, rh, a0, b0; 209 u64 c; 210 211 a0.ll = a; 212 b0.ll = b; 213 214 rl.ll = mul_u32_u32(a0.l.low, b0.l.low); 215 rm.ll = mul_u32_u32(a0.l.low, b0.l.high); 216 rn.ll = mul_u32_u32(a0.l.high, b0.l.low); 217 rh.ll = mul_u32_u32(a0.l.high, b0.l.high); 218 219 /* 220 * Each of these lines computes a 64-bit intermediate result into "c", 221 * starting at bits 32-95. The low 32-bits go into the result of the 222 * multiplication, the high 32-bits are carried into the next step. 223 */ 224 rl.l.high = c = (u64)rl.l.high + rm.l.low + rn.l.low; 225 rh.l.low = c = (c >> 32) + rm.l.high + rn.l.high + rh.l.low; 226 rh.l.high = (c >> 32) + rh.l.high; 227 228 /* 229 * The 128-bit result of the multiplication is in rl.ll and rh.ll, 230 * shift it right and throw away the high part of the result. 231 */ 232 if (shift == 0) 233 return rl.ll; 234 if (shift < 64) 235 return (rl.ll >> shift) | (rh.ll << (64 - shift)); 236 return rh.ll >> (shift & 63); 237 } 238 #endif /* mul_u64_u64_shr */ 239 240 #endif 241 242 #ifndef mul_s64_u64_shr 243 static inline u64 mul_s64_u64_shr(s64 a, u64 b, unsigned int shift) 244 { 245 u64 ret; 246 247 /* 248 * Extract the sign before the multiplication and put it back 249 * afterwards if needed. 250 */ 251 ret = mul_u64_u64_shr(abs(a), b, shift); 252 253 if (a < 0) 254 ret = -((s64) ret); 255 256 return ret; 257 } 258 #endif /* mul_s64_u64_shr */ 259 260 #ifndef mul_u64_u32_div 261 static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor) 262 { 263 union { 264 u64 ll; 265 struct { 266 #ifdef __BIG_ENDIAN 267 u32 high, low; 268 #else 269 u32 low, high; 270 #endif 271 } l; 272 } u, rl, rh; 273 274 u.ll = a; 275 rl.ll = mul_u32_u32(u.l.low, mul); 276 rh.ll = mul_u32_u32(u.l.high, mul) + rl.l.high; 277 278 /* Bits 32-63 of the result will be in rh.l.low. */ 279 rl.l.high = do_div(rh.ll, divisor); 280 281 /* Bits 0-31 of the result will be in rl.l.low. */ 282 do_div(rl.ll, divisor); 283 284 rl.l.high = rh.l.low; 285 return rl.ll; 286 } 287 #endif /* mul_u64_u32_div */ 288 289 u64 mul_u64_u64_div_u64(u64 a, u64 mul, u64 div); 290 291 /** 292 * DIV64_U64_ROUND_UP - unsigned 64bit divide with 64bit divisor rounded up 293 * @ll: unsigned 64bit dividend 294 * @d: unsigned 64bit divisor 295 * 296 * Divide unsigned 64bit dividend by unsigned 64bit divisor 297 * and round up. 298 * 299 * Return: dividend / divisor rounded up 300 */ 301 #define DIV64_U64_ROUND_UP(ll, d) \ 302 ({ u64 _tmp = (d); div64_u64((ll) + _tmp - 1, _tmp); }) 303 304 /** 305 * DIV64_U64_ROUND_CLOSEST - unsigned 64bit divide with 64bit divisor rounded to nearest integer 306 * @dividend: unsigned 64bit dividend 307 * @divisor: unsigned 64bit divisor 308 * 309 * Divide unsigned 64bit dividend by unsigned 64bit divisor 310 * and round to closest integer. 311 * 312 * Return: dividend / divisor rounded to nearest integer 313 */ 314 #define DIV64_U64_ROUND_CLOSEST(dividend, divisor) \ 315 ({ u64 _tmp = (divisor); div64_u64((dividend) + _tmp / 2, _tmp); }) 316 317 /** 318 * DIV_U64_ROUND_CLOSEST - unsigned 64bit divide with 32bit divisor rounded to nearest integer 319 * @dividend: unsigned 64bit dividend 320 * @divisor: unsigned 32bit divisor 321 * 322 * Divide unsigned 64bit dividend by unsigned 32bit divisor 323 * and round to closest integer. 324 * 325 * Return: dividend / divisor rounded to nearest integer 326 */ 327 #define DIV_U64_ROUND_CLOSEST(dividend, divisor) \ 328 ({ u32 _tmp = (divisor); div_u64((u64)(dividend) + _tmp / 2, _tmp); }) 329 330 /** 331 * DIV_S64_ROUND_CLOSEST - signed 64bit divide with 32bit divisor rounded to nearest integer 332 * @dividend: signed 64bit dividend 333 * @divisor: signed 32bit divisor 334 * 335 * Divide signed 64bit dividend by signed 32bit divisor 336 * and round to closest integer. 337 * 338 * Return: dividend / divisor rounded to nearest integer 339 */ 340 #define DIV_S64_ROUND_CLOSEST(dividend, divisor)( \ 341 { \ 342 s64 __x = (dividend); \ 343 s32 __d = (divisor); \ 344 ((__x > 0) == (__d > 0)) ? \ 345 div_s64((__x + (__d / 2)), __d) : \ 346 div_s64((__x - (__d / 2)), __d); \ 347 } \ 348 ) 349 #endif /* _LINUX_MATH64_H */ 350