1 | /* SPDX-License-Identifier: GPL-2.0 */ |
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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: &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: &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 __always_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), mul: 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 |