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 <asm/div64.h> |

7 | |

8 | #if BITS_PER_LONG == 64 |

9 | |

10 | #define div64_long(x, y) div64_s64((x), (y)) |

11 | #define div64_ul(x, y) div64_u64((x), (y)) |

12 | |

13 | /** |

14 | * div_u64_rem - unsigned 64bit divide with 32bit divisor with remainder |

15 | * @dividend: unsigned 64bit dividend |

16 | * @divisor: unsigned 32bit divisor |

17 | * @remainder: pointer to unsigned 32bit remainder |

18 | * |

19 | * Return: sets ``*remainder``, then returns dividend / divisor |

20 | * |

21 | * This is commonly provided by 32bit archs to provide an optimized 64bit |

22 | * divide. |

23 | */ |

24 | static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder) |

25 | { |

26 | *remainder = dividend % divisor; |

27 | return dividend / divisor; |

28 | } |

29 | |

30 | /** |

31 | * div_s64_rem - signed 64bit divide with 32bit divisor with remainder |

32 | * @dividend: signed 64bit dividend |

33 | * @divisor: signed 32bit divisor |

34 | * @remainder: pointer to signed 32bit remainder |

35 | * |

36 | * Return: sets ``*remainder``, then returns dividend / divisor |

37 | */ |

38 | static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder) |

39 | { |

40 | *remainder = dividend % divisor; |

41 | return dividend / divisor; |

42 | } |

43 | |

44 | /** |

45 | * div64_u64_rem - unsigned 64bit divide with 64bit divisor and remainder |

46 | * @dividend: unsigned 64bit dividend |

47 | * @divisor: unsigned 64bit divisor |

48 | * @remainder: pointer to unsigned 64bit remainder |

49 | * |

50 | * Return: sets ``*remainder``, then returns dividend / divisor |

51 | */ |

52 | static inline u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder) |

53 | { |

54 | *remainder = dividend % divisor; |

55 | return dividend / divisor; |

56 | } |

57 | |

58 | /** |

59 | * div64_u64 - unsigned 64bit divide with 64bit divisor |

60 | * @dividend: unsigned 64bit dividend |

61 | * @divisor: unsigned 64bit divisor |

62 | * |

63 | * Return: dividend / divisor |

64 | */ |

65 | static inline u64 div64_u64(u64 dividend, u64 divisor) |

66 | { |

67 | return dividend / divisor; |

68 | } |

69 | |

70 | /** |

71 | * div64_s64 - signed 64bit divide with 64bit divisor |

72 | * @dividend: signed 64bit dividend |

73 | * @divisor: signed 64bit divisor |

74 | * |

75 | * Return: dividend / divisor |

76 | */ |

77 | static inline s64 div64_s64(s64 dividend, s64 divisor) |

78 | { |

79 | return dividend / divisor; |

80 | } |

81 | |

82 | #elif BITS_PER_LONG == 32 |

83 | |

84 | #define div64_long(x, y) div_s64((x), (y)) |

85 | #define div64_ul(x, y) div_u64((x), (y)) |

86 | |

87 | #ifndef div_u64_rem |

88 | static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder) |

89 | { |

90 | *remainder = do_div(dividend, divisor); |

91 | return dividend; |

92 | } |

93 | #endif |

94 | |

95 | #ifndef div_s64_rem |

96 | extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder); |

97 | #endif |

98 | |

99 | #ifndef div64_u64_rem |

100 | extern u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder); |

101 | #endif |

102 | |

103 | #ifndef div64_u64 |

104 | extern u64 div64_u64(u64 dividend, u64 divisor); |

105 | #endif |

106 | |

107 | #ifndef div64_s64 |

108 | extern s64 div64_s64(s64 dividend, s64 divisor); |

109 | #endif |

110 | |

111 | #endif /* BITS_PER_LONG */ |

112 | |

113 | /** |

114 | * div_u64 - unsigned 64bit divide with 32bit divisor |

115 | * @dividend: unsigned 64bit dividend |

116 | * @divisor: unsigned 32bit divisor |

117 | * |

118 | * This is the most common 64bit divide and should be used if possible, |

119 | * as many 32bit archs can optimize this variant better than a full 64bit |

120 | * divide. |

121 | */ |

122 | #ifndef div_u64 |

123 | static inline u64 div_u64(u64 dividend, u32 divisor) |

124 | { |

125 | u32 remainder; |

126 | return div_u64_rem(dividend, divisor, &remainder); |

127 | } |

128 | #endif |

129 | |

130 | /** |

131 | * div_s64 - signed 64bit divide with 32bit divisor |

132 | * @dividend: signed 64bit dividend |

133 | * @divisor: signed 32bit divisor |

134 | */ |

135 | #ifndef div_s64 |

136 | static inline s64 div_s64(s64 dividend, s32 divisor) |

137 | { |

138 | s32 remainder; |

139 | return div_s64_rem(dividend, divisor, &remainder); |

140 | } |

141 | #endif |

142 | |

143 | u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder); |

144 | |

145 | static __always_inline u32 |

146 | __iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder) |

147 | { |

148 | u32 ret = 0; |

149 | |

150 | while (dividend >= divisor) { |

151 | /* The following asm() prevents the compiler from |

152 | optimising this loop into a modulo operation. */ |

153 | asm("": "+rm"(dividend)); |

154 | |

155 | dividend -= divisor; |

156 | ret++; |

157 | } |

158 | |

159 | *remainder = dividend; |

160 | |

161 | return ret; |

162 | } |

163 | |

164 | #ifndef mul_u32_u32 |

165 | /* |

166 | * Many a GCC version messes this up and generates a 64x64 mult :-( |

167 | */ |

168 | static inline u64 mul_u32_u32(u32 a, u32 b) |

169 | { |

170 | return (u64)a * b; |

171 | } |

172 | #endif |

173 | |

174 | #if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__) |

175 | |

176 | #ifndef mul_u64_u32_shr |

177 | static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift) |

178 | { |

179 | return (u64)(((unsigned __int128)a * mul) >> shift); |

180 | } |

181 | #endif /* mul_u64_u32_shr */ |

182 | |

183 | #ifndef mul_u64_u64_shr |

184 | static inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift) |

185 | { |

186 | return (u64)(((unsigned __int128)a * mul) >> shift); |

187 | } |

188 | #endif /* mul_u64_u64_shr */ |

189 | |

190 | #else |

191 | |

192 | #ifndef mul_u64_u32_shr |

193 | static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift) |

194 | { |

195 | u32 ah, al; |

196 | u64 ret; |

197 | |

198 | al = a; |

199 | ah = a >> 32; |

200 | |

201 | ret = mul_u32_u32(al, mul) >> shift; |

202 | if (ah) |

203 | ret += mul_u32_u32(ah, mul) << (32 - shift); |

204 | |

205 | return ret; |

206 | } |

207 | #endif /* mul_u64_u32_shr */ |

208 | |

209 | #ifndef mul_u64_u64_shr |

210 | static inline u64 mul_u64_u64_shr(u64 a, u64 b, unsigned int shift) |

211 | { |

212 | union { |

213 | u64 ll; |

214 | struct { |

215 | #ifdef __BIG_ENDIAN |

216 | u32 high, low; |

217 | #else |

218 | u32 low, high; |

219 | #endif |

220 | } l; |

221 | } rl, rm, rn, rh, a0, b0; |

222 | u64 c; |

223 | |

224 | a0.ll = a; |

225 | b0.ll = b; |

226 | |

227 | rl.ll = mul_u32_u32(a0.l.low, b0.l.low); |

228 | rm.ll = mul_u32_u32(a0.l.low, b0.l.high); |

229 | rn.ll = mul_u32_u32(a0.l.high, b0.l.low); |

230 | rh.ll = mul_u32_u32(a0.l.high, b0.l.high); |

231 | |

232 | /* |

233 | * Each of these lines computes a 64-bit intermediate result into "c", |

234 | * starting at bits 32-95. The low 32-bits go into the result of the |

235 | * multiplication, the high 32-bits are carried into the next step. |

236 | */ |

237 | rl.l.high = c = (u64)rl.l.high + rm.l.low + rn.l.low; |

238 | rh.l.low = c = (c >> 32) + rm.l.high + rn.l.high + rh.l.low; |

239 | rh.l.high = (c >> 32) + rh.l.high; |

240 | |

241 | /* |

242 | * The 128-bit result of the multiplication is in rl.ll and rh.ll, |

243 | * shift it right and throw away the high part of the result. |

244 | */ |

245 | if (shift == 0) |

246 | return rl.ll; |

247 | if (shift < 64) |

248 | return (rl.ll >> shift) | (rh.ll << (64 - shift)); |

249 | return rh.ll >> (shift & 63); |

250 | } |

251 | #endif /* mul_u64_u64_shr */ |

252 | |

253 | #endif |

254 | |

255 | #ifndef mul_u64_u32_div |

256 | static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor) |

257 | { |

258 | union { |

259 | u64 ll; |

260 | struct { |

261 | #ifdef __BIG_ENDIAN |

262 | u32 high, low; |

263 | #else |

264 | u32 low, high; |

265 | #endif |

266 | } l; |

267 | } u, rl, rh; |

268 | |

269 | u.ll = a; |

270 | rl.ll = mul_u32_u32(u.l.low, mul); |

271 | rh.ll = mul_u32_u32(u.l.high, mul) + rl.l.high; |

272 | |

273 | /* Bits 32-63 of the result will be in rh.l.low. */ |

274 | rl.l.high = do_div(rh.ll, divisor); |

275 | |

276 | /* Bits 0-31 of the result will be in rl.l.low. */ |

277 | do_div(rl.ll, divisor); |

278 | |

279 | rl.l.high = rh.l.low; |

280 | return rl.ll; |

281 | } |

282 | #endif /* mul_u64_u32_div */ |

283 | |

284 | #define DIV64_U64_ROUND_UP(ll, d) \ |

285 | ({ u64 _tmp = (d); div64_u64((ll) + _tmp - 1, _tmp); }) |

286 | |

287 | #endif /* _LINUX_MATH64_H */ |

288 |