1 #ifndef _LINUX_MATH64_H 2 #define _LINUX_MATH64_H 3 4 #include <linux/types.h> 5 #include <asm/div64.h> 6 7 #if BITS_PER_LONG == 64 8 9 #define div64_long(x, y) div64_s64((x), (y)) 10 #define div64_ul(x, y) div64_u64((x), (y)) 11 12 /** 13 * div_u64_rem - unsigned 64bit divide with 32bit divisor with remainder 14 * 15 * This is commonly provided by 32bit archs to provide an optimized 64bit 16 * divide. 17 */ 18 static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder) 19 { 20 *remainder = dividend % divisor; 21 return dividend / divisor; 22 } 23 24 /** 25 * div_s64_rem - signed 64bit divide with 32bit divisor with remainder 26 */ 27 static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder) 28 { 29 *remainder = dividend % divisor; 30 return dividend / divisor; 31 } 32 33 /** 34 * div64_u64_rem - unsigned 64bit divide with 64bit divisor and remainder 35 */ 36 static inline u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder) 37 { 38 *remainder = dividend % divisor; 39 return dividend / divisor; 40 } 41 42 /** 43 * div64_u64 - unsigned 64bit divide with 64bit divisor 44 */ 45 static inline u64 div64_u64(u64 dividend, u64 divisor) 46 { 47 return dividend / divisor; 48 } 49 50 /** 51 * div64_s64 - signed 64bit divide with 64bit divisor 52 */ 53 static inline s64 div64_s64(s64 dividend, s64 divisor) 54 { 55 return dividend / divisor; 56 } 57 58 #elif BITS_PER_LONG == 32 59 60 #define div64_long(x, y) div_s64((x), (y)) 61 #define div64_ul(x, y) div_u64((x), (y)) 62 63 #ifndef div_u64_rem 64 static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder) 65 { 66 *remainder = do_div(dividend, divisor); 67 return dividend; 68 } 69 #endif 70 71 #ifndef div_s64_rem 72 extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder); 73 #endif 74 75 #ifndef div64_u64_rem 76 extern u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder); 77 #endif 78 79 #ifndef div64_u64 80 extern u64 div64_u64(u64 dividend, u64 divisor); 81 #endif 82 83 #ifndef div64_s64 84 extern s64 div64_s64(s64 dividend, s64 divisor); 85 #endif 86 87 #endif /* BITS_PER_LONG */ 88 89 /** 90 * div_u64 - unsigned 64bit divide with 32bit divisor 91 * 92 * This is the most common 64bit divide and should be used if possible, 93 * as many 32bit archs can optimize this variant better than a full 64bit 94 * divide. 95 */ 96 #ifndef div_u64 97 static inline u64 div_u64(u64 dividend, u32 divisor) 98 { 99 u32 remainder; 100 return div_u64_rem(dividend, divisor, &remainder); 101 } 102 #endif 103 104 /** 105 * div_s64 - signed 64bit divide with 32bit divisor 106 */ 107 #ifndef div_s64 108 static inline s64 div_s64(s64 dividend, s32 divisor) 109 { 110 s32 remainder; 111 return div_s64_rem(dividend, divisor, &remainder); 112 } 113 #endif 114 115 u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder); 116 117 static __always_inline u32 118 __iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder) 119 { 120 u32 ret = 0; 121 122 while (dividend >= divisor) { 123 /* The following asm() prevents the compiler from 124 optimising this loop into a modulo operation. */ 125 asm("" : "+rm"(dividend)); 126 127 dividend -= divisor; 128 ret++; 129 } 130 131 *remainder = dividend; 132 133 return ret; 134 } 135 136 #if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__) 137 138 #ifndef mul_u64_u32_shr 139 static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift) 140 { 141 return (u64)(((unsigned __int128)a * mul) >> shift); 142 } 143 #endif /* mul_u64_u32_shr */ 144 145 #ifndef mul_u64_u64_shr 146 static inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift) 147 { 148 return (u64)(((unsigned __int128)a * mul) >> shift); 149 } 150 #endif /* mul_u64_u64_shr */ 151 152 #else 153 154 #ifndef mul_u64_u32_shr 155 static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift) 156 { 157 u32 ah, al; 158 u64 ret; 159 160 al = a; 161 ah = a >> 32; 162 163 ret = ((u64)al * mul) >> shift; 164 if (ah) 165 ret += ((u64)ah * mul) << (32 - shift); 166 167 return ret; 168 } 169 #endif /* mul_u64_u32_shr */ 170 171 #ifndef mul_u64_u64_shr 172 static inline u64 mul_u64_u64_shr(u64 a, u64 b, unsigned int shift) 173 { 174 union { 175 u64 ll; 176 struct { 177 #ifdef __BIG_ENDIAN 178 u32 high, low; 179 #else 180 u32 low, high; 181 #endif 182 } l; 183 } rl, rm, rn, rh, a0, b0; 184 u64 c; 185 186 a0.ll = a; 187 b0.ll = b; 188 189 rl.ll = (u64)a0.l.low * b0.l.low; 190 rm.ll = (u64)a0.l.low * b0.l.high; 191 rn.ll = (u64)a0.l.high * b0.l.low; 192 rh.ll = (u64)a0.l.high * b0.l.high; 193 194 /* 195 * Each of these lines computes a 64-bit intermediate result into "c", 196 * starting at bits 32-95. The low 32-bits go into the result of the 197 * multiplication, the high 32-bits are carried into the next step. 198 */ 199 rl.l.high = c = (u64)rl.l.high + rm.l.low + rn.l.low; 200 rh.l.low = c = (c >> 32) + rm.l.high + rn.l.high + rh.l.low; 201 rh.l.high = (c >> 32) + rh.l.high; 202 203 /* 204 * The 128-bit result of the multiplication is in rl.ll and rh.ll, 205 * shift it right and throw away the high part of the result. 206 */ 207 if (shift == 0) 208 return rl.ll; 209 if (shift < 64) 210 return (rl.ll >> shift) | (rh.ll << (64 - shift)); 211 return rh.ll >> (shift & 63); 212 } 213 #endif /* mul_u64_u64_shr */ 214 215 #endif 216 217 #ifndef mul_u64_u32_div 218 static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor) 219 { 220 union { 221 u64 ll; 222 struct { 223 #ifdef __BIG_ENDIAN 224 u32 high, low; 225 #else 226 u32 low, high; 227 #endif 228 } l; 229 } u, rl, rh; 230 231 u.ll = a; 232 rl.ll = (u64)u.l.low * mul; 233 rh.ll = (u64)u.l.high * mul + rl.l.high; 234 235 /* Bits 32-63 of the result will be in rh.l.low. */ 236 rl.l.high = do_div(rh.ll, divisor); 237 238 /* Bits 0-31 of the result will be in rl.l.low. */ 239 do_div(rl.ll, divisor); 240 241 rl.l.high = rh.l.low; 242 return rl.ll; 243 } 244 #endif /* mul_u64_u32_div */ 245 246 #endif /* _LINUX_MATH64_H */ 247