diff options
Diffstat (limited to 'include/linux/math64.h')
-rw-r--r-- | include/linux/math64.h | 303 |
1 files changed, 303 insertions, 0 deletions
diff --git a/include/linux/math64.h b/include/linux/math64.h new file mode 100644 index 000000000..66deb1fdc --- /dev/null +++ b/include/linux/math64.h @@ -0,0 +1,303 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_MATH64_H +#define _LINUX_MATH64_H + +#include <linux/types.h> +#include <vdso/math64.h> +#include <asm/div64.h> + +#if BITS_PER_LONG == 64 + +#define div64_long(x, y) div64_s64((x), (y)) +#define div64_ul(x, y) div64_u64((x), (y)) + +/** + * div_u64_rem - unsigned 64bit divide with 32bit divisor with remainder + * @dividend: unsigned 64bit dividend + * @divisor: unsigned 32bit divisor + * @remainder: pointer to unsigned 32bit remainder + * + * Return: sets ``*remainder``, then returns dividend / divisor + * + * This is commonly provided by 32bit archs to provide an optimized 64bit + * divide. + */ +static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder) +{ + *remainder = dividend % divisor; + return dividend / divisor; +} + +/* + * div_s64_rem - signed 64bit divide with 32bit divisor with remainder + * @dividend: signed 64bit dividend + * @divisor: signed 32bit divisor + * @remainder: pointer to signed 32bit remainder + * + * Return: sets ``*remainder``, then returns dividend / divisor + */ +static inline s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder) +{ + *remainder = dividend % divisor; + return dividend / divisor; +} + +/* + * div64_u64_rem - unsigned 64bit divide with 64bit divisor and remainder + * @dividend: unsigned 64bit dividend + * @divisor: unsigned 64bit divisor + * @remainder: pointer to unsigned 64bit remainder + * + * Return: sets ``*remainder``, then returns dividend / divisor + */ +static inline u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder) +{ + *remainder = dividend % divisor; + return dividend / divisor; +} + +/* + * div64_u64 - unsigned 64bit divide with 64bit divisor + * @dividend: unsigned 64bit dividend + * @divisor: unsigned 64bit divisor + * + * Return: dividend / divisor + */ +static inline u64 div64_u64(u64 dividend, u64 divisor) +{ + return dividend / divisor; +} + +/* + * div64_s64 - signed 64bit divide with 64bit divisor + * @dividend: signed 64bit dividend + * @divisor: signed 64bit divisor + * + * Return: dividend / divisor + */ +static inline s64 div64_s64(s64 dividend, s64 divisor) +{ + return dividend / divisor; +} + +#elif BITS_PER_LONG == 32 + +#define div64_long(x, y) div_s64((x), (y)) +#define div64_ul(x, y) div_u64((x), (y)) + +#ifndef div_u64_rem +static inline u64 div_u64_rem(u64 dividend, u32 divisor, u32 *remainder) +{ + *remainder = do_div(dividend, divisor); + return dividend; +} +#endif + +#ifndef div_s64_rem +extern s64 div_s64_rem(s64 dividend, s32 divisor, s32 *remainder); +#endif + +#ifndef div64_u64_rem +extern u64 div64_u64_rem(u64 dividend, u64 divisor, u64 *remainder); +#endif + +#ifndef div64_u64 +extern u64 div64_u64(u64 dividend, u64 divisor); +#endif + +#ifndef div64_s64 +extern s64 div64_s64(s64 dividend, s64 divisor); +#endif + +#endif /* BITS_PER_LONG */ + +/** + * div_u64 - unsigned 64bit divide with 32bit divisor + * @dividend: unsigned 64bit dividend + * @divisor: unsigned 32bit divisor + * + * This is the most common 64bit divide and should be used if possible, + * as many 32bit archs can optimize this variant better than a full 64bit + * divide. + */ +#ifndef div_u64 +static inline u64 div_u64(u64 dividend, u32 divisor) +{ + u32 remainder; + return div_u64_rem(dividend, divisor, &remainder); +} +#endif + +/** + * div_s64 - signed 64bit divide with 32bit divisor + * @dividend: signed 64bit dividend + * @divisor: signed 32bit divisor + */ +#ifndef div_s64 +static inline s64 div_s64(s64 dividend, s32 divisor) +{ + s32 remainder; + return div_s64_rem(dividend, divisor, &remainder); +} +#endif + +u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder); + +#ifndef mul_u32_u32 +/* + * Many a GCC version messes this up and generates a 64x64 mult :-( + */ +static inline u64 mul_u32_u32(u32 a, u32 b) +{ + return (u64)a * b; +} +#endif + +#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__) + +#ifndef mul_u64_u32_shr +static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift) +{ + return (u64)(((unsigned __int128)a * mul) >> shift); +} +#endif /* mul_u64_u32_shr */ + +#ifndef mul_u64_u64_shr +static inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift) +{ + return (u64)(((unsigned __int128)a * mul) >> shift); +} +#endif /* mul_u64_u64_shr */ + +#else + +#ifndef mul_u64_u32_shr +static inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift) +{ + u32 ah, al; + u64 ret; + + al = a; + ah = a >> 32; + + ret = mul_u32_u32(al, mul) >> shift; + if (ah) + ret += mul_u32_u32(ah, mul) << (32 - shift); + + return ret; +} +#endif /* mul_u64_u32_shr */ + +#ifndef mul_u64_u64_shr +static inline u64 mul_u64_u64_shr(u64 a, u64 b, unsigned int shift) +{ + union { + u64 ll; + struct { +#ifdef __BIG_ENDIAN + u32 high, low; +#else + u32 low, high; +#endif + } l; + } rl, rm, rn, rh, a0, b0; + u64 c; + + a0.ll = a; + b0.ll = b; + + rl.ll = mul_u32_u32(a0.l.low, b0.l.low); + rm.ll = mul_u32_u32(a0.l.low, b0.l.high); + rn.ll = mul_u32_u32(a0.l.high, b0.l.low); + rh.ll = mul_u32_u32(a0.l.high, b0.l.high); + + /* + * Each of these lines computes a 64-bit intermediate result into "c", + * starting at bits 32-95. The low 32-bits go into the result of the + * multiplication, the high 32-bits are carried into the next step. + */ + rl.l.high = c = (u64)rl.l.high + rm.l.low + rn.l.low; + rh.l.low = c = (c >> 32) + rm.l.high + rn.l.high + rh.l.low; + rh.l.high = (c >> 32) + rh.l.high; + + /* + * The 128-bit result of the multiplication is in rl.ll and rh.ll, + * shift it right and throw away the high part of the result. + */ + if (shift == 0) + return rl.ll; + if (shift < 64) + return (rl.ll >> shift) | (rh.ll << (64 - shift)); + return rh.ll >> (shift & 63); +} +#endif /* mul_u64_u64_shr */ + +#endif + +#ifndef mul_u64_u32_div +static inline u64 mul_u64_u32_div(u64 a, u32 mul, u32 divisor) +{ + union { + u64 ll; + struct { +#ifdef __BIG_ENDIAN + u32 high, low; +#else + u32 low, high; +#endif + } l; + } u, rl, rh; + + u.ll = a; + rl.ll = mul_u32_u32(u.l.low, mul); + rh.ll = mul_u32_u32(u.l.high, mul) + rl.l.high; + + /* Bits 32-63 of the result will be in rh.l.low. */ + rl.l.high = do_div(rh.ll, divisor); + + /* Bits 0-31 of the result will be in rl.l.low. */ + do_div(rl.ll, divisor); + + rl.l.high = rh.l.low; + return rl.ll; +} +#endif /* mul_u64_u32_div */ + +u64 mul_u64_u64_div_u64(u64 a, u64 mul, u64 div); + +#define DIV64_U64_ROUND_UP(ll, d) \ + ({ u64 _tmp = (d); div64_u64((ll) + _tmp - 1, _tmp); }) + +/** + * DIV64_U64_ROUND_CLOSEST - unsigned 64bit divide with 64bit divisor rounded to nearest integer + * @dividend: unsigned 64bit dividend + * @divisor: unsigned 64bit divisor + * + * Divide unsigned 64bit dividend by unsigned 64bit divisor + * and round to closest integer. + * + * Return: dividend / divisor rounded to nearest integer + */ +#define DIV64_U64_ROUND_CLOSEST(dividend, divisor) \ + ({ u64 _tmp = (divisor); div64_u64((dividend) + _tmp / 2, _tmp); }) + +/* + * DIV_S64_ROUND_CLOSEST - signed 64bit divide with 32bit divisor rounded to nearest integer + * @dividend: signed 64bit dividend + * @divisor: signed 32bit divisor + * + * Divide signed 64bit dividend by signed 32bit divisor + * and round to closest integer. + * + * Return: dividend / divisor rounded to nearest integer + */ +#define DIV_S64_ROUND_CLOSEST(dividend, divisor)( \ +{ \ + s64 __x = (dividend); \ + s32 __d = (divisor); \ + ((__x > 0) == (__d > 0)) ? \ + div_s64((__x + (__d / 2)), __d) : \ + div_s64((__x - (__d / 2)), __d); \ +} \ +) +#endif /* _LINUX_MATH64_H */ |