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| author | Bjoern A. Zeeb <bz@FreeBSD.org> | 2023-05-16 20:55:00 +0000 |
|---|---|---|
| committer | Bjoern A. Zeeb <bz@FreeBSD.org> | 2023-11-29 16:36:04 +0000 |
| commit | f0d33323feab22b2550437132b8ee89f2086b310 (patch) | |
| tree | a847d777ff0f3349d5282bfe22e8668737094cd1 | |
| parent | 4317faf44d434f514487c1c1c54b760971ed6f9c (diff) | |
| download | src-f0d33323feab22b2550437132b8ee89f2086b310.tar.gz src-f0d33323feab22b2550437132b8ee89f2086b310.zip | |
LinuxKPI: implement mul_u64_u64_div_u64()
Implement mul_u64_u64_div_u64() for an updated iwlwifi driver (though
we do not yet use it there; it is used for in-kernel ptp on wifi).
Sponsored by: The FreeBSD Foundation
(cherry picked from commit b80ea452375f52a3ab7d82a9aef10da0d89985d9)
Unbalanced parentheses broke the build; re-balance.
Fixes: b80ea452375f ("LinuxKPI: implement mul_u64_u64_div_u64()")
(cherry picked from commit dabbbebcb0f5ced163454cd08b78e551b4a365b5)
linuxkpi math: fix kassert in math64.h
Include <sys/systm.h> in math64.h, so that KASSERT and bool are
defined, to allow compilation to succeed after
b80ea452375f52a3ab7d82a9aef10da0d89985d9 and dabbbebcb0f5...
(cherry picked from commit b6a61d6836d90ff2756d804eb981a02b0828f496)
| -rw-r--r-- | sys/compat/linuxkpi/common/include/linux/math64.h | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/sys/compat/linuxkpi/common/include/linux/math64.h b/sys/compat/linuxkpi/common/include/linux/math64.h index 1b00fd71e69f..cae5e30b08df 100644 --- a/sys/compat/linuxkpi/common/include/linux/math64.h +++ b/sys/compat/linuxkpi/common/include/linux/math64.h @@ -29,6 +29,7 @@ #define _LINUXKPI_LINUX_MATH64_H #include <sys/stdint.h> +#include <sys/systm.h> #define do_div(n, base) ({ \ uint32_t __base = (base); \ @@ -107,6 +108,54 @@ mul_u64_u32_div(uint64_t x, uint32_t y, uint32_t div) } static inline uint64_t +mul_u64_u64_div_u64(uint64_t x, uint64_t y, uint64_t z) +{ + uint64_t res, rem; + uint64_t x1, y1, y1z; + + res = rem = 0; + x1 = x; + y1z = y / z; + y1 = y - y1z * z; + + /* + * INVARIANT: x * y = res * z + rem + (y1 + y1z * z) * x1 + * INVARIANT: y1 < z + * INVARIANT: rem < z + */ + while (x1 > 0) { + /* Handle low bit. */ + if (x1 & 1) { + x1 &= ~1; + res += y1z; + rem += y1; + if ((rem < y1) || (rem >= z)) { + res += 1; + rem -= z; + } + } + + /* Shift x1 right and (y1 + y1z * z) left */ + x1 >>= 1; + if ((y1 * 2 < y1) || (y1 * 2 >= z)) { + y1z = y1z * 2 + 1; + y1 = y1 * 2 - z; + } else { + y1z *= 2; + y1 *= 2; + } + } + + KASSERT(res * z + rem == x * y, ("%s: res %ju * z %ju + rem %ju != " + "x %ju * y %ju", __func__, (uintmax_t)res, (uintmax_t)z, + (uintmax_t)rem, (uintmax_t)x, (uintmax_t)y)); + KASSERT(rem < z, ("%s: rem %ju >= z %ju\n", __func__, + (uintmax_t)rem, (uintmax_t)z)); + + return (res); +} + +static inline uint64_t mul_u64_u32_shr(uint64_t x, uint32_t y, unsigned int shift) { uint32_t hi, lo; |