diff options
Diffstat (limited to 'lib/reciprocal_div.c')
-rw-r--r-- | lib/reciprocal_div.c | 69 |
1 files changed, 0 insertions, 69 deletions
diff --git a/lib/reciprocal_div.c b/lib/reciprocal_div.c deleted file mode 100644 index bf043258fa00..000000000000 --- a/lib/reciprocal_div.c +++ /dev/null @@ -1,69 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -#include <linux/bug.h> -#include <linux/kernel.h> -#include <asm/div64.h> -#include <linux/reciprocal_div.h> -#include <linux/export.h> - -/* - * For a description of the algorithm please have a look at - * include/linux/reciprocal_div.h - */ - -struct reciprocal_value reciprocal_value(u32 d) -{ - struct reciprocal_value R; - u64 m; - int l; - - l = fls(d - 1); - m = ((1ULL << 32) * ((1ULL << l) - d)); - do_div(m, d); - ++m; - R.m = (u32)m; - R.sh1 = min(l, 1); - R.sh2 = max(l - 1, 0); - - return R; -} -EXPORT_SYMBOL(reciprocal_value); - -struct reciprocal_value_adv reciprocal_value_adv(u32 d, u8 prec) -{ - struct reciprocal_value_adv R; - u32 l, post_shift; - u64 mhigh, mlow; - - /* ceil(log2(d)) */ - l = fls(d - 1); - /* NOTE: mlow/mhigh could overflow u64 when l == 32. This case needs to - * be handled before calling "reciprocal_value_adv", please see the - * comment at include/linux/reciprocal_div.h. - */ - WARN(l == 32, - "ceil(log2(0x%08x)) == 32, %s doesn't support such divisor", - d, __func__); - post_shift = l; - mlow = 1ULL << (32 + l); - do_div(mlow, d); - mhigh = (1ULL << (32 + l)) + (1ULL << (32 + l - prec)); - do_div(mhigh, d); - - for (; post_shift > 0; post_shift--) { - u64 lo = mlow >> 1, hi = mhigh >> 1; - - if (lo >= hi) - break; - - mlow = lo; - mhigh = hi; - } - - R.m = (u32)mhigh; - R.sh = post_shift; - R.exp = l; - R.is_wide_m = mhigh > U32_MAX; - - return R; -} -EXPORT_SYMBOL(reciprocal_value_adv); |