diff options
Diffstat (limited to 'include/asm-generic/div64.h')
| -rw-r--r-- | include/asm-generic/div64.h | 24 |
1 files changed, 10 insertions, 14 deletions
diff --git a/include/asm-generic/div64.h b/include/asm-generic/div64.h index a3b98c86f077..13f5aa68a455 100644 --- a/include/asm-generic/div64.h +++ b/include/asm-generic/div64.h @@ -8,12 +8,14 @@ * Optimization for constant divisors on 32-bit machines: * Copyright (C) 2006-2015 Nicolas Pitre * - * The semantics of do_div() are: + * The semantics of do_div() is, in C++ notation, observing that the name + * is a function-like macro and the n parameter has the semantics of a C++ + * reference: * - * uint32_t do_div(uint64_t *n, uint32_t base) + * uint32_t do_div(uint64_t &n, uint32_t base) * { - * uint32_t remainder = *n % base; - * *n = *n / base; + * uint32_t remainder = n % base; + * n = n / base; * return remainder; * } * @@ -55,17 +57,11 @@ /* * If the divisor happens to be constant, we determine the appropriate * inverse at compile time to turn the division into a few inline - * multiplications which ought to be much faster. And yet only if compiling - * with a sufficiently recent gcc version to perform proper 64-bit constant - * propagation. + * multiplications which ought to be much faster. * * (It is unfortunate that gcc doesn't perform all this internally.) */ -#ifndef __div64_const32_is_OK -#define __div64_const32_is_OK (__GNUC__ >= 4) -#endif - #define __div64_const32(n, ___b) \ ({ \ /* \ @@ -228,8 +224,7 @@ extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor); is_power_of_2(__base)) { \ __rem = (n) & (__base - 1); \ (n) >>= ilog2(__base); \ - } else if (__div64_const32_is_OK && \ - __builtin_constant_p(__base) && \ + } else if (__builtin_constant_p(__base) && \ __base != 0) { \ uint32_t __res_lo, __n_lo = (n); \ (n) = __div64_const32(n, __base); \ @@ -239,8 +234,9 @@ extern uint32_t __div64_32(uint64_t *dividend, uint32_t divisor); } else if (likely(((n) >> 32) == 0)) { \ __rem = (uint32_t)(n) % __base; \ (n) = (uint32_t)(n) / __base; \ - } else \ + } else { \ __rem = __div64_32(&(n), __base); \ + } \ __rem; \ }) |