From e7fa78d60bb78d3752fd1735d91f36641375c490 Mon Sep 17 00:00:00 2001 From: tron Date: Sun, 17 Jul 2005 09:41:28 +0000 Subject: (svn r2596) Add macros ROL and ROR to ROtate values Left/Right. Also shorten the parameter names for GB and SB to increase readability --- macros.h | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) (limited to 'macros.h') diff --git a/macros.h b/macros.h index b5c4d11d8..28b61c308 100644 --- a/macros.h +++ b/macros.h @@ -153,9 +153,16 @@ static inline void swap_tile(TileIndex *a, TileIndex *b) { TileIndex t = *a; *a } #endif -// Fetch count bits starting at bit start from value -#define GB(value, start, count) (((value) >> (start)) & ((1 << (count)) - 1)) -// Set count bits in value starting at bit start to data -#define SB(value, start, count, data) ((value) = ((value) & ~(((1 << (count)) - 1) << (start))) | ((data) << (start))) +/// Fetch n bits starting at bit s from x +#define GB(x, s, n) (((x) >> (s)) & ((1 << (n)) - 1)) +/// Set n bits in x starting at bit s to d +#define SB(x, s, n, d) ((x) = ((x) & ~(((1 << (n)) - 1) << (s))) | ((d) << (s))) + +/** + * ROtate x Left/Right by n (must be >= 0) + * @note Assumes a byte has 8 bits + */ +#define ROL(x, n) ((x) << (n) | (x) >> (sizeof(x) * 8 - (n))) +#define ROR(x, n) ((x) >> (n) | (x) << (sizeof(x) * 8 - (n))) #endif /* MACROS_H */ -- cgit v1.2.3-54-g00ecf