From d289816deba3432c0376716d4c6ed9c61eecdbd2 Mon Sep 17 00:00:00 2001 From: maedhros Date: Sun, 14 Jan 2007 19:06:11 +0000 Subject: (svn r8123) -Fix (r117): FindFirstBit now really returns the first bit. Fixes bug FS#538. --- src/misc.cpp | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/src/misc.cpp b/src/misc.cpp index 39714bb55..921e267b1 100644 --- a/src/misc.cpp +++ b/src/misc.cpp @@ -266,16 +266,18 @@ void InitializeLandscapeVariables(bool only_constants) int FindFirstBit(uint32 value) { - // This is much faster than the one that was before here. - // Created by Darkvater.. blame him if it is wrong ;) - // Btw, the macro FINDFIRSTBIT is better to use when your value is - // not more than 128. + // The macro FIND_FIRST_BIT is better to use when your value is + // not more than 128. byte i = 0; - if (value & 0xffff0000) { value >>= 16; i += 16; } - if (value & 0x0000ff00) { value >>= 8; i += 8; } - if (value & 0x000000f0) { value >>= 4; i += 4; } - if (value & 0x0000000c) { value >>= 2; i += 2; } - if (value & 0x00000002) { i += 1; } + + if (value == 0) return 0; + + if ((value & 0x0000ffff) == 0) { value >>= 16; i += 16; } + if ((value & 0x000000ff) == 0) { value >>= 8; i += 8; } + if ((value & 0x0000000f) == 0) { value >>= 4; i += 4; } + if ((value & 0x00000003) == 0) { value >>= 2; i += 2; } + if ((value & 0x00000001) == 0) { i += 1; } + return i; } -- cgit v1.2.3-70-g09d2