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(svn r11383) -Codechange: fixed all the mess around KillFirstBit (tnx to Rubidium and skidd13)

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truelight
2007-11-04 23:06:39 +00:00
parent 69b1d97c03
commit 4b8aaa994c
10 changed files with 22 additions and 41 deletions
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20
src/macros.h
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@@ -354,7 +354,7 @@ template<typename T> static inline T TOGGLEBIT(T& x, const uint8 y)
*/
#define IS_CUSTOM_SPRITE(sprite) ((sprite) >= SPR_SIGNALS_BASE)
extern const byte _ffb_64[128];
extern const byte _ffb_64[64];
/**
* Returns the first occure of a bit in a 6-bit value (from right).
@@ -368,17 +368,6 @@ extern const byte _ffb_64[128];
*/
#define FIND_FIRST_BIT(x) _ffb_64[(x)]
/**
* Returns a value with the first occured of a bit set to zero.
*
* Returns x with the first bit from LSB that is not zero set
* to zero. So, 110100 returns 110000, 000001 returns 000000, etc.
*
* @param x The value to returned a new value
* @return The value which the first bit is set to zero
*/
#define KILL_FIRST_BIT(x) _ffb_64[(x) + 64]
/**
* Finds the position of the first bit in an integer.
*
@@ -416,14 +405,15 @@ Faster ( or at least cleaner ) implementation below?
* Clear the first bit in an integer.
*
* This function returns a value where the first bit (from LSB)
* is cleared. This function checks only the bits of 0x3F3F!
* is cleared.
* So, 110100 returns 110000, 000001 returns 000000, etc.
*
* @param value The value to clear the first bit
* @return The new value with the first bit cleared
*/
static inline uint KillFirstBit2x64(uint value)
template<typename T> static inline T KillFirstBit(T value)
{
return value &= (uint)(value - 1) | 0x3FFFC0C0;
return value &= (T)(value - 1);
}
/**