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PSX GTE Use count_leading_zeros() & count_leading_ones() instead of counting manually. [smf]

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smf- 2018-09-24 14:59:08 +01:00
parent 7a6ba5c482
commit 80bc38691c
1 changed files with 2 additions and 20 deletions
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22
src/devices/cpu/psx/gte.cpp
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@ -145,24 +145,6 @@ static inline void ATTR_PRINTF(2,3) GTELOG( uint32_t pc, const char *a, ...) {}
#define CV2( n ) ( n < 3 ? m_cp2cr[ ( n << 3 ) + 6 ].sd : 0 ) #define CV2( n ) ( n < 3 ? m_cp2cr[ ( n << 3 ) + 6 ].sd : 0 )
#define CV3( n ) ( n < 3 ? m_cp2cr[ ( n << 3 ) + 7 ].sd : 0 ) #define CV3( n ) ( n < 3 ? m_cp2cr[ ( n << 3 ) + 7 ].sd : 0 )
static uint32_t gte_leadingzerocount( uint32_t lzcs )
{
uint32_t lzcr = 0;
if( ( lzcs & 0x80000000 ) == 0 )
{
lzcs = ~lzcs;
}
while( ( lzcs & 0x80000000 ) != 0 )
{
lzcr++;
lzcs <<= 1;
}
return lzcr;
}
int32_t gte::LIM( int32_t value, int32_t max, int32_t min, uint32_t flag ) int32_t gte::LIM( int32_t value, int32_t max, int32_t min, uint32_t flag )
{ {
if( value > max ) if( value > max )
@ -233,7 +215,7 @@ void gte::setcp2dr( uint32_t pc, int reg, uint32_t value )
break; break;
case 30: case 30:
LZCR = gte_leadingzerocount( value ); LZCR = (value & 0x80000000) == 0 ? count_leading_zeros(value) : count_leading_ones(value);
break; break;
case 31: case 31:
@ -332,7 +314,7 @@ static inline uint32_t gte_divide( uint16_t numerator, uint16_t denominator )
0x00 0x00
}; };
int shift = gte_leadingzerocount( denominator ) - 16; int shift = count_leading_zeros( denominator ) - 16;
int r1 = ( denominator << shift ) & 0x7fff; int r1 = ( denominator << shift ) & 0x7fff;
int r2 = table[ ( ( r1 + 0x40 ) >> 7 ) ] + 0x101; int r2 = table[ ( ( r1 + 0x40 ) >> 7 ) ] + 0x101;