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gpu: use ilog2 instead of custom int-to-float messing around (backported from Qualcomm's GSL)

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This commit is contained in:
Matt Sealey
2011-07-28 19:02:50 -05:00
parent 4ffd877f1b
commit 8bf0ded04f
1 changed files with 12 additions and 18 deletions
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30
drivers/mxc/amd-gpu/common/gsl_drawctxt.c
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@@ -152,32 +152,26 @@ typedef struct
}
ctx_t;
//////////////////////////////////////////////////////////////////////////////
// Helper function to calculate IEEE754 single precision float values without FPU
//////////////////////////////////////////////////////////////////////////////
/* Helper function to calculate IEEE754 single precision float values
* without FPU
*/
unsigned int uint2float( unsigned int uintval )
{
unsigned int exp = 0;
unsigned int frac = 0;
unsigned int u = uintval;
unsigned int exp, frac = 0;
// Handle zero separately
if( uintval == 0 ) return 0;
if( uintval == 0 )
return 0;
// Find log2 of u
if(u>=0x10000) { exp+=16; u>>=16; }
if(u>=0x100 ) { exp+=8; u>>=8; }
if(u>=0x10 ) { exp+=4; u>>=4; }
if(u>=0x4 ) { exp+=2; u>>=2; }
if(u>=0x2 ) { exp+=1; u>>=1; }
exp = ilog2(uintval);
// Calculate fraction
frac = ( uintval & ( ~( 1 << exp ) ) ) << ( 23 - exp );
/* Calculate fraction */
if (23 > exp)
frac = ( uintval & ( ~( 1 << exp ) ) ) << ( 23 - exp );
// Exp is biased by 127 and shifted 23 bits
/* Exp is biased by 127 and shifted 23 bits */
exp = ( exp + 127 ) << 23;
return ( exp | frac );
return exp | frac;
}
//////////////////////////////////////////////////////////////////////////////