cosmopolitan/dsp/core/c1331s.h

29 lines
788 B
C

#ifndef COSMOPOLITAN_DSP_CORE_C1331S_H_
#define COSMOPOLITAN_DSP_CORE_C1331S_H_
#if !(__ASSEMBLER__ + __LINKER__ + 0)
/**
* Byte sized kernel for resampling difference samples in half.
*
* @define (1*(a-128)+3*(a-128)+3*(a-128)+1*(a-128))/(1+3+3+1)+128
* @see C1331(), Y420CbCr2RgbScale()
*/
forceinline pureconst artificial signed char C1331S(signed char al,
signed char bl,
signed char cl,
signed char dl) {
short ax, bx;
bx = bl;
bx += cl;
bx *= 3;
ax = al;
ax += dl;
ax += bx;
ax += 4;
ax >>= 3;
return ax;
}
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
#endif /* COSMOPOLITAN_DSP_CORE_C1331S_H_ */