ref: 824606680e4c4dc6b4ddb10cba2d08b2f81f8e25
dir: /span.c/
#include "quakedef.h"
void
dospan(pixel_t *pdest, pixel_t *pbase, int s, int t, int sstep, int tstep, int spancount, int cachewidth)
{
do{
*pdest++ = pbase[(s >> 16) + (t >> 16) * cachewidth];
s += sstep;
t += tstep;
}while(--spancount);
}