ppm_save() spends upwards of 50% of its time doing divisions. Replace them
with shifts.
Reviewed-by: Alon Levy <alevy@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
v = *(uint32_t *)d;
else
v = (uint32_t) (*(uint16_t *)d);
- r = ((v >> ds->pf.rshift) & ds->pf.rmax) * 256 /
- (ds->pf.rmax + 1);
- g = ((v >> ds->pf.gshift) & ds->pf.gmax) * 256 /
- (ds->pf.gmax + 1);
- b = ((v >> ds->pf.bshift) & ds->pf.bmax) * 256 /
- (ds->pf.bmax + 1);
+ /* Limited to 8 or fewer bits per channel: */
+ r = ((v >> ds->pf.rshift) & ds->pf.rmax) << (8 - ds->pf.rbits);
+ g = ((v >> ds->pf.gshift) & ds->pf.gmax) << (8 - ds->pf.gbits);
+ b = ((v >> ds->pf.bshift) & ds->pf.bmax) << (8 - ds->pf.bbits);
*pbuf++ = r;
*pbuf++ = g;
*pbuf++ = b;