4–154 Alpha Architecture Handbook
4.13.2 Pixel Error
Format:
Operation:
temp = 0
FOR i FROM 0 TO 7
IF { Rav<i*8+7:i*8> GEU Rbv<i*8+7:i*8>} THEN
temp ← temp + (Rav<i*8+7:i*8> - Rbv<i*8+7:i*8>)
ELSE
temp ← temp + (Rbv<i*8+7:i*8> - Rav<i*8+7:i*8>)
END
Rc ← temp
Exceptions:
Instruction mnemonics:
Qualifiers:
Description:
The absolute value of the difference between each of the bytes in Ra and Rb is calculated. The
sum of the resulting bytes is written to Rc.
PERR Ra.rq,Rb.rq,Rc.wq
! Operate Format
None
PERR Pixel Error
None