Legacy apps in Windows/OS X was Re: Old MS-DOS & Win Software

woodelf wrote: 4 measly bytes: Hey, better to have 4 bytes than none at all. As for 3-4 bytes long, remember, the Bus Interface Unit can be fetching at the same time an instruction is executing, so that's where you go break out the Zen timer. There are gray areas, such as: Which is faster on 8088? A or B? A: SHL AX,1 B: MOV CL,3 SHL AX,1 SHL AX,CL SHL AX,1 A is faster. Now add another shift: A: SHL AX,1 B: MOV CL,4 SHL AX,1 SHL AX,CL SHL AX,1 SHL AX,1 B (and all subsequent increases in operand) is faster. So that's the 10% I was mentioning where you just have to time it to find out whether or not the BIU or EU won the race. Same goes for multiple INCs vs. ADD reg,immediate vs. ADD reg,reg vs. ADD accum.,reg (ADDing with AX/AL is smaller/faster than with other registers) -- Jim Leonard (trixter at oldskool.org) http://www.oldskool.org/ Want to help an ambitious games project? http://www.mobygames.com/ Or check out some trippy MindCandy at http://www.mindcandydvd.com/