Keep DAA! (was Re: 8086 bugs)

Chuck Guzis wrote: Anyone who wants to implement the nybble-to-hex functionality in a lot shorter space, maybe? :-) This: AND AL,0FH ADD AL,0F6H ADC AL,0AH ADD AL,0F6H ADC AL,0AH ADD AL,0F6H ADC AL,0AH ADD AL,0F6H ADC AL,0AH ADD AL,0F6H ADC AL,0AH ADD AL,0F6H ADC AL,0AH ADD AL,0F6H ADC AL,3AH ...is 30 bytes (accumulator forms included). This: mov bx,offset hextable and al,0fh xlat bx hextable: db '0123456789ABCDEF' ...is a total of 22 bytes including the hex table. (I love xlat.) But our DAA solution: and al,15 add al,90h daa adc al,40h daa ...is only 8 bytes. If DAA were slow, I'd say ditch it. But DAA is only 4 cycles and according to my real-world 8088 timings (slow night tonight), the DAA approach is only just a hair slower than the XLAT method. So I guess there *is* a need for DAA ;-) -- 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/