On 02/09/2018 04:18 PM, Sean Conner wrote: > It was thus said that the Great allison via cctalk once stated: >> The industry was loaded with that the 6502 series also had that going on >> as well as the 6809 and others. > Do you have any information about undocumented opcodes for the 6809? > > -spc Not a processor I use much bt there is a version of the 6809 that has additional modes. Thats the Hitachi 63b09 wich is 6809E compatable save for it has an extended mode and more registers.
I use that as an example of compatibility or extensions another more familiar is the NEC V20 fits in the 8088 socket but has enhanced performance and native 8080 emulation mode. Allison