8088 vs. 80c88

On 22 Feb 2009 at 18:54, bfranchuk at jetnet.ab.ca wrote: Here's the one with JRT Pascal (IIRC): LXI SP,LABELX CALL LABELX LABELX: ... RET crashes and burns on a V20. Runs fine on an 8080/Z80. I may not have it exactly--this was over 20 years ago and it's going to take some digging to find my paperwork on the V20. Until then, you'll have to rely on my ever-more-tenuous memory it or try it for yourself. V20 emulation mode was enough of a problem that we eventually disabled it in 22NICE. x86 machines were getting powerful enough that software emulation was faster anyway. We could also do things in software emulation that we couldn't do in V20 mode, such as trap I/O accesses and redirect them to user-written servicers. My contact at NEC Natick was Rich Naro and he indicated that 8080 emulation mode was very low on the "things to be fixed" list in the V- series chips. There were also some very strange behavior when an 8087 was included into the mix. Cheers, Chuck