On Wednesday 05 May 2004 21:54, Jeff Ratliff wrote: >On Wed, May 05, 2004 at 11:11:05AM -0400, Gene Heskett wrote: >> Unforch Rodney Zacks left a couple of errors in that tome that >> you'll probably discover when you do your first or second assembly >> or machine code routine based on looking up the hex values in that >> book and entering them with the monitor. Been there, done that. >> >> Rodney's stuff for other platforms was more accurate. > >I seem to remember there where some important things in there that >didn't quite match up. Mine was actually misprinted and had one of > the later chapters printed twice. Whatever was in the missing > chapter must not have been that important. > >It taught me binary and hex and basics of CPU architecture, though. >That Z-80 was a hot little chip. Too bad IBM went with Intel > instead. Imagine a Zylog based IBM PC running CPM-86 in 1981! > >OK, I better shut up now. It wasn't that bad if you had a good one, I fought with one for weeks that would only execute the $eb command on alternate thursdays when it was raining. $eb is the swap register sets command. My biggest disappointment in that chip was the lack of conditional long jumps, you had to jump +126-128 for an address range, so you always wound up with a long jump table someplace in a page of code that had to be short jumped over by the code that was actually running. Made your code look like it was laid out by a drunken rattlesnake od'd on uppers. Moto's 6809 was a much smarter chip, and the hitachi replacement 63C09 they can't talk about in fact has the microcode map filled up completely. How about 16x16 bit multiplies with a 32 bit result in 25 clocks, or a 32/16 divide with 16 bit remainder and dividend in 39 clocks worst case. Also 32 bit loads and stores. Bear in mind its an 8 bit data buss chip we're talking about here. Oh, almost forgot, it also does PIC, something that was a totally foreign concept over at zilog. Really, no valid comparison can be made between the two chips that will make the look Z-80 superior. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) 99.22% setiathome rank, not too shabby for a WV hillbilly Yahoo.com attorneys please note, additions to this message by Gene Heskett are: Copyright 2004 by Maurice Eugene Heskett, all rights reserved.
