Path: utzoo!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!uunet!jarthur!nntp-server.caltech.edu!tybalt.caltech.edu!toddpw From: toddpw@tybalt.caltech.edu (Todd P. Whitesel) Newsgroups: comp.sys.apple2 Subject: Re: One Byte Memory Reads Message-ID: <1990Aug9.002639.3478@laguna.ccsf.caltech.edu> Date: 9 Aug 90 00:26:39 GMT References: <9008082141.AA25062@apple.com> Sender: news@laguna.ccsf.caltech.edu Organization: California Institute of Technology Lines: 17 MQUINN@UTCVM.BITNET writes: >Well, taking the GS's CPU out of 16-bit mode intl 8-bit mode is HOW you >take it out of native mode, so it's impossible to be in 8-bit mode and >native mode at the same time, although you can still keep the speed at Augh! Check before you post, please. You _can_ change the register sizes in native mode -- in fact, you have to, because reset puts the CPU in emulation mode and switching from emulation to native (CLC; XCE) doesn't change the register sizes at all; either you or the O/S has to do it. Once you are in native mode you can pick the accumulator size and the index registers size independently of each other (handy for I/O programming, when you have an 8 bit accumulator and 16 bit X and Y). Going back to emulation mode (SEC; XCE) forces the registers back to 8 bits each (as it should). Todd Whitesel toddpw @ tybalt.caltech.edu