Path: csiph.com!news.mixmin.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: D Finnigan Newsgroups: comp.sys.apple2 Subject: Re: How does the Apple IIGS emulate a =?UTF-8?B?SUllPw==?= Date: Mon, 19 Feb 2024 14:50:29 -0000 (UTC) Organization: Mac GUI Lines: 40 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Injection-Date: Mon, 19 Feb 2024 14:50:29 -0000 (UTC) Injection-Info: dont-email.me; posting-host="e20319294267193c0d1f966224696b3d"; logging-data="2030308"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/8KAg3ufBWCPke9Ny3rJFW" User-Agent: Mac GUI Usenet Cancel-Lock: sha1:DS87CxBARECiZjB7aWALPlUKZbM= In-Reply-To: Xref: csiph.com comp.sys.apple2:48863 Mitchell Spector wrote: > D Finnigan wrote: > >>From page 27 of the Custom ICs document: >> >>"The Mega II, shown in Figure 10, has virtually all the characteristics of >>an Apple II on a chip; it supports a slotted architecture and has built-in >>peripherals." >> >>-+- >> >>But I think it got corrupted into "a complete Apple IIe on a chip," which >>definitely isn't correct. > > The Mega II *is* a complete Apple IIe on a chip. It's just, for the > most > part, missing the CPU and ROM firmware. We don't need to argue this further, but in my opinion, if you state that it is missing the CPU and ROM firmware, then in my opinion you conclude that it is not a complete Apple IIe on a chip. :-) > > The Mega II apparently just sits in the IIGS performing unrelated I/O > tasks, NOT emulating an Apple IIe (the fact that it can, is wasted). A > part of it is used for providing classic Apple II text and video modes, > but > that may be it. Which again begs the question....if it isn't the Mega II, > what logic allows the Apple IIGS to emulate an Apple IIe? Part of the answer is the 8-bit mode in Mensch's 65C816, right? -- ]DF$ The New Apple II User's Guide: https://macgui.com/newa2guide/