Path: ...!weretis.net!feeder8.news.weretis.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Stephen Fuld Newsgroups: comp.arch Subject: Re: is Vax addressing sane today Date: Wed, 25 Sep 2024 12:30:02 -0700 Organization: A noiseless patient Spider Lines: 28 Message-ID: References: <2024Sep10.094353@mips.complang.tuwien.ac.at> <3b7a257101d09e1995314aadace0e14f@www.novabbs.org> <93cbf6da3d60952471668b3cc5dc61f9@www.novabbs.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Injection-Date: Wed, 25 Sep 2024 21:30:02 +0200 (CEST) Injection-Info: dont-email.me; posting-host="712df838b41f4ba9af5c9561f5afb4e2"; logging-data="2740622"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+DLK5aJli6aCRrqbVmXSnhhE7+r5oOvKo=" User-Agent: Mozilla Thunderbird Cancel-Lock: sha1:p837SWbVvgruoqdEae2mG6mGGEM= In-Reply-To: <93cbf6da3d60952471668b3cc5dc61f9@www.novabbs.org> Content-Language: en-US Bytes: 2256 On 9/24/2024 10:57 AM, MitchAlsup1 wrote: > On Tue, 24 Sep 2024 17:06:27 +0000, Stephen Fuld wrote: > >> On 9/23/2024 11:02 PM, Terje Mathisen wrote: >> >> snip >> >>> Maybe all add/sub/etc opcodes that are immediately followed by an INTO >>> could be fused into a single ADDO/SUBO/etc version that takes zero extra >>> cycles as long as the trap part isn't hit? >> >> If you are going to do that, why not make it an optional prefix byte? >> That way, no fusion needed, no extra cycles, yet the same amount of code >> space. > > Realistically, what is the difference if INTO is a prefix > byte or a postfix byte ? Of course, IANAHG, but my guess was that not having to do instruction fusion was worth something, and my suggestion has zero cost. If this is wrong, then there is no difference. -- - Stephen Fuld (e-mail address disguised to prevent spam)