Path: ...!weretis.net!feeder9.news.weretis.net!news.nk.ca!rocksolid2!i2pn2.org!.POSTED!not-for-mail From: mitchalsup@aol.com (MitchAlsup1) Newsgroups: comp.arch Subject: Re: number of registers Date: Tue, 20 Aug 2024 20:59:28 +0000 Organization: Rocksolid Light Message-ID: <48438024ccdbcc373e4cfa51d18066f5@www.novabbs.org> References: <38055f09c5d32ab77b9e3f1c7b979fb4@www.novabbs.org> <2024Aug20.090149@mips.complang.tuwien.ac.at> <20240820204050.00003d56@yahoo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Info: i2pn2.org; logging-data="3272336"; mail-complaints-to="usenet@i2pn2.org"; posting-account="65wTazMNTleAJDh/pRqmKE7ADni/0wesT78+pyiDW8A"; User-Agent: Rocksolid Light X-Spam-Checker-Version: SpamAssassin 4.0.0 X-Rslight-Site: $2y$10$YukRRrto9Xv0wKozEZ8vx.KYJgMIdpU/wMNM1qB9xd6wD7ekWnoKG X-Rslight-Posting-User: ac58ceb75ea22753186dae54d967fed894c3dce8 Bytes: 2094 Lines: 20 On Tue, 20 Aug 2024 17:40:50 +0000, Michael S wrote: > On Tue, 20 Aug 2024 16:40:06 +0000 > mitchalsup@aol.com (MitchAlsup1) wrote: > >> >> and you may have >> several of these in a local sequence of code. ... > > No, you can not have several. It's always one then another one then yet > another one etc... Each one can reuse the same temporary register. The point is that the cost of not getting allocated into a register is vastly lower--the count of instructions remains 1 while the latency increases. That increase in latency does not hurt those use once/seldom variables. The the examples cited, the lack of register allocation triples the instruction count due to lack of LD-OP and LD-OP-ST. The register count I stated is how many registers would a non-LD-OP machine need to break even on the instruction count.