From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from resqmta-po-07v.sys.comcast.net (resqmta-po-07v.sys.comcast.net [IPv6:2001:558:fe16:19:96:114:154:166]) by sourceware.org (Postfix) with ESMTPS id 917D63861802 for ; Tue, 6 Jul 2021 23:50:07 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 917D63861802 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=comcast.net Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=comcast.net Received: from resomta-po-14v.sys.comcast.net ([96.114.154.238]) by resqmta-po-07v.sys.comcast.net with ESMTP id 0uSjmxpuKiCWI0upJm1DdK; Tue, 06 Jul 2021 23:50:05 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=20190202a; t=1625615405; bh=ny9L86uxUZnL02MmlZ2QIVRokGRKYXzX1Jx+NdROnMc=; h=Received:Received:Content-Type:Mime-Version:Subject:From:Date: Message-Id:To; b=yWrwWzqgDDLKtlmscJESUZPhN4p+7n6puGWvQZSH7uv4l+E0e7Xnv0DNmIHkjt+f/ we6zklB6yzBX/DHSAwwsNUWxu1i6/UvKImqOo5m//758Jr6IYUbgoyCSo9TQYoBWC4 sTjOG8s3+5VXsiIuyJUcw56sYDvmLdyvQKLK0F3UHG3ahsKqo2GO2DVhCW9n1MbkPF 0QVCe7E4+NCYRD1CYyE2+BWH09Ji6NbOEHfN1p76iDfSFGZ5sQtr3BNz8jT5ij7yvC b9PmaiZ10h7JWO3CniP0zBJAaJLAox/1CPSymNgnBKi+jYGI9bnLdEI68TUZgxLZbU eVrD3ec5yFUpw== Received: from pkoning.akdesign.com ([73.60.223.101]) by resomta-po-14v.sys.comcast.net with ESMTPSA id 0upEmvk6WNzkk0upGm991K; Tue, 06 Jul 2021 23:50:05 +0000 X-Xfinity-VAAS: gggruggvucftvghtrhhoucdtuddrgedvtddrtddugddukecutefuodetggdotefrodftvfcurfhrohhfihhlvgemucevohhmtggrshhtqdftvghsihdpqfgfvfdppffquffrtefokffrnecuuegrihhlohhuthemuceftddunecunecujfgurheptggguffhjgffgffkfhfvofesthhqmhdthhdtvdenucfhrhhomheprfgruhhlucfmohhnihhnghcuoehprghulhhkohhnihhnghestghomhgtrghsthdrnhgvtheqnecuggftrfgrthhtvghrnhepgfeuiefffeelveevkeeitddtfeejgfehudeuffelueetkeevhedtleefgffghedvnecuffhomhgrihhnpehmrghlsggrnhdruggvnecukfhppeejfedriedtrddvvdefrddutddunecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehhvghlohepphhkohhnihhnghdrrghkuggvshhighhnrdgtohhmpdhinhgvthepjeefrdeitddrvddvfedruddtuddpmhgrihhlfhhrohhmpehprghulhhkohhnihhnghestghomhgtrghsthdrnhgvthdprhgtphhtthhopehjohgvlhesrhhtvghmshdrohhrghdprhgtphhtthhopegvlhhijhgrgigrphhpshesghhmrghilhdrtghomhdprhgtphhtthhopehnvgiflhhisgesshhouhhrtggvfigrrhgvrdhorhhg X-Xfinity-VMeta: sc=0.00;st=legit Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.21\)) Subject: Re: Help porting newlib to a new CPU architecture (sorta) From: Paul Koning In-Reply-To: Date: Tue, 6 Jul 2021 19:50:00 -0400 Cc: ElijaxApps , Newlib Content-Transfer-Encoding: quoted-printable Message-Id: <9F9C0A22-1CCA-47F8-8C19-F44ED4B47A8F@comcast.net> References: To: joel@rtems.org X-Mailer: Apple Mail (2.3445.104.21) X-Spam-Status: No, score=-3.0 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, JMQ_SPF_NEUTRAL, RCVD_IN_DNSWL_LOW, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: newlib@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Newlib mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 06 Jul 2021 23:50:08 -0000 > On Jul 6, 2021, at 6:00 PM, Joel Sherrill wrote: >=20 > I think you might get some ideas from the old m6809 port of gcc >=20 > http://vectrexc.malban.de/documentation/gcc-6809-documentation >=20 > That was an 8 bit CPU with only 64k memory space if I remember = everything > correctly. pdp11 also has 64k of address space, and the current gcc still supports = it. > I think given an add with carry, gcc can be taught to use 8 bit = operations > in sequence on larger types. I recall seeing this on the h8 or avr. pdp11 also, for 32 or 64 bit integers given 16 bit arithmetic. You = don't actually need add with carry, but having one makes the code more = compact. I think gcc core will do that flavor if the target code = doesn't teach it the more efficient way (which is easy to do). paul