From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 Received: (qmail 24997 invoked from network); 25 Jul 2023 07:44:08 -0000 Received: from minnie.tuhs.org (2600:3c01:e000:146::1) by inbox.vuxu.org with ESMTPUTF8; 25 Jul 2023 07:44:08 -0000 Received: from minnie.tuhs.org (localhost [IPv6:::1]) by minnie.tuhs.org (Postfix) with ESMTP id 76D2C42A3D; Tue, 25 Jul 2023 17:44:04 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tuhs.org; s=dkim; t=1690271044; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type:list-id:list-help:list-owner: list-unsubscribe:list-subscribe:list-post; bh=Fg3MpZlZmfDPVVG9c6yS7hcUh8myNUCzR8xtAd7HedY=; b=jMexHiMt+JwPQLjBKnIvyel7QRBQvoX3ZrXffdFd5XKnasVVLun0OrArHmt0Yamh/DGddy Uwxwtu81DHjkIHPBPDVvAr250SO1iiMz1GkzDRzvkEnhP3i9AB45s52oMgFFvwf/Z9gE3l tWAAJdGBo8sTxXCap8yiVRJJ3YD1jr8= Received: by minnie.tuhs.org (Postfix, from userid 1000) id 5DDC142A06; Tue, 25 Jul 2023 17:41:44 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tuhs.org; s=dkim; t=1690270904; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type; bh=Fg3MpZlZmfDPVVG9c6yS7hcUh8myNUCzR8xtAd7HedY=; b=sENKRvBDSO7Iaar9Zlyqgl9p0Nr9qVHSeKx5b27PRys6yWBYfU0e2+mrii1mz4R+/JLPad gAXaoGcVvTcdRed6lgkbWdqfd2cnd2NsUxVkzz4wrxo/PI4Ymxz/4sv8dvbOMqV6YFRBCM NgNxlUTK9eSGMHCiUaMMRZElaP1NR7A= Date: Tue, 25 Jul 2023 17:41:44 +1000 To: coff@tuhs.org Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-MailFrom: wkt@tuhs.org X-Mailman-Rule-Hits: nonmember-moderation X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation Message-ID-Hash: VXFN6BEBLJIFBERRXE7545QQBWMGFVTC X-Message-ID-Hash: VXFN6BEBLJIFBERRXE7545QQBWMGFVTC X-Mailman-Approved-At: Tue, 25 Jul 2023 17:43:58 +1000 X-Mailman-Version: 3.3.6b1 Precedence: list Subject: [COFF] Wanted: 16-bit big-endian Unix-like environment and/or libc List-Id: Computer Old Farts Forum Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: From: Warren Toomey via COFF Reply-To: Warren Toomey Hi all, I'm looking for a 16-bit big-endian Unix-like development environment with a reasonably new C compiler and a symbolic debugger. And/or, a libc with source code suitable for a 16-bit big-endian environment. Rationale: I've designed and built a 6809 single board computer (SBC) with 8K ROM, 2K I/O space for a UART and block storage, and 56K RAM. It's a big-endian platform and the C compiler has 16-bit ints by default. I've been able to take the filesystem code from XV6 and get it to fit into the ROM with a hundred bytes spare. The available Unix-like system calls are: dup, read, write, close, fstat, link, unlink, open, mkdir, chdir, exit, spawn and the spawn is like exec(). There is no fork() and no multitasking. I've got many of the existing XV6 userland programs to run along with a small shell that can do basic redirection. Now I'm trying to bring up a libc on the platform. I'm currently trying the libc from FUZIX but I'm not wedded to it, so alternative libc recommendations are most welcome. There's no debugging environment on this SBC. I do have a simulator that matches the hardware, but I can only breakpoint at addresses and single-step instructions. It makes debugging pretty tedious! So I was thinking of using an existing Unix-like platform to bring up the libc. That way, if there are bugs, I can use an existing symbolic debugger on the platform. I could use 2.11BSD as the dev platform but it's little-endian; I'm worried that there might be endian issues that stop me finding bugs that will arise on the 16-bit 6809 platform. As for which libc: I looked at the 2.11BSD libc/include and there's so much stuff I don't need (networking etc.) that it's hard to winnow down to just what I need. The FUZIX libc looks good. I just came across Elks and that might be a possible alternative. Are there others to consider? Anyway, thanks in advance for your suggestions. Cheers, Warren References: XV6: https://github.com/mit-pdos/xv6-public FUXIZ: https://github.com/EtchedPixels/FUZIX/tree/master/Library Elks: https://github.com/jbruchon/elks/tree/master/libc