From mboxrd@z Thu Jan 1 00:00:00 1970 From: grog@lemis.com (Greg 'groggy' Lehey) Date: Wed, 4 May 2016 12:42:39 +1000 Subject: [TUHS] PDP-7 Unix Progress In-Reply-To: <20160504021240.GA29896@minnie.tuhs.org> References: <20160503072155.GA28307@minnie.tuhs.org> <57291BAF.6020507@aueb.gr> <20160504021240.GA29896@minnie.tuhs.org> Message-ID: <20160504024239.GI15924@eureka.lemis.com> On Wednesday, 4 May 2016 at 12:12:40 +1000, Warren Toomey wrote: > On Wed, May 04, 2016 at 12:44:15AM +0300, Diomidis Spinellis wrote: >> This would have found any code from the PDP-7 Unix that appeared in the >> First Edition. (I was hoping that some PDP-7 instruction sequences might be >> the same in PDP-11.) >> Unsurprisingly, nothing came out. > > No, the instruction set is completely different. The PDP-11 ISA is a > paradise compared to the spartan PDP-7 ISA. In case you're interested, I've located a reference manual at http://bitsavers.trailing-edge.com/pdf/dec/pdp7/F-75P_PDP7prelimUM_Dec64.pdf The instruction set is very reminiscent of the PDP-8, including the "operate" class "microcodding" instructions (starting with 7) and autoindexing via indirect access to locations 10 to 17. Even the mnemonics and the assembler syntax are very similar to the -8. Certainly the PDP-11 is an improvement, but there's something nostalgic about the -7 instruction set. Greg -- Sent from my desktop computer. Finger grog at FreeBSD.org for PGP public key. See complete headers for address and phone numbers. This message is digitally signed. If your Microsoft mail program reports problems, please read http://lemis.com/broken-MUA -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 181 bytes Desc: not available URL: