Re: PDP-11 Newbie Alert --- (gotta start somewhere)

On Apr 14, 14:44, Robert D. Keys wrote: Yes, you want one of the emulator packages and a disk image for that. BTW, the disk images I've seen don't have man pages, so you may want to download those separately. There are so many permutations, it's hard to make a list. There are two general classes of PDP-11, QBus and Unibus. Most even-numbered models are Unibus, most odd-numbered models are QBus (but not all). QBus machines tend to be smaller. As to operating system versions, 2.11BSD needs at least an 11/73 or 83 to run, as it needs memory management with separate address spaces for instructions and data. 7th Edition will also run on those machines, and if the kernel is suitably compiled, will also run on smaller machines such as 11/23s, which are quite common. Early versions will run on a whole range of models. Whatever you get, you'll need a processor (which might be a single card or as many as ten), memory (256K will do fine for 7th Edition, but more is better), at least one serial line unit for a terminal (or PC with terminal emulation software), and a disk controller with a suitable hard disk. Here again there are lots of possibilities, you want at least 10MB for 7th Edition and a lot more for BSD. Others may wish to expand on what I've written. Personally, I'd go see what you can find, describe it to the list, and wait for the 101 pieces of advice you'll get from all of us about its suitability/desirability :-) -- Pete Peter Turnbull Dept. of Computer Science University of York Received: (from major@localhost) by minnie.cs.adfa.oz.au (8.8.5/8.8.5) id NAA02452 for pups-liszt; Wed, 15 Apr 1998 13:09:43 +1000 (EST) X-Authentication-Warning: minnie.cs.adfa.oz.au: major set sender to owner-pups(a)minnie.cs.adfa.oz.au using -f Received: from renoir.op.net (root(a)renoir.op.net [209.152.193.4]) by minnie.cs.adfa.oz.au (8.8.5/8.8.5) with ESMTP id NAA02444 for <pups(a)minnie.cs.adfa.oz.au>au>; Wed, 15 Apr 1998 13:09:37 +1000 (EST) Received: from goppelt.op.net (d-phlarc1-00.ppp.op.net [209.152.199.64]) by renoir.op.net (o1/$Revision: 1.16 $) with SMTP id XAA00267 for <pups(a)minnie.cs.adfa.oz.au>au>; Tue, 14 Apr 1998 23:09:25 -0400 (EDT) Message-Id: <199804150309.XAA00267(a)renoir.op.net> Comments: Authenticated sender is <edgee(a)cyberpass.net> From: "Ed G." <edgee(a)cyberpass.net> To: pups(a)minnie.cs.adfa.oz.au Date: Tue, 14 Apr 1998 23:09:26 -0400 MIME-Version: 1.0 Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7BIT Subject: PDP-11 Addressing Modes Reply-to: edgee(a)cyberpass.net X-mailer: Pegasus Mail for Win32 (v2.54) Sender: owner-pups(a)minnie.cs.adfa.oz.au Precedence: bulk The first line of chapter on addressing modes in the *processor handbook* states: "In the PDP-11 family, all operand addressing is accomplished through the eight general purpose registers." If I understand correctly, even things like immediate operands and addresses are represented as an addressing mode of a register, namely the PC. I think this is quite cool. What do people here on the list think of the flexibility and generality of the PDP-11's addressing modes? Is this a well thought out architecture in your view? How are the PDP-11's addressing modes better or worse than those of other processors, past and present? Received: (from major@localhost) by minnie.cs.adfa.oz.au (8.8.5/8.8.5) id NAA02467 for pups-liszt; Wed, 15 Apr 1998 13:09:51 +1000 (EST) X-Authentication-Warning: minnie.cs.adfa.oz.au: major set sender to owner-pups(a)minnie.cs.adfa.oz.au using -f Received: from renoir.op.net (root(a)renoir.op.net [209.152.193.4]) by minnie.cs.adfa.oz.au (8.8.5/8.8.5) with ESMTP id NAA02451 for <pups(a)minnie.cs.adfa.oz.au>au>; Wed, 15 Apr 1998 13:09:41 +1000 (EST) Received: from goppelt.op.net (d-phlarc1-00.ppp.op.net [209.152.199.64]) by renoir.op.net (o1/$Revision: 1.16 $) with SMTP id XAA00270; Tue, 14 Apr 1998 23:09:28 -0400 (EDT) Message-Id: <199804150309.XAA00270(a)renoir.op.net> Comments: Authenticated sender is <edgee(a)cyberpass.net> From: "Ed G." <edgee(a)cyberpass.net> To: pete(a)dunnington.u-net.com (Pete Turnbull) Date: Tue, 14 Apr 1998 23:09:26 -0400 MIME-Version: 1.0 Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7BIT Subject: Re: Floating Point-How Important Reply-to: edgee(a)cyberpass.net CC: pups(a)minnie.cs.adfa.oz.au In-reply-to: <9804111346.ZM7828(a)indy.dunnington.york.ac.uk> References: "Ed G." <edgee(a)cyberpass.net> "Re: Floating Point-How Important to Unix?" (Apr 10, 22:40) X-mailer: Pegasus Mail for Win32 (v2.54) Sender: owner-pups(a)minnie.cs.adfa.oz.au Precedence: bulk Your query got me thinking about the various addressing modes of the PDP-11 and how they might affect my brute force approach to estimating floating point ops for C programs. Is this what you meant when you asked about position independent code? And yes, these addressing modes could mean the death knell for my approach. Index mode is definitely a problem as C programs seem to use r5 as a frame pointer with both positive and *negative* 16 bit offsets (see assembly language listing of my square root program below). I don't think PC relative mode (e.g., clr addr) is a problem (if the data segment follows the text, then the offsets would all be positive and all less than the size of the program). Is there such a thing as PC relative mode for the jmp op code? In other words, can you make long + or -32K relative jumps on the PDP-11? If so, this too could potentially confound my estimates. .globl _absv .text _absv: ~~absv: jsr r5,csv ~n=4 jbr L1 L2:clrf r0 cmpf 4(r5),r0 cfcc jge L4 movf 4(r5),r0 negf r0 jbr L3 jbr L5 L4:movf 4(r5),r0 jbr L3 L5:L3:jmp cret L1:jbr L2 .globl _mysqrt .text _mysqrt: ~~mysqrt: jsr r5,csv ~n=4 jbr L6 L7:~g=177762 ~err=177752 movf 4(r5),r0 divf $40400,r0 movf r0,-16(r5) .data L10000:77777;177776;177777;177777 .text movf 4(r5),r0 divf L10000,r0 movf r0,-26(r5) movf -16(r5),r0 movf r0,-(sp) mov $L9,-(sp) jsr pc,_printf add $12,sp L10:movf -16(r5),r0 mulf -16(r5),r0 subf 4(r5),r0 movf r0,-(sp) jsr pc,_absv add $10,sp cmpf -26(r5),r0 cfcc jgt L11 movf -16(r5),r0 mulf -16(r5),r0 addf 4(r5),r0 movf $40400,r1 mulf -16(r5),r1 divf r1,r0 movf r0,-16(r5) movf -16(r5),r0 movf r0,-(sp) mov $L12,-(sp) jsr pc,_printf add $12,sp jbr L10 L11:movf -16(r5),r0 jbr L8 L8:jmp cret L6:sub $20,sp jbr L7 .globl _main .text _main: ~~main: jsr r5,csv jbr L13 L14:.data L10001:77777;177776;177777;177777 .text movf L10001,r0 movf r0,-16(r5) ~n=177762 movf -16(r5),r0 movf r0,-(sp) jsr pc,_mysqrt add $10,sp movf r0,-(sp) mov $L16,-(sp) jsr pc,_printf add $12,sp L15:jmp cret L13:sub $10,sp jbr L14 .globl fltused .globl .data L9:.byte 111,156,151,164,151,141,154,40,147,165,145,163,163,72 .byte 40,45,56,61,66,146,12,12,0 L12:.byte 147,165,145,163,163,72,40,45,56,61,66,146,12,0 L16:.byte 12,115,171,40,163,161,165,141,162,145,40,162,157,157 .byte 164,40,151,163,72,40,45,56,61,66,146,12,0 Received: (from major@localhost) by minnie.cs.adfa.oz.au (8.8.5/8.8.5) id NAA02612 for pups-liszt; Wed, 15 Apr 1998 13:54:11 +1000 (EST) X-Authentication-Warning: minnie.cs.adfa.oz.au: major set sender to owner-pups(a)minnie.cs.adfa.oz.au using -f