----- Original Message ----- From: Ethan Dicks To: [email protected] Sent: Sunday, June 25, 2017 6:22 PM Subject: Re: [Simh] PDP-8 and OS/8 assembly
On Sun, Jun 25, 2017 at 5:50 PM, Bill Cunningham <[email protected]> wrote: > I am reading a bit about the machine the PDP-8. 4K fortran I guess was > used, That was one option, yes. > there were 8 "registers" if that's right. Not sure where this is coming from... Oh I'm sorry I meant operation codes. 3 registers. I believe 8 opcodes. There's the 12-bit Accumulator and its associated LINK (carry) bit. Some models always have a 12-bit MQ (Multiplier Quotient) register, some get an MQ when the EAE is installed, and some never get it. There's a 12-bit Program Counter, and two extended field registers, either 1-bit, 2-bit (PDP-8/L) or 3-bit (many other models) if the memory extension hardware is installed (required to have over 4K) > And 12 bit words. Yes. > As far as languages here, is Macro-8 assembly language? Look for assemblers called PAL (PAL III and PAL8) and MACREL (though MACREL was a late addition) OK > Is there an assembler available for PDP-8? OS/8 preferrably but tss-8 or > anything would do? Plenty of assembler possibilities with OS/8. I have no experience with TSS-8. http://www.computinghistory.org.uk/det/8391/PDP8-PALAssembly-Language/ -ethan OK I see. The registers other than AC and the two others are all I've heard of. Where Do I ge this... https://www.grc.com/pdp-8/pdp-8.htm Pretty nice page. I just found it earlier. Bill
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