Re: [Simh] More on DMA to IO page

2018-09-06 Thread Mark Pizzolato
On Thursday, September 6, 2018 at 1:00 PM, Bob Supnik wrote: > Looking at the DEC ChipKit documentation, [...] > So my conclusion is that IO mapped PDP11s (which are, of course, always > Unibus) do support DMA to IO space, so you could put a GT40 (in theory) on a > Unibus J11, and it would

Re: [Simh] More on DMA to IO page

2018-09-06 Thread Johnny Billquist
On 2018-09-07 00:38, Eric Smith wrote: On Thu, Sep 6, 2018 at 4:31 PM, Johnny Billquist > wrote: Well, you'd probably also need to deal with the Unibus map handling, since those addresses also do not generate accesses directly on the memory bus... Really?

Re: [Simh] More on DMA to IO page

2018-09-06 Thread Eric Smith
On Thu, Sep 6, 2018 at 4:31 PM, Johnny Billquist wrote: > Well, you'd probably also need to deal with the Unibus map handling, since > those addresses also do not generate accesses directly on the memory bus... Really? What's the highest physical address the Unibus map supports?

Re: [Simh] More on DMA to IO page

2018-09-06 Thread Johnny Billquist
On 2018-09-07 00:26, Eric Smith wrote: On Thu, Sep 6, 2018 at 4:12 PM, Johnny Billquist > wrote: The problem is that the MK11 memory boxes also have CSRs, and those are living in that last 8K space. If you have memory mapping those same addresses, I have no

Re: [Simh] More on DMA to IO page

2018-09-06 Thread Eric Smith
On Thu, Sep 6, 2018 at 4:12 PM, Johnny Billquist wrote: > The problem is that the MK11 memory boxes also have CSRs, and those are > living in that last 8K space. If you have memory mapping those same > addresses, I have no idea what happens, but either way is not good. Either you have the

Re: [Simh] More on DMA to IO page

2018-09-06 Thread Johnny Billquist
On 2018-09-06 22:36, Eric Smith wrote: On Thu, Sep 6, 2018 at 1:59 PM, Bob Supnik > wrote: Now, as to bus maps. The 11/70 bus map has a jumper-adjustable upper limit for what parts of Unibus address space go through the map, and what parts are resolved on the

Re: [Simh] More on DMA to IO page

2018-09-06 Thread Timothe Litt
On 06-Sep-18 16:17, Paul Koning wrote: > >> On Sep 6, 2018, at 3:59 PM, Bob Supnik wrote: >> >> ... >> Personally, I like Tim's solution of a private interface between consenting >> devices. That would certainly work for the GT40 and its ROM too. > But if it's a private interface, that means

Re: [Simh] More on DMA to IO page

2018-09-06 Thread Eric Smith
On Thu, Sep 6, 2018 at 1:59 PM, Bob Supnik wrote: > Now, as to bus maps. The 11/70 bus map has a jumper-adjustable upper limit > for what parts of Unibus address space go through the map, and what parts > are resolved on the Unibus itself. The maximum value is 76; that is, > the IO page can

Re: [Simh] More on DMA to IO page

2018-09-06 Thread Paul Koning
> On Sep 6, 2018, at 3:59 PM, Bob Supnik wrote: > > ... > Personally, I like Tim's solution of a private interface between consenting > devices. That would certainly work for the GT40 and its ROM too. But if it's a private interface, that means you couldn't do a KMC emulation which runs KMC

[Simh] More on DMA to IO page

2018-09-06 Thread Bob Supnik
Looking at the DEC ChipKit documentation, it seems fairly clear that a device implemented with the DC003/5/6/10/21 series of chips never drives BBS7. BBS7 is an input to the address matching logic implemented in the DC005, but that's it. On the other hand, the DEC Standard for the LSI11 bus