17 Mar
2018
17 Mar
'18
10:10 p.m.
On Mar 17, 2018, at 6:57 PM, Fritz Mueller <fritzm
at fritzm.org> wrote:
I have a question about floating CSR allocation on PDP-11s. Both the 1976 and 1981
versions of the PDP-11 peripherals handbook indicate the floating CSRs are to be allocated
starting at address 760010. However, both the XXDP FLOAT program and simh's
autoconfig suggest I should set my DZ11 (first floating CSR device in my config) to
760100. Anyone know what gives?
Ah, I found the answer in the DZ11 technical manual: gaps are left for between each device
type that gets a floating CSR. So for one DZ11, you get:
gap 160010 (no DJ11s)
gap 160020 (no DH11s)
gap 160030 (no DQ11s)
gap 160040 (no DU11s)
gap 160050 (no DUP11s)
gap 160060 (no LK11s)
gap 160070 (no DMC11s)
DZ11 160100