PDP-11 floating CSRs: 760010, or 760100?

[Fritz Mueller]

> 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