Here's a PDP11 SIMH bug as old as the simulator itself: the reset_cpu routine sets the PS to 340 (interrupts disabled). This causes some versions of Lunar Lander not to work. In fact, the initial state of the PS is not architecturally standardized:
04: cleared (from schematics)
05: cleared (from manual)
20: cleared (from schematics)
34: cleared (from schematics), set to 340 on boot?
40: cleared (from schematics)
44: cleared on init, set to 340 on boot (from schematics, manual)
45: cleared (from schematics)
60: cleared (from schematics)
70: cleared (from schematics)
T11: set to 340 (from spec)
LSI11, F11: 4 mode behavior (from memory on power recovery, cleared on GO, 340 on boot, mode 3 undefined)
J11: 4 mode behavior (from memory on power recovery, cleared on GO, 340 on boot, 340 on jump to custom PROM)
The story seems to be this. All non-VLSI PDP11s used TTL chips to implement the PS, either discrete flip-flops, or 4b registers, or both.
Starting with the first system, the 11/20, they were wired clear on the processor INIT signal (power-up or front panel START switch), so that all internal state started as 0. This worked fine, because START also reset the Unibus and cleared all interrupt enables. So even though the processor was as IPL = 0, no interrupts were possible. Then along came the LSI11...
The LSI11 implemented a line-time clock with NO INTERRUPT DISABLE. Thus, if IPL was left at 0 and a bootstrap routine from a slow device was started (e.g., a floppy drive), the clock would tick, and an interrupt would occur, before the bootstrap routine finished. Because no vectors were set up, the processor would crash. So the LSI11 started the practice, carried over to all later PDP11 VLSI chips, of setting the PS to 340 before jumping to a boot ROM.
The T11 did this in all modes of startup, because its only startup behavior was to jump to a "boot" routine. It did not have a console of any kind.
Accordingly, it appears that the cpu_reset routine needs to set the PS based on the processor model. Further, all boot routines need to set the PS to 0 or 340 based on the processor model. (It's probably safe for boot routines just to set the PS to 340, but it's not technically
accurate.)
The makefile now works for Linux and most Unix's. Howevr, for Solaris
and MacOS, you must first export the OSTYPE environment variable:
> export OSTYPE
> make
Otherwise, you will get build errors.
1. New Features
1.1 3.8-0
1.1.1 SCP and Libraries
- BREAK, NOBREAK, and SHOW BREAK with no argument will set, clear, and
show (respectively) a breakpoint at the current PC.
1.1.2 GRI
- Added support for the GRI-99 processor.
1.1.3 HP2100
- Added support for the BACI terminal interface.
- Added support for RTE OS/VMA/EMA, SIGNAL, VIS firmware extensions.
1.1.4 Nova
- Added support for 64KW memory (implemented in third-party CPU's).
1.1.5 PDP-11
- Added support for DC11, RC11, KE11A, KG11A.
- Added modem control support for DL11.
- Added ASCII character support for all 8b devices.
1.2 3.8-1
1.2.1 SCP and libraries
- Added capability to set line connection order for terminal multiplexers.
1.2.2 HP2100
- Added support for 12620A/12936A privileged interrupt fence.
- Added support for 12792C eight-channel asynchronous multiplexer.
2. Bugs Fixed
Please see the revision history on http://simh.trailing-edge.com or
in the source module sim_rev.h.
1. New Features
1.1 3.7-0
1.1.1 SCP
- Added SET THROTTLE and SET NOTHROTTLE commands to regulate simulator
execution rate and host resource utilization.
- Added idle support (based on work by Mark Pizzolato).
- Added -e to control error processing in nested DO commands (from
Dave Bryan).
1.1.2 HP2100
- Added Double Integer instructions, 1000-F CPU, and Floating Point
Processor (from Dave Bryan).
- Added 2114 and 2115 CPUs, 12607B and 12578A DMA controllers, and
21xx binary loader protection (from Dave Bryan).
1.1.3 Interdata
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state.
1.1.4 PDP-11
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (WAIT instruction executed).
- Added TA11/TU60 cassette support.
1.1.5 PDP-8
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (keyboard poll loop or jump-to-self).
- Added TA8E/TU60 cassette support.
1.1.6 PDP-1
- Added support for 16-channel sequence break system.
- Added support for PDP-1D extended features and timesharing clock.
- Added support for Type 630 data communications subsystem.
1.1.6 PDP-4/7/9/15
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (keyboard poll loop or jump-to-self).
1.1.7 VAX, VAX780
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (more than 200 cycles at IPL's 0, 1, or 3 in kernel mode).
1.1.8 PDP-10
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (operating system dependent).
- Added CD20 (CD11) support.
2. Bugs Fixed
Please see the revision history on http://simh.trailing-edge.com or
in the source module sim_rev.h.
1. New Features
1.1 3.7-0
1.1.1 SCP
- Added SET THROTTLE and SET NOTHROTTLE commands to regulate simulator
execution rate and host resource utilization.
- Added idle support (based on work by Mark Pizzolato).
- Added -e to control error processing in nested DO commands (from
Dave Bryan).
1.1.2 HP2100
- Added Double Integer instructions, 1000-F CPU, and Floating Point
Processor (from Dave Bryan).
- Added 2114 and 2115 CPUs, 12607B and 12578A DMA controllers, and
21xx binary loader protection (from Dave Bryan).
1.1.3 Interdata
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state.
1.1.4 PDP-11
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (WAIT instruction executed).
- Added TA11/TU60 cassette support.
1.1.5 PDP-8
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (keyboard poll loop or jump-to-self).
- Added TA8E/TU60 cassette support.
1.1.6 PDP-1
- Added support for 16-channel sequence break system.
- Added support for PDP-1D extended features and timesharing clock.
- Added support for Type 630 data communications subsystem.
1.1.6 PDP-4/7/9/15
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (keyboard poll loop or jump-to-self).
1.1.7 VAX, VAX780
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (more than 200 cycles at IPL's 0, 1, or 3 in kernel mode).
1.1.8 PDP-10
- Added SET IDLE and SET NOIDLE commands to idle the simulator in wait
state (operating system dependent).
- Added CD20 (CD11) support.
2. Bugs Fixed
Please see the revision history on http://simh.trailing-edge.com or
in the source module sim_rev.h.
