Notes For V3.9

The makefile now works for Linux and most Unix's. However, 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 3.9-0

1.1.1 SCP and libraries

	- added *nix READLINE support (Mark Pizzolato)
	- added "SHOW SHOW" and "SHOW <dev> SHOW" commands (Mark Pizzolato)
	- added support for BREAK key on Windows (Mark Pizzolato)

1.1.2 PDP-8

	- floating point processor is now enabled

2. Bugs Fixed

Please see the revision history on http://simh.trailing-edge.com or
in the source module sim_rev.h.

3. Status Report

This is the last release of SimH for which I will be sole editor. After this
release, the source is moving to a public repository:

under the general editorship of Dave Hittner and Mark Pizzolato. The status
of the individual simulators is as follows:

3.1 PDP-1

Stable and working; runs available software.

3.2 PDP-4/7/9/15

Stable and working; runs available software.

3.3 PDP-8

Stable and working; runs available software.

3.4 PDP-10 [KS-10 only]

Stable and working; runs available software.

3.5 PDP-11

Stable and working; runs available system software. The emulation of individual
models has numerous errors of detail, which prevents many diagnostics from
running correctly.

3.6 VAX-11/780

Stable and working; runs available software.

3.7 MicroVAX 3900 (VAX)

Stable and working; runs available software. Thanks to the kind generosity of
Camiel Vanderhoeven, this simulator has been verified with AXE, the VAX
architectural exerciser.

3.8 Nova

Stable and working; runs available software.

3.9 Eclipse

Stable and working, but not really supported. There is no Eclipse-specific
software available under a hobbyist license.

3.10 Interdata 16b

Stable and working, but no software for it has been found, other than
diagnostics.

3.11 Interdata 32b

Stable and working; runs 32b UNIX and diagnostics.

3.12 IBM 1401

Stable and working; runs available software.

3.13 IBM 1620

Hand debug only.  No software for it has been found or tested.

3.14 IBM 7094

Stable and working as a stock system; runs IBSYS. The CTSS extensions
have not been debugged.

3.15 IBM S/3

Stable and working, but not really supported. Runs available software.

3.16 IBM 1130

Stable and working; runs available software.  Supported and edited by
Brian Knittel.

3.17 HP 2100/1000

Stable and working; runs available software. Supported and edited by
Dave Bryan.

3.18 Honeywell 316/516

Stable and working; runs available software.

3.19 GRI-909/99

Hand debug only.  No software for it has been found or tested.

3.20 SDS-940

Hand debug only, and a few diagnostics.

3.21 LGP-30

Unfinished; hand debug only. Does not run available software, probably
due to my misunderstanding of the LGP-30 operational procedures.

3.22 Altair (original 8080 version)

Stable and working, but not really supported. Runs available software.

3.23 AltairZ80 (Z80 version)

Stable and working; runs available software. Supported and edited by
Peter Schorn.

3.24 SWTP 6800

Stable and working; runs available software. Supported and edited by
Bill Beech

3.25 Sigma 32b

Incomplete; more work is needed on the peripherals for accuracy.

3.26 Alpha

Incomplete; essentially just an EV-5 (21164) chip emulator.

4. Suggestions for Future Work

4.1 General Structure

	- Multi-threading, to allow true concurrency between SCP and the simulator
	- Graphics device support, particularly for the PDP-1 and PDP-11

4.2 Current Simulators

	- PDP-1 graphics, to run Space War
	- PDP-11 GT40 graphics, to run Lunar Lander
	- PDP-15 MUMPS-15
	- Interdata native OS debug, both 16b and 32b
	- SDS 940 timesharing operating system debug
	- IBM 7094 CTSS feature debug and operating system debug
	- IBM 1620 debug and software
	- GRI-909 software
	- Sigma 32b completion and debug
	- LGP-30 debug

4.3 Possible Future Simulators

	- Data General MV8000 (if a hobbyist license can be obtained for AOS)
	- Alpha simulator
	- HP 3000 (16b) simulator with MPE

sim_timer.c

@@ -446,7 +446,8 @@ return (sim_idle_rate_ms != 0);
 
 t_bool sim_idle (uint32 tmr, t_bool sin_cyc)
 {
-uint32 cyc_ms, w_ms, w_idle, act_ms;
+static uint32 cyc_ms = 0;
+uint32 w_ms, w_idle, act_ms;
 int32 act_cyc;
 
 if ((sim_clock_queue == NULL) ||                        /* clock queue empty? */
@@ -456,7 +457,8 @@ if ((sim_clock_queue == NULL) ||                        /* clock queue empty? */
         sim_interval = sim_interval - 1;
     return FALSE;
     }
-cyc_ms = (rtc_currd[tmr] * rtc_hz[tmr]) / 1000;         /* cycles per msec */
+if (cyc_ms == 0)                                        /* not computed yet? */
+    cyc_ms = (rtc_currd[tmr] * rtc_hz[tmr]) / 1000;     /* cycles per msec */
 if ((sim_idle_rate_ms == 0) || (cyc_ms == 0)) {         /* not possible? */
     if (sin_cyc)
         sim_interval = sim_interval - 1;
@@ -469,11 +471,11 @@ if (w_idle == 0) {                                      /* none? */
         sim_interval = sim_interval - 1;
     return FALSE;
     }
-act_ms = sim_os_ms_sleep (w_idle);                      /* wait */
+act_ms = sim_os_ms_sleep (w_ms);                        /* wait */
 act_cyc = act_ms * cyc_ms;
 if (sim_interval > act_cyc)
-    sim_interval = sim_interval - act_cyc;
-else sim_interval = 1;
+    sim_interval = sim_interval - act_cyc;              /* count down sim_interval */
+else sim_interval = 0;                                  /* or fire immediately */
 return TRUE;
 }