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       Release Notes for V-System/Windows V4.2e (29 Jun 1994)

This release incorporates the Direct Compile technology developed by Model 
Technology Incorporated. Direct Compile yields significant performance 
improvements over the previous (interpreted) version. Users should see a 3-5x 
compile speed improvement and 5x to 50x improvement in simulation runtime. 
Simulation load times however, have slowed slightly.

Since this release uses an entirely new library format, it is necessary to 
recompile all design units before simulating them. In order to conserve disk 
space, it would be best to delete the old libraries before recompiling them.

V-System/Windows is now a 32-bit Windows application using the WIN32S 
interface supplied by Microsoft. Win32S allows a 32-bit application to run 
under Windows 3.1 and DOS, which are both 16-bit. The Win32S libraries and 
support files must be installed first before the V-System/Windows product. 
The Win32S files are provided on two disks labeled "Win32S Version 1.15". 
Please see the installation instructions for more information.

The user interface has been changed to make the product easier to use. 
Current users of V-System/Windows should have no problems using the new 
version. Here is a brief summary of the changes:

*  The main V-System menu bar at the top of the main application window used 
to change depending on which subwindow was active. Now it is always the same 
no matter which subwindow is active. Instead, the Wave and List Windows each 
have their own menu bars. In addition, the menus for these windows can be 
"popped up" by clicking the right button anywhere in the list window, or in 
the area with the signal names in the wave window.

*  The main window and all the subwindows now remember when they've been 
maximized or minimized between program invocations.

*  Some improvements have been made to the VSIM PostScript output.

*  The "Windows > Tile" menu entry has changed to "Tile Horizontally" and 
"Tile Vertically".

With this release the Model Technology Direct Compile V-System/Windows now 
supports the following features:

*  Support for Microsoft Windows/NT
*  Full IEEE 1076-1993 VHDL Standard support (see below)
*  64-bit TIME and REAL types
*  Force command improved to provide over-riding force (see below)
*  TSSI vector file format read and write (see below)
*  VITAL support (see below)
*  Signal optimizations (see below)
*  VSIM command to temporarily disable breakpoints (see below)

NOTE FOR WINDOWS/NT USERS:

Included with the product are command-line versions of vcom, vdel, vdir, 
vmap, and vlib. These are located in the "nt_cmds" subdirectory of the 
installation directory. To use the vcom command, you will need to have the 
files vcom.exe and vcom.dll in the same directory, or modify your search path 
to find both of these files where they are installed. The easiest way to do 
this is to move all the files from the "nt_cmds" subdirectory up one level to 
where vsystem.exe and vcom.dll are. Then everything should work fine.

To run the simulator from the command line, you can use the "-do" command to 
invoke the main application and tell it to simulate a circuit. For example, 
type:
    vsystem -do "vsim -t fs testbench; run 100; exit -f"
or
    vsystem -do "run_test.do"         (put the commands in the "do" file)

FORCE COMMAND IMPROVED TO PROVIDE OVER-RIDING FORCE

    FORCE [-FREEZE|-DRIVE|-DEPOSIT] [-REPEAT <period>] <signal_name>
           <value> [<time>] {,<value> <time>}

The -repeat switch has been moved to the front to be consistent with other 
VSIM commands. It's still allowed at the end for backward compatibility.

-FREEZE : The signal is frozen at the specified value until it is forced
again or until it is unforced with NOFORCE.

-DRIVE : A driver is attached to the signal and drives the specified value 
until the signal is forced again or until it is unforced with NOFORCE. This 
option is illegal for unresolved signals.

-DEPOSIT : The signal is set to the specified value. The value remains until 
there is a subsequent driver transaction, or until the signal is forced 
again, or until it is unforced with NOFORCE.

If none of these options are specified then "-FREEZE" is assumed for 
unresolved signals and "-DRIVE" is assumed for resolved signals. This should 
allow your existing force files to work without any change.

Because you might prefer that "-FREEZE" be assumed for unresolved and 
resolved signals, the "vsystem.ini" file accepts a "DefaultForceKind" entry 
under the "vsim" section. This specifies the default force kind. For example,
        [vsim]         ; The choices are freeze, drive, and deposit
        DefaultForceKind = freeze

The NOFORCE command now removes the effect of any forces on the specified 
signal (not just repeating forces). It also causes the signal's effective 
value to be re-evaluated and the signal to become active.

The GUI force dialog box has been updated to allow selection of "freeze", 
"drive", or "deposit". Also, a zero delay force will cause the change to 
occur in the current delta rather than in the next delta. This should be less 
confusing for the user, especially with repeating forces in which the first 
waveform element has zero delay (all subsequent transitions for the first 
element used to occur at delta 1 rather than delta 0).

TSSI VECTOR FILE SUPPORT:

The WRITE TSSI command records the contents of the List window in a TSSI 
format file. The file contains simulation data for all signals displayed in 
the List window which can be converted to TSSI format. A signal definition 
file is also generated.
     WRITE TSSI <filename>

The TSSI2MTI command is used to convert a vector file in TSSI Standard Events 
Format into a sequence of simulator FORCE and RUN commands. The stimulus is 
written to standard output.
    TSSI2MTI <signal_definition_file> [<SEF_vector_file>]

VITAL support

V-System is compliant with the VITAL Model Development Specification (version 
v2.2b). To simulate VITAL models you must obtain the VITAL VHDL timing and 
primitives packages and compile them under V-System. The current release of V-
System correctly simulates the VITAL packages, but the packages are not 
accelerated. Acceleration will be available in an upcoming release.

V-System also supports back-annotation of VITAL models from Standard Delay 
Format files (SDF). The rules for mapping SDF constructs to VHDL generic 
names are described in the VITAL Model Development Specification (version 
v2.2b). The current release of V-System reads version 2.0 SDF, not 2.1 SDF as 
described in the VITAL specification. V-System will read version 2.1 SDF in 
the same release that VITAL acceleration is provided. The specification for 
SDF is available from Open Verilog International (OVI).

VSIM can directly read a single SDF file during the elaboration of the 
design. VSIM assumes that the SDF instance names are relative to the root of 
the design being simulated. A future release of V-System will support 
multiple SDF files associated to user-selected instances in the design. The 
following VSIM option switches control the SDF import:

-sdfmin <SDF-filename>
	select minimum timing from the SDF

-sdftyp <SDF-filename>
	select typical timing from the SDF

-sdfmax <SDF-filename>
	select maximum timing from the SDF

-sdfnowarn
	disable warnings from the SDF reader

VSIM COMMAND TO TEMPORARILY DISABLE BREAKPOINTS

The VSIM DISABLEBP command will temporarily turn off all breakpoints. The 
ENABLEBP command will turn them on again. You might find this useful if you 
want to run forward to a certain time point before allowing breaks to occur.

CHANGES TO MANUAL

There is an error in step 14 on page 3-34; it should read:
Select testbench(adder8) in the Structure window by clicking on the name
before going on.

The menu command that was used to change variable values has been removed. 
Two pages in the V-System/Windows Users Guide must be changed.

page 3-37, Step 26 should read:
Now change the value of the sum record with the change command. Type:
    change test_patterns(6).sum 00000111

page 6-29, second paragraph should read:
Variables are shown in a hierarchical display which can be collapsed and 
expanded. A variable value can be changed with the VSIM change command.
