upgrade ngspice to v31

1 files changed, 769 insertions, 0 deletions

diff --git a/Windows/spice/docs/NEWS b/Windows/spice/docs/NEWS
new file mode 100644
index 00000000..4bdb0012
--- /dev/null
+++ b/Windows/spice/docs/NEWS
@@ -0,0 +1,769 @@
+Ngspice-31, Sep 22nd, 2019
+============
+
+- New features:
+    + if a subcircuit is defined more than once, only read the first one and discard the others
+    + vbic model implementation including self-heating effect
+    + Enable the file input as additional search path for .include files also for non-Windows OSs
+    + add scope to decks and subcircuits (not yet fully implemented)
+    + enable 'res' as valid resistor model identifier
+    + Add variable 'nostepsizelimit' to relieve step size limit defined by TSTEP of the .tran command
+    + Windows GUI: make GUI more responsive
+    + if the comaptibility mode is PS, LTPS or LTPSA, '$' is treated as a valid character, not as
+      end-of-line comment delimiter
+    + allow very short version information with new options -v and -d to 'version' command
+    + the PSPICE area token for a device instance may be not only a number, but also a parametrized
+      token like {tok}
+    + Windows GUI: New history buffering
+    + Windows GUI: Added scrolling to input window
+    + update to hicum version 2.40
+    + allow " around netnames for .plot and .print commands
+    + command 'setcs': like command 'set' but case sensitive
+    + linearized cutout of an original vector by defining the vectors lin-tstart, lin-tstop,
+      and lin-tstep before sending the 'linearize' command
+    + new examples: inverters and ring oscillator using SOI
+    + 'option norefvalue' to suppress printing the reference value
+
+- Bug fixes:
+    + many bugs fixed and code improvements (patches 33 - 64, bug tracker nos. 390,
+      394, 395, 403, 404, 408)
+    + memory leaks removed
+
+Ngspice-30, Jan 1st, 2019
+============
+
+- New features:
+    + VDMOS device model has been overhauled extensively
+    + Making the manual is now much more flexible and comfortable,
+      xhtml manual added.
+    + Add pre-defined variable controlswait to enable running .control sections
+      after the simulation has finished (shared ngspice only)
+    + Add an icon to the MS Windows GUI build
+    + Enable more reliable memory usage data
+    + Support libtinfo
+    + add rotation angle to text output, vertcally aligned text for Postscript
+      and Windows y-axis plot labels
+    + enable postscript output for extended ascii. Currently only Western
+      European latin-1 (ISO/IEC 8859-1) encoding is supported
+    + Ancient Xgraph code removed
+
+- Bug fixes:
+    + many bugs fixed (bug tracker nos. 253, 332, 337, 368, 374, 375, 376, 377, 378,
+      379, 380, 381, 384, 385, 386)
+    + ancient bug removed that led to spurious heap corruption of shared ngspice
+      under (very sensitive) Windows 10
+    + memory leaks removed
+
+Ngspice-29, Sept 30th, 2018
+============
+
+- New features:
+    + new variable no_auto_gnd. If set, the automatic replacing of gnd by 0
+      is disabled
+    + new compatibility modes for 'set behavior=??'. ps sets PSPICE, lt sets
+      LTSPICE compatibility, ltps is both for a file added by .include command,
+      psa, lta, and ltpsa are the same for the whole netlist
+    + .if, .elseif, .endif is now evaluated recursively, nested .if are thus
+      enabled
+    + new code model sidiode, that is a simple diode, linear breakdown, reverse
+      and forward regions with smooth overlapp, and optional current limits
+    + configure flag --with-fftw3. If set to 'no', internal fast fourier is used
+      instead of fftw
+    + command setseed to set the seed value for the random number generator
+    + option seed=[val|random]
+    + variable inputdir to remeber and retrieve the last input file directory
+    + example directory 'digital' with analog, behavioral and digital example input files
+    + new XSPICE filesource, d_source, and state-machine examples
+    + + or - maybe part of instance name
+    + Quasi-saturation VDMOS example
+    + add environmental variable SOURCE_DATE_EPOCH to allow reproducible executables
+    + new parameters to command setplot: setplot next, setplot previous
+    + updates to commands cd, rusage, print
+    + introduce diode recombination current part (ISR, NR)
+    + update to bipolar and diode temperature equations
+
+- Bug fixes:
+    + several bug fixes
+    + lots of memory leaks removed, especially when XSPICE circuits are called several
+      times in a loop.
+
+
+Ngspice-28, May 27th, 2018
+============
+
+- New features:
+    + Licenses for ngspice distribution are DFSG compatible
+    + VDMOS power MOS model added
+    + if 'set ngbehavior=ps' is given in .spiceinit, device libraries loaded
+      via .include may have PSPICE syntax
+    + --enable-oldapps configure flag to compile the old, seldom used apps
+      ngnutmeg, ngmakeidx, ngmultidec, ngproc2mod, ngsconvert
+    + add command mc_source to internally re-load the circuit
+    + add command alterparam to alter the value of a parameter xxx given in .param xxx=value
+    + add the function i(xyz) to measure the current in node 1 of device xyz, to be
+      used in behavioral models.
+    + new label 'noretraceplot' for the 'plot' command, if graphs in a plot show unwanted
+      retracing lines.
+    + The hyphen '-' is a valid character in model, device and subcircuit names
+    + add noise for behavioral resistor
+    + add a new vector type "temperature"
+    + support instance parameter defaults on .model lines
+    + New functions for XSPICE event node data export from shared ngspice:
+      ngGet_Evt_NodeInfo(char*) and ngSpice_AllEvtNodes(void)
+    + 'edisplay' command now showing node name, node type and number of events per node
+    + add flag 'none' to the 'save' command for shared ngspice.
+      Output data will not be stored, but are available via callback function ng_data.
+    + add a function cm_get_circuit to allow accessing the circuit structure ckt
+      from within an XSPICE code model.
+    + add variable 'sim_status' to indicate if a simulation has been aborted
+    + add pkg-config file
+
+- Bug fixes:
+    + many, many ... as always
+
+
+Ngspice-27, Aug 28th, 2017
+============
+
+- New features:
+    + check for correct inductor coefficients
+    + add variable 'win_console'
+    + --enable-relpath configure flag to set preprocessor flag HAS_RELPATH
+    +    sets search path for spinit relativ to current directory
+    + The search path for .spiceinit is: current dir, HOME dir, USERPROFILE dir
+    + new function stddev to calculate the standard deviation of all elements of a vector
+    + xspice digital n-input x m-output look-up table gate
+    + xspice digital model d_lut (digital n-input look-up table gate)
+    + add variable $sharedmode (if shared ngspice is running), to be used in scripts
+    + enable msys2 for mingw compilation
+    + OMP support for bsim3v3.24 model
+    + bsim3v3.24: add model parameter lmlt (Channel length scaling)
+    + OMP support for BSIM4.5 model
+    + update and extension of command 'wrdata'
+    + option xmu to set damping in trapezoid integration
+    + command 'linearize' will take time data from transient analysis vector if no circuit is loaded
+    + two new commands: edisplay and eprvcd
+    +     'edisplay' will show a list of all event nodes
+    +     'eprvcd' will print all event nodes in vcd format
+    + XSPICE 2D and 3D table models
+    + add variable 'batchmode' which is set when command line option `-b' is active
+    + enable backquote substitution for Visual Studio console apps
+    + update how-to-ngspice-vstudio.txt
+    + update visualc directory and project files, add XSPICE code model generation by VS2015
+    + allow access to 4 GB memory of 32 bit ngspice on 64 bit Windows, 8 TB for 64 bit ngspice
+    + new variable `interactive'
+    + xspice, introduce cm_message_printf()
+    + add variable `width' to command "print line ..."
+    + support msys2
+    + favor exponential temperatur equation if all parameters tc1, tc2 and tce are given for R
+    + move libfftw3 sideways out of the ngspice tree
+    + remove visual studio 2008 .vcproj files
+    + visualc/sharedspice.vcxproj, updated and migrated with visual studio 2015
+    + `E..table {expr} {pairs}', `G..', allow an optional `=' after `table'
+    + `E..value=', `G..value=', allow `=' being optional
+    + introduce TCE, exponential temperature coefficient for R
+    + allow `temper' to be recognised when preceded by '='
+    + allow cross-compilation, especially for MinGW-w64
+    + allow "plot xlog ylog" (equiv to "plot loglog")
+    + extend qa test to hisimhv version 2
+    + update hisimhv model to version 2.2.0
+    + update hisim model to version 2.8.0
+    + .control variable "sqrnoise" to deliver noise data in squared representation
+    + noise analysis, deliver results in V/sqrt(Hz) and A/sqrt(Hz)
+    + add delvt0 for bsim4 models
+    + bug fixes for diode model
+    + allow a xspice circuit with exclusively xspice event nodes
+    + man pages for cmpp ngmakeidx and ngproc2mod
+    + implement `nint()'
+    + everywhere: ln to the base e, log to the base e, log10 to the base 10
+    + allow an optional '=' in ".func foo() = {expr}"
+    + bsim4, update to version 4.8
+    + update hisimhv to version 1.2.4
+    + cmc quality check for bsim3 model
+    + nested indexing for vectors
+    + option savecurrents to save current through all devices
+    + option interp to plot interpolated raw file data
+    + MS VS 2010 project file added for compatibility
+    + XSPICE: new callback function cm_get_path
+
+- Bug fixes:
+    + many, many ... as always
+
+Ngspice-26, Jan 4th, 2014
+============
+
+- New features:
+    + fft command may (optionally) use fftw3 library
+    + add nint() rounding function
+    + usage of 'temper' in behavioral devices
+    + check for soa (safe operating area) in several device models
+    + library processing rewritten completely to enhance ngspice
+      compatibility (.lib)
+    + include file processing rewritten to allow nesting and various
+      absolute and relative path names (.inc)
+    + asinh, acosh, atanh functions
+    + shared ngspice option added: ngspice optionally compiles as
+      a shared object or dynamic link library
+    + use a hash table to massively speed up parsing the netlist
+    + implement a very basic .if/.else block
+    + implement a signed power function `pwr' for controlled sources
+    + implement multiplier `m' in F, G source
+    + apply Area Calculation Method (ACM) to the bsim3v3.3 model
+    + implement `tc1', `tc2' instance parameters
+
+- Bug fixes:
+    + many, many ... please see
+      http://sourceforge.net/p/ngspice/ngspice/ci/master/tree/
+      and check the 'history' button on the upper right.
+    + removed memory leaks
+
+
+Ngspice-25, Jan 4th, 2013
+============
+
+- New features:
+    + add temperature coefficients for B source
+    + commands "mdump", "mrdump" to dump matrix to file
+    + allow `time', `temper', and `hertz' in expressions with behavioral R, L, C
+    + Enable ctrl-c to interrupt a simulation also for Windows GUI
+    + tests/bsim4: use the standard CMC model qa check
+    + implement exit code for command "quit"
+    + .nodeset all = value
+    + memristor code model in extradev
+    + new scalable diode model including tunnel component
+    + variable xtrtol may override the XSPICE reduction of trtol
+    + XSPICE example: delta-sigma converter
+    + XSPICE: new d_source model
+    + new option noopac
+    + bsim3: make additonal parameters accessible with @mxx[par]
+    + enable Mac OS X compilation
+    + option reseries = val
+    + commands "snsave", "snload"
+    + update hisim to version 2.7.0, new qa tests
+    + hisimhv update to version 1.2.3, new qa tests
+    + allow Ctrl-d to quit
+    + jfet model temperature extension, tcv and bex parameter
+    + speed up vector handling by hash table for vector address storage and retrieval
+    + update PSS code
+
+
+- Bug fixes:
+    + many, many ... please see
+      http://ngspice.git.sourceforge.net/git/gitweb.cgi?p=ngspice/ngspice;a=shortlog;pg=0
+    + remove memory leaks
+    + update tclspice for MS Windows
+    + adms3 removed due to licensing issues
+
+
+Ngspice-24, Jan 29th, 2012
+============
+
+- New features:
+    + .csparam allows to tranfer a param into a vector in .control ... .endc
+    + functions floor and ceil
+    + syntax Gxxx n1 n2 TABLE {expression} = (x0, y0) (x1, y1) (x2, y2)
+    + syntax Gxxx n1 n2 value={equation} or Exxx n1 n2 value={equation}
+    + variable strict_errorhandling to exit ngspice with exit code 1
+      if any error occurs during circuit parsing
+    + command altermod allows reading from file
+    + command "devhelp" to show available devices and describe device parameters
+    + command "inventory" to print the number of istances of each device.
+    + function cph(vec) delivers phase from a vector without jumps at +-PI
+    + enable 64 bit compilation in MS Visual Studio
+    + --adms3 flag to compile with (experimental) adms code
+    + still very experimental pss code
+    + command 'remcirc' to remove a circuit from the list
+    + command 'wrdata' aknowledges appendwrite and prints complex variables
+    + allow comment lines inside of command files
+    + path variable NGSPICE_INPUT
+    + 'Filesource' code model
+
+- Bug fixes:
+    + More on prototypes, type casts, reordering of functions, compiler warnings
+    + fix a numerical problem in the hisim2 and hisimhv models
+    + plot i(vdd) from a loaded rawfile
+    + fix the guard for device generated internal nodes (via CKTmkVolt())
+    + reduce memory leaks for command 'reset'
+    + parameter processing for nested .subckt
+    + bsim4/b4noi.c: correct init the correlated noise slot in noiseDens and lnNdens vector
+    + Many small bugs
+
+Ngspice-23, June 5th, 2011
+============
+
+- New features:
+    + Reduction of trtol to 1 only if 'A' devices in the circuit and xspice is enabled
+    + command wrs2p to write a s-parameter file using Touchstone vers. 1 format
+    + d_source d_state d_ram, test cases for those xspice codemodels
+    + transient noise simulation added to independent voltage and current sources
+    + Random telegraph noise added to independent voltage and current sources
+    + 'time = nnn' in stop command added
+    + random voltage generator option trrandom to independent voltage and current sources
+    + ngspice build possible in a separate directory (e.g. in ng-spice-rework/release)
+    + update FIND .. WHEN measurements
+    + diode & bjt temperature model update with tlev and tlevc
+    + merge bsim3v1a code with bsim3v0 and bsim3v1s code with bsim3v1
+    + bjt2: removed - all GP extensions of this model are now in the bjt model
+    + HiSIM_HV model vers. 1.2.1 added
+    + bsim3v32: delvto and mulu0 as instance parameters
+    + Replace HiSIM1 by HiSIM_2.5.1_Release_20110407
+
+- Bug fixes:
+    + More on prototypes, type casts, reordering of functions, compiler warnings
+    + allow models like 2N2904 or 2SK136 also in subcircuits
+    + fix sensitvity calculation (for the dc-2+.cir testcase)
+    + allow multiple call to setup w/ correct node collapsing
+    + Many small bugs
+
+Ngspice-22, Sept 26th, 2010
+============
+
+- New features:
+    + OpenMP multicore support for BSIM3, BSIM4, and BSIMSOI4
+    + reinstate {$var} expansion in interactive interpreter
+    + .TITLE line added
+    + update to 'spectrum' script
+    + par('expression') in .four, .plot, .print, .meas, .save commands
+    + command 'option' for use in spinit, .spiceinit, and in scripts
+    + adms procedure updated
+    + new random number generator, random functions sunif() and sgauss()
+    + ngspice manual updated
+
+- Bug fixes:
+    + Major code cleanup to reduce compiler/linker warnings: ansi function prototypes,
+      void/char pointers to named pointers, explicit type casts and many more
+    + Many small bugs
+
+
+Ng-spice-rework-21, Jun3, 13th 2010
+============
+
+- Updated Devices: BSIMSOI 4.3.1
+
+- New features:
+    + Compatibility: C, L, R, devices and E, G sources with expressions
+      Variables HERTZ, TIME, TEMPER added
+    + E, G sources with pwl function
+    + New manual
+    + Plotting with Gnuplot,
+    + Writing wrdata for simple text table to file
+    + .measure improved
+    + transmission line models improved
+
+- Bug fixes:
+    + Many small bugs, memory leaks, memory overflows
+
+Ng-spice-rework-20, November, 16th 2009
+============
+
+Ngspice release 20 is the second release of the simulator in 2009.
+
+- Fixes: model names starting with a number (1n4001) are now correctly parsed.
+  The .global command has been reinstated (it was previously disabled) and
+  error messages now display the corresponding line numberin the input deck.
+- New Features: .measure command for transient, ac and dc analyses (still not
+  complete, e.g. DERIV is missing).
+- Devices: Updated BISM4 model to revision 4.6.5. Added PWL (PieceWise Linear)
+  functionality for B (arbitrary generator) sources.
+
+
+Ng-spice-rework-19, April, 23rd 2009
+============
+
+Ngspice release 19 came early after release 18. It reveals an important work
+in compile scripts, many bug fixes in memory management, interface, and work in device models.
+
+- Compile scripts: tclspice and ADMS compiling fixes. Architecture compiling
+  fixes for SunOS, MS Visual Studio, MINGW, Cygwin.
+- Memory management: fixed memory leaks, modifies memory management for
+  MS Windows, integration of espice bugfixes and enhancements, bug fixes in
+  plots and cli interface.
+- Rework of BSim models, integration of EPFL-EKV model V2.63, ADMS models
+  mextram, hicum0, hicum2.
+
+
+Ng-spice-rework-18
+============
+
+Rework-18 is introduces several new features into ngspice. This is a major
+release that comes after more than three years. During the silent years
+ngspice developers worked in CVS to stabilize and introduce new features
+into the simulator.
+
+- Tclspice simulator library has been merged with ngspice. Now you can
+  compile ngapice or tclspice by asserting a configure switch. See README.tcl
+- New options have been introduced: brief, listing, autostop and scale
+- Support for .lib file has been introduced. This allows the use of
+  third party model libraries in ngspice.
+- .measure statements: avg, integ, rms, max, min, delay, param
+- .global statements t support for global nodes whose name is not expanded
+  when flattening the netlist.
+- .func macros for inlining functions into netlists.
+- Improved the numparam library to support fully parametrized netlists.
+- BSIM model binning.
+- new multi-input gate VCVS using XSPICE extensions.
+
+
+Ng-spice-rework-17
+============
+
+This is a bug fix release. Previous release tarball did not included
+an include file necessary for compiling numparam library.
+
+
+Ng-spice-rework-16
+============
+
+Rework-16 comes out after almost one year of CVS development (from
+15-fixedRC3). This release improves ngspice in three ways:
+
+- Bug fixing: most of the bugs that affected rework-15 have been fixed,
+    thus ngspice is more stable, especially the xspice extension, the
+    subcircuit (X devices) handling and the numparam library.
+
+- New features: netlist syntax has been expandend allowing for end-of-line
+    comments. A ".global" card has beed added to define global nodes, i.e.
+    nodes that are not expanded in subcircuits. It is possible to define TC
+    for resistors on the instance line. The editline library can be used
+    instead of readline (no more GPL license violation).
+
+- Porting: ngspice now works (with xspice extension) on Windows using
+           MINGW/MSYS.
+
+
+Ng-spice-rework-15
+============
+
+Rework-15 release is a giant leap forward for ngspice. It incorporates
+many (read most) of the improvements implemented in tclspice during the
+two years long "sleep" of ngspice and adds many others. The incomplete
+list of new features incorporated are:
+
+  - Xspice simulator (with codemodel dynamic loading support):
+     a mixed signal simulator built upon spice3.
+
+  - Cider simulator:
+     a mixed level simulator built upon spice3.
+
+  - Numparam library:
+     a library that allows for parameter substitution at netlist level.
+
+  - Improved models:
+     Diode model includes periphery effects and high level of injection effects,
+     BJT and BJT2 enhanced.
+     BSIM3 now includes ACM.
+     BSIM4 implementation corrected.
+
+   -New models:
+     VBIC (3 Terminals, no excess phase and thermal network),
+     HiSIM.
+
+   - Frontend leaks closed.
+      Now frontend works as it should.
+
+   - Many new example file.
+
+   - Xgraph plotting program included.
+
+
+Ng-spice-rework-14
+============
+
+This is a major release in terms of bug-fixes. Some enhancements
+have been included: BSIM4 model and support for EKV model. The
+source code for the latter must be obtained from EKV web site
+(see DEVICE for more info). To enable EKV support you have
+to obtain the code first and then use the configure switch
+"--enable-ekv".
+
+The spice code contains an option to debug frontend code, now
+this is available in configure as "--enable-ftedebug".
+
+
+
+Ng-spice-rework-13
+============
+
+This is a major release in terms of fixes and enhancements.
+A garbage collector support has been added. If the configuration
+script detects that you have installed GC (Bohem-Weiser conservative
+garbage collector), it will use it. Some memory leaks have been
+fixed too.
+
+Enhancements to the code comes from Alan's contribute code, a
+description of improvements follows (extracted form Alan's mail):
+
+Output File Format Changes -
+
+  (NOTE: Do not rely on this, we may revert to the old format
+   in the next release).
+
+  Text mode .OP results even though "rawfile" written.
+
+  Internal device nodes are not saved to "rawfile" (reduces
+  file size). Optionally, these internal nodes can be replaced
+  by device currents and saved.
+
+
+DC Convergence Enhancements -
+
+  "Source-Stepping" algorithm modified with a "Dynamic" step size.
+  After each successful step, the node voltages are saved, the
+  source-factor is increased by the step-factor, and the step-factor
+  is increased (for the next step). If the step fails, i.e. the
+  circuit does not converge, the source-factor is set to the value
+  from the previous successful step, the previously stored node
+  voltages are restored, the step-factor is reduced, the source
+  factor is increased by this smaller step-factor, and convergence
+  is attempted again.
+
+  Same thing done for "Gmin-stepping" algorithm.
+
+  "Gshunt" option added. This sets the "diagGmin" variable used in
+  the gmin-stepping algorithm to a non-zero value for the final
+  solution. (Normally this is set to zero for the final solution).
+  This helps for circuits with floating nodes (and for some others
+  too).
+
+  The Gmin implementation across the substrate diodes of MOS1, MOS2,
+  MOS3, MOS6 and BSIM3 devices, and across BJT base-emitter and
+  base-collector diodes, was incorrect. Correcting this dramatically
+  improved DC convergence. (I think this also affects BSIM1 and 2
+  but I haven't fixed them yet !)
+
+  The gm, gmb and gds calculations in the MOS3 model were all wrong.
+  The device equations were fixed, leading to much improved
+  convergence.
+
+  The Vcrit value used for diode voltage limiting was calculated
+  without taking into account the device area (and in some cases
+  without using the temperature corrected saturation current).
+  This could cause floating point overflows, especially in device
+  models designed to be scaled by a small area, e.g. 2u by 2u diodes
+  (area=4e-12). This is now fixed for Diode, BJT, MOS1, MOS2, and
+  MOS3 models.
+
+  The diode voltage limiting was modified to add negative voltage
+  limiting. Negative diode voltages are now limited to 3*Vdp-10,
+  where Vdp is the voltage from the previous iteration. If Vdp is
+  positive, then the voltage is limited to -10V. This prevents some
+  more floating point overflows. (Actually, I'm still playing with
+  the best values for this).
+
+  The Spice3 "fix" for the MOS3 gds discontinuity between the
+  linear and saturated regions only works if the VMAX parameter
+  is non-zero. A "tweak" has been added for the VMAX=0 case.
+
+
+Transient Convergence Enhancements -
+
+  Temperature correction of various diode capacitances was implemented
+  slightly incorrectly, leading to capacitance discontinuities in
+  simulations at temperatures other than nominal. This affected the
+  Diode and MOS3 models.
+
+  A mistake in the implementation of the MOS3 source-bulk capacitance
+  model resulted in a charge storage discontinuity. This has been fixed.
+
+  The level 2 MOSFET model seems to calculate Von and Vth values for
+  the threshold and subthreshold values respectively, but then uses
+  Vbin to calculate the Vdsat voltage used to find the drain current.
+  However, a jump statement uses Von to decide that the device is in
+  the "cutoff" region, which means that when this jump allows the
+  drain current to be calculated, Vdsat can already be well above
+  zero. This leads to a discontinuity of drain current with respect
+  to gate voltage. The code is now modified to use Vbin for the jump
+  decision. It looks like the code should actually use Vth as the
+  threshold voltage, but since other SPICE simulators follow the
+  original Berkeley code, this was left alone.
+
+
+New Model Parameters -
+
+  A device multiplier instance parameter "M" (i.e. M devices in
+  parallel) was added to the MOS1,2,3 and BSIM3 mosfet models.
+
+
+Input Read-in and Checking -
+
+  Numbers beginning with a + sign got the input routine confused.
+  Fixed now.
+
+  Attempts to nodeset (or .IC) non-existent nodes are flagged with a
+  warning.
+
+  PWL statements on Voltage or Current sources are now checked for
+  "non-increasing" time-points at the start of the simulation.
+  Previously each time-point was checked as it was reached during
+  the simulation, which could be very annoying if you made a mistake
+  which caused the simulation to fail after hours of run-time.
+
+  A check which was performed at the end of each sub-circuit expansion
+  was moved to the top level. This check makes sure that all sub-circuits
+  have been defined, but in its original position, it meant that if a
+  sub-circuit included ANY .MODEL statements at all, then ALL the models
+  called in that sub-circuit must also be defined within that
+  sub-circuit. Now SPICE behaves as expected, i.e. a subcircuit may
+  define its own models, but may also use models defined at any level
+  above.
+
+
+Miscellaneous Fixes/Enhancements -
+
+  MOS devices reported only half of the Meyer capacitances, and did not
+  include overlap capacitances, when reporting to the .OP printout, or
+  when storing device capacitances to the "rawfile".
+
+  The ideal switch devices had no time-step control to stop their
+  controlling voltages/currents overshooting the switching thresholds.
+  The time-step control has been modified to use the last two time
+  points to estimate if the next one will move the controlling
+  voltage/current past a switching threshold. If this looks likely,
+  then the time-step is reduced.
+
+  The "rawfile" writing routines have been modified to print the
+  "reference value" to the console during the simulation. This lets
+  the user see exactly how far and how fast the simulation is
+  proceeding.
+
+  .OP printout tidied up a lot to make the printout clearer.
+
+  Analysis order changed to fix a "feature" where, if you ask for
+  a .OP and a .TRAN in the same simulation, the node voltages
+  printed out correspond to the .OP, but the device data was from
+  the last timepoint of the .TRAN
+
+
+Etc. -
+
+  There are other minor bug fixes, and changes to reduce compiler
+  warnings. There are probably some more significant fixes which
+  I've forgotten :-)
+
+
+Ng-spice-rework-12
+============
+Arno did a great work this summer!
+The pole-zero analysis has been corrected. The error was introduced
+in an attempt to eliminate compiler warnings. The source has been
+reworked and info file have been updated. As you may see, a new dir
+called "spicelib" has been created, another step toward the separation
+of the simulator from the frontend.
+
+Ng-spice-rework-11
+============
+
+Resistor code (device) has been modified to conform to spice3 device
+coding standard.
+A new step function (U2) has been introduced.
+Documentation updated.
+
+Ng-spice-rework-10
+============
+
+Added BSIM4 model and closed a couple of serious bugs. Added DEVICES
+file to distribution. This file contains the status of device models
+in this simulator. Read it, this file can save you a lot of time.
+
+Ng-spice-rework-9
+============
+
+Thanks to Arno Peters now all device models are dynamically loaded on
+demand.  They are linked as shared libraries. The next step is the
+dlopen() one which will make possible to link devices without any
+recompilation.
+
+
+
+Ng-spice-rework-8
+============
+
+Applied Arno's patch.
+
+From his mail message:
+
+Hi Paolo,
+
+I have prepared a source cleaning patch.
+
+Features:
+
+  + patches don't get polluted with differences between automatically
+  generated Makefile.am files.  Usually these make up the biggest part
+  of the patches.  This allows me to read the patch on the mailing
+  list instead of sifting through 90% redundant and irrelevant changes.
+
+  + the shell script autogen.sh automatically regenerates the required
+  files if the user has automake, autoconf and libtool installed.
+
+  + this feature is only valuable to developers, not to end users.
+
+
+Usage of this patch, once incorporated:
+
+  # create a working tree to work from
+  cp -a ng-spice-rework-x ng-spice
+
+  [ Changes made to ng-spice ]
+
+  # clean up all the automatically generated files
+  cd ng-spice; make maintainer-clean
+
+  # extract the differences
+  diff -ruN ng-spice-rework-x ng-spice > my.patch
+
+  [ Patch sent to ng-spice mailing list or you ]
+
+  # incorporate changes into the tree
+  cd ng-spice-rework-x; patch -p1 < my.patch
+
+  # update the automatically generated files
+  cd ng-spice-rework-x; sh autogen.sh
+
+
+
+
+Ng-spice-rework-7 (22 Mar 2000)
+============
+
+Bug fix release
+
+
+
+Ng-spice-rework-6 (29 Jan 2000)
+============
+
+This porting includes:
+
+1) BSIM3V3.1 model as level 49. This is the version modified by Serban
+Popescu which understands the M parameter and implements HDIF.
+
+2) BSIM3V3.2 model al Level 50. This is the standard Berkeley version.
+
+3) Now the resistor model can accepts two different values for DC and
+AC resistance.
+
+
+
+Ng-spice-rework-5 and 5_2  (Jan 2000)
+============
+
+Internal development release, buggy and not working.
+
+Ng-spice-rework-4  (22/12/99)
+============
+
+This porting includes a new feature:
+
+1) dynamically loading of some device code as an experimental feature
+for the future GPL simulator. Thanks to Arno Peters and Manu Rouat.
+
+2) Patched the following bug (thanks to Andrew Tuckey for having
+supplied the patch).
+
+    * Wsw (current controlled switch) in subckt, parsing bug.
+    * scale factor in arbitrary source.
+    * bug in noise analysis.
+    * save segmentation faults.
+
+