New in 0.29
* Initial implementation of embedded PSL assertions.
* Improve speed of non-sensitized processes.
* Improve speed of string case statement (dichotomy instead of linear search).
* bug fix and improvments in SDF annotator.
* bug fix when the bound of a string literal type is not locally static.
* bug fix: gcov crash

New in 0.28 (2009-09-17)
* Add --std=08 to enable vhdl 2008 features.
* Support all-sensitized processes from vhdl 2008.
* bug fix: handle 'pos/'leftof/'rightof/'succ/'pred in concurrent statements.
* bug fix: overloaded resolution functions.
* bug fix: direct drivers elaboration for unconstrained array signals.
* Documentation typos (thanks to Peter Huewe).
* many minor bugs fixed.

New in 0.27 (2008-07-01)
* Improve SDF annotation (handles much more annotations)
* Add --ieee-asserts= option to control assert messages from ieee packages.
* bug fix: aliases in port map
* bug fix: crash during elaboration for top entities with ports/generic
* bug fix: crash when string literal in aggregate.
* bug fix: concatenation with an array subtype element.
* bug fix: non-static subtype used by type conversions in associations.
* bug fix: clear timeout in wait for.
* minor bugs fixed.

New in 0.26 (2007-04-08)
* GHDL_PREFIX environment variable overrides default installation prefix.
* simulation speed improved with 'direct drivers'.
* windows version: exceptions are caught
* windows version: use executable path instead of registry for prefix
* bug fix: individual association by expression (was not working)
* bug fix: individual association of string
* bug fix: within windows code generator
* bug fix (windows): large local variables crashed
* bug fix: crash when overloaded aggregate target.
* bug fix: forbid individual association with open
* bug fix: crash when bad array prefix
* bug fix: correctly extract sensitivity of record aggregate

New in 0.25 (2006-08-11)
* bug fix: ieee math libraries available when --ieee=synopsys.
* bug fix: 'image in package bodies.
* bug fix: scan of fp literals.
* bug fix: interface identifier is checked for conformance rules.
* bug fix: avoid a crash in case of error in configuration specification.
* bug fix: non-static choice in unidim case are now correctly checked.
* bug fix: do not crash in case of bad use of incomplete type.
* bug fix: 'range are not expressions.
* bug fix: handle file declaration in concurrent procedure calls.
* bug fix: correctly handle static 'image attribute.
* bug fix: handle in-conversion for signal associated with an expression.
* bug fix: emit an error when a function tries to exit without a return.
* vpi functions to schedules values.
* math_real now works under windows.
* documentation updated for windows.
* filename/line number displayed for range error during signal update.

New in 0.24 (2006-06-25)
* bug fix: correctly handle empty file name.
* bug fix: correctly handle unused subprograms of protected types.
* bug fix: avoid a crash if unused library are use'd.
* bug fix: avoid crashes during error reports.
* bug fix: add a missing case array conversion.
* bug fix: build on x86_64.
* bug fix: code generated for conversion after mod/rem (windows version).
* bug fix: -fexplicit crashed with std.standard functions.
* bug fix: handle recursion of pure/wait checks.
* bug fix: correctly handle error cases of user attributes
* bug fix: time and character read procedure of std.textio.
* bug fix: initialize by value parameters (instead of copy-in).
* Handle enums with more than 256 elements.
* Relax expr static rules in 93c to analyze Xilinx core lib from 8.1
* man page (ghdl.1) added.
* windows installer improved

New in 0.23 (2006-05-16)
* bug fix: handle implicit conversion in resolution functions.
* bug fix: missing implicit conversion added.
* bug fix: avoid a crash in error.

New in 0.22 (2006-03-28)
* direntry added in ghdl.texi
* bug fix: avoid crash if type conversion is indexed/sliced.
* bug fix: do not allow anymore uncomplete individual association
* bug fix: missing check on array association
* bug fix: check bounds for val attribute on enumerated type.
* bug fix: array inequality of locally static expressions evaluated.
* bug fix: configuration issue.
* bug fix: --warn-no-vital-generic is now working.
* Documentation updated (explain bug in Xilinx unisim library).
* Updated to gcc 4.1
* math_real updated.

New in 0.21 (2005-12-18)
* bug fix: line number for some bound violation messages.
* bug fix: improved message error for deferred constants.
* bug fix: file parameter for functions.
* bug fix: universal real divided by integer handled in locally static expr.
* bug fix: std_ulogic types and arrays are known by vpi.
* bug fix: missing space added in VCDs for integers.
* bug fix: CR+LF is also end of line for std.textio.readline.
* bug fix: avoid a crash if parse error on choice.
* bug fix: handle 'image in nested subprograms.
* bug fix: handle 'image for floating point types.
* bug fix: do not use varargs C calls.
* bug fix: handle missing EOL for readline.
* local optimizations (loops, indexed name).
* simulation speed improved by 20% due to processes mngt optimizations.
* stack-switching code ported to x86_64 (amd64/em64t).
* stack-switching code ported to ia64.
* bug fixes for x86_64.
* --syn-binding option extended (see documentation).

New in 0.20 (2005-10-15)
* stack memory usage improved for shortcurt operations.
* gtkwave now displays nice waves for bit and std_ulogic signals.
* time unit is displayed in assert/report message.
* -fexplicit option added.
* integers are now written in VCD files.
* hash table added for design_units (speed optimization).
* range checks slightly optimized.
* --vcdz run time option added.
* improved error message for invalid expressions.
* grt now compiles with GNAT-GPL-2005 (use a GNAT bug work-around).
* bug fix: handle more types for --dump-rti and --wave.
* bug fix: 'last_event and 'last_active (bad value returned when no previous
  event or activity).
* bug fix: 'image attribute for physical types (was bad unit).
* bug fix: 'image attribute for locally static integers.
* bug fix: for reading .ghw files.
* bug fix: in --xref.

New in 0.19 (2005-08-17)
* bug fix: internal error (missing close_temp for implicit read)
* bug fix: --xref-html: avoid to reanalyze unit.
* bug fix: handle implicit conversion for 'image.
* bug fix: aggregate assigned to an aggregate: avoid crash.
* bug fix: array attributes on unconstrained array: avoid crash.
* bug fix: 'last_event returns time'high if no event.
* bug fix: 'last_event on array (uninitialized variable).
* bug fix: allow calling rising_edge with a port of mode buffer.
* bug fix: allow aliases of unconstrained arrays.
* bug fix: bound error on aggregate with an unused other association.
* bug fix: catch indexed/sliced component (was crashing).
* bug fix: catch index/slice of a type conversion (was crashing).
* bug fix: handle bad component specification in conf (was crashing).
* bug fix: missing ports in component (was crashing).
* bug fix: component configurations were dicarded by bug in some cases.
* bug fix: no more unused warnings for subprograms in architectures
  (they may be used in configuration).
* bug fix: allow conversion in component configuration.
* bug fix: conversion in associations with not statically defined array
  signals.
* ADAFLAGS has been replaced by GHDL_ADAFLAGS to ease compilation.
* ieee.math_real and ieee.math_complex added (only partially, based on a
  draft).
* current time is printed with assert/report messages.
* stack switch assembly code ported to powerpc-linux.
* documentation on how to use grt from Ada added.
* allow indexes of indexed names to be non-static in case statements (93c only)
  (this is not standard, but I can't see why it should be required).
* unbound ports of entities are now reported with --warn-binding.
* some error or warning messages improved.
* --wave option added to dump waveforms (using ghw file format).

New in 0.18 (2005-03-12)
* bug fix: in textio.read for time.
* bug fix: file_close does not crash if file was already closed.
* bug fix: spurious unused warnings for protected types.
* bug fix: allow subtype names in slice during sensitivity extraction.
* bug fix: correctly set the default value of collapsed ports.
* bug fix: handling of stack2 (aka large concatenation bug).
* Keep last line number to speed-up line number look-up (improvement).
* --warn-default-binding added, --warn-binding rewritten.
* 'value implemented for integer numbers.

New in 0.17 (2005-02-26)
* command --elab-run added.
* Code generation for aggregate improved.
* bug fix: port map with expression (corner case ?).
* Library name of option --work= is checked.
* bug fix: forbid empty extended identifiers.
* --no-run option added to prevent simulation (may be used to disp tree only).
* disp signal name in error when multiple sources drive an unresolved signal.
* -m/--gen-makefile now handle several libraries.
* dependences are not stored anymore in libraries (shorter/faster).
* bug fix: enumeration literal xrefs.
* mentor version of ieee library is now provided.
* bug fix: non-object name in sensitivity list crashed.
* handling of universal types is more consistent with LRM
  (almost corner cases).
* iterator and indexes whose bounds were universal expressions are now
  of type integer or erroneous, according to the weird LRM rules.
* handle selected name as entity name in architecture/configuration.
* bug fix: correctly handle alias of signals in processes.

New in 0.16 (2005-01-02)
* bug fix: better handling of errors in type conversion.
* bug fix: few uninitialized variables in ghdl itself caught.
* std.textio: readline has no limits on line length.
* bug fix: parse error: 'begin' in aggregates.
* bug fix: bad 'unused subprogram' warnings.
* command -r (run) added.

New in 0.15 (2004-10-13)
* library file format modified to handle relative pathes.
* install fixed to use relative pathes.
* internal change: ortho API modified (constant are not anymore expressions).

New in 0.14 (2004-08-29)
* bug fix: resolution function can be an expanded name.
* bug fix: missing type check in a corner case.
* bug fix: emit an error when EOF is reached while a text file is read.
* bug fix: std.textio.read for negative number.
* bug fix: std.textio.read [integer]: correctly handle end of line.
* bug fix: parameters of protected type: handled and checked.
* bug fix: gen_tree.c modified to work with sparc.
* pretty printing in HTML command (--pp-html) added.
* xref generation in HTML command (--xref-html) added.
* syntax checking command (-s) added.
* Code generation in whole command (-c files -e unit) added.
* warns for unused subprograms.
* bug box added to help bug reports.
* -s (syntax check) command added.
* Missing grt subprogram to close non-text file added.
* maximum line length of std.textio.readline extended to 512 characters.
* std.textio.readline assert error on truncated lines.
* Handle P32 and P64 in --trace-signals
* sequentials statements are not canonicalized (should be faster).
* DESTDIR added in Makefile to ease packaging.
* for -m command, re-parse modified files of the work library.
* Many checks added on interfaces.
* Many checks added on associations, better handling of conversions.
* Checks for unassociated entity ports at elaboration.

New in 0.13 (2004-06-26)
* support of 64bits integers and 32bits time (not yet user available)
* handle 'high and 'low attributes on non-locally static types and subtypes.
* Many warning switches added (to control output of warnings).
* --gen-makefile mode added to ghdl (to generate a Makefile)
* alias identifier restrictions of vhdl-02 implemented.
* declarative region for architecture from vhdl-02 implemented.
* buffer port association rules of vhdl-02 implemented.
* method operator restrictions of vhdl-02 implemented.
* 'driving and 'driving_value implemented.
* run-time bound check error message now contains file name and line number.
* strings are not stored anymore with the identifiers.
* parser does not back-track anymore.
* bug fix: name clash in generated .s files (arch and port/generic names).
* bug fix: implicit conversion of signal parameters.
* bug fix: handle locally static type conversion of arrays.
* bug fix: stabilize during elaboration of an unconstrained signal.
* bug fix: revert previous vhdl87 conf spec bug fix, according to INT-1991
           issue 27.
* bug fix: multiple visibility of declarations (eg: direct and alias).
* bug fix: names attribute of non-object aliases.

New in 0.12 (2004-05-30)
* simulation speed improved (2 fold) due to reduced activity optimization.
* type conversion handled in associations
* make mode of ghdl improved.
* bug fix: attribute specification
* bug fix: allow discrete type marks in choices
* bug fix: handling of generate statement for VCD
* bug fix: allow dereference in variable associations
* bug fix: allow function conversion in block port map
* bug fix: vhdl87: apply configuration specification inside generate stmts.
* bug fix: catch non-passive concurrent procedure calls in entity.
* bug fix: association of an unconstrained port with an expression.
* bug fix: declaring an uncons. array subtype of an uncons. array subtype.

New in 0.11.1 (2004-04-24)
* bug fix: corner case of signal not updated
* bug fix: handle 'stable, 'quiet with a paramater > 0
* bug fix: typos (missing '+ ') in sparc.S

New in 0.11 (2004-04-17)
* bug fix: in code generation for an aggregate.
* bug fix: run-time check of ascending order of projected transactions.
* bug fix: empty sequence of stmts in case alternatives (unidim array).
* bug fix: evaluation of locally static 'range attribute.
* signal collapsing improved.
* simulation kernel speed improved (maybe 5x faster).
* --lines mode of ghdldrv added.
* boolean signals are now dumped in vcd files.
* bug fix: implicit conversion in formal function convertor.
* bug fix: return type is a type mark.

New in 0.10 (2004-02-28)
* architecture with many instances can be compiled with less memory.
* --stats option added to the simulator, to evaluate performance.
* signals are now collapsed between instances, if possible.
* simulation is about 3x faster.
* sparc port available (source only).
* more checks added for attribute specification.
* bug fixed: absolute source files.
* chop command added (split files by design unit).
* bug fixed: empty sequence of statements in case alternatives.

New in 0.9 (2004-02-01)
* VITAL level 0 restrictions checks added.
* VITAL 2000 packages provided.
* run-time information (such as signal names) rewritten.
* SDF support added (partial and experimental).
* bug fixed: allow elaboration even if no package body if the package is
  present in a file but not used by the hierarchy.
* bug fixed: delay_length range is pre-elaborated (was not in v93).
* bug fixed: crashed when a design unit is not found at elaboration.
* bug fixed: allow association of 'stable, 'quiet... with signal interfaces.
* bug fixed: concurrent procedure call creates a non-sensitized process.
* bug fixed: effective value of non-scalar resolved signal might not be set.

New in 0.8 (2003-11-05)
* protected types (from 1076a/1076-2000) implemented.
* file declarations are finalized in subprograms.
* an exit call-back has been added in the run-time library.
* internal modifications (nodes are stored in a table).
* signal declaration not allowed in processes (bug fixed).
* name of generated executable can be set with '-o' option.
* IVI (ivi.sourceforge.org) support through a few VPI subprograms.
* pure and wait checks added.
* out ports are correctly dumped in VCD files.
* several bugs fixed.

New in 0.7 (2003-08-02)
* layout of internal nodes improved.
* incremental binding (vhdl93).
* association of in port with expressions (vhdl93).
* instantiation added in hierarchy (bug fixed).
* individual association of subelements by expression (bug fixed).
* --disp-time option added.
* --stop-delta option is working (bug fixed).
* make mode (ghdl -m) rewritten.
* 'simple_name, 'path_name and 'instance_name added (vhdl93).
* correctly handle operators names at function call (bug fixed).
* several small bugs fixed.

New in 0.6 (2003-06-09)
* internal modifications (single linked list used instead of arrays).
* bug fixed: xnor on bit and boolean is working.
* Mentor version of std_logic_arith is provided.
* postponed handled (vhdl 93).
* declarations allowed in a generate statement (vhdl 93).
* bug fixed: selected_name list in use clauses.
* non object aliases handled (vhdl93).
* signatures handled (vhdl93).
* many other small bug fixes.

New in 0.5 (2003-05-10)
* foreign attribute handled.  You can now call subprograms defined in a foreign
  language (such as C or Ada).
* ghdl entry point added: you can start the VHDL simulation from your own
  program.
* bug fixed: triple use.
* bug fixed: incomplete types

New in 0.4.1 (2003-04-07)
* bug fixed in the vcd output.

New in 0.4 (2003-04-02)
* libgrt does not depend on GNAT library anymore.
  Installation requirements are reduced.
* 'delayed attribute implemented.
* 'transaction attribute implemented.
* unaffected (from vhdl-93) implemented.
* ghdl action '--disp-standard' prints the std.standard package.
* exponentiation operator ("**") implemented for all integer and floating
  point types.
* bug fix: subprogram interfaces are now elaborated.
* many other small bug fixes.