README.md, index, WhatIsVHDL, WhatIsGHDL ready for review.

Add shortcuts for shields in a single file and include it where used.
Create base64 GitHub and Travis-CI logos with b64.io and add them to self-created shields. Replace gitter with shield.io's variant.
Start rewriting <Contributing>

1 files changed, 366 insertions, 368 deletions

diff --git a/NEWS.md b/NEWS.md
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@@ -1,440 +1,438 @@
-# NEWS for ghdl (Dunoon Edition)
-
 **v0.34-dev**
-* Display stack backtraces on errors or assert failures
-* Compile scripts for vendor libraries (Xilinx, Altera, osvvm, vunit)
-* Use SSE2 for mcode backend
-* Mode backend ported to `x86_64`
-* Support cocotb [potentialventures/cocotb](https://github.com/potentialventures/cocotb)
-* Main repository is now on github: [github.com/tgingold/ghdl](https://github.com/tgingold/ghdl)
-* Docs available on rtd: [ghdl.readthedocks.org](https://ghdl.readthedocs.org/en/latest/)
-* Speed improved.
-* New option `--psl-report`, to report status of PSL assert and cover.
-* VHDL2008: support nested packages
+- Display stack backtraces on errors or assert failures
+- Compile scripts for vendor libraries (Xilinx, Altera, osvvm, vunit)
+- Use SSE2 for mcode backend
+- Mode backend ported to `x86_64`
+- Support cocotb [potentialventures/cocotb](https://github.com/potentialventures/cocotb)
+- Main repository is now on github: [github.com/tgingold/ghdl](https://github.com/tgingold/ghdl)
+- Docs available on rtd: [ghdl.readthedocks.org](https://ghdl.readthedocs.org/en/latest/)
+- Speed improved.
+- New option `--psl-report`, to report status of PSL assert and cover.
+- VHDL2008: support nested packages
 
 **v0.33** (2015-10-04)
-* Improve support of VHDL2008
-* Support [OSVVM](http://osvvm.org) 2015
-* Support VUnit: [LarsAsplund/vunit](https://github.com/LarsAsplund/vunit)
-* Many bugs fixed
+- Improve support of VHDL2008
+- Support [OSVVM](http://osvvm.org) 2015
+- Support VUnit: [LarsAsplund/vunit](https://github.com/LarsAsplund/vunit)
+- Many bugs fixed
 
 **v0.32** (2014-11-XX)
-* Updated to build with `gcc-4.9.2`.
-* support:
-	* partial of VHDL2008 (available with `--std=08`):
-	* new `std.env` package.
-	* added features in `std.textio` package
-	* all standard IEEE packages.
-	* new operations (relation operators, maximum and minimum, unary reduction operators)
-	* `boolean_vector`, `integer_vector`, `real_vector`.
-	* process(all).
-	* generic packages and interface package declarations.
-	* block comments (aka delimited comments)
-	* implicitely defined to_string functions.
-	* OSVVM 2014_01
-* Bugs fixed
+- Updated to build with `gcc-4.9.2`.
+- support:
+	- partial of VHDL2008 (available with `--std=08`):
+	- new `std.env` package.
+	- added features in `std.textio` package
+	- all standard IEEE packages.
+	- new operations (relation operators, maximum and minimum, unary reduction operators)
+	- `boolean_vector`, `integer_vector`, `real_vector`.
+	- process(all).
+	- generic packages and interface package declarations.
+	- block comments (aka delimited comments)
+	- implicitely defined to_string functions.
+	- OSVVM 2014_01
+- Bugs fixed
 
 **v0.31** (2014-01-XX)
-* Updated to build with `gcc-4.8.2`.
-* Supports OSVVM (Open-Source VHDL Verification Methodology) (see [osvvm.org](http://osvvm.org)) in its VHDL-2002 form.
-* Adds `'image` and `'value` attributes for all required datatypes
-* Many bugs and support issues fixed.
-* New home on `https://sourceforge.net/projects/ghdl-updates/`
+- Updated to build with `gcc-4.8.2`.
+- Supports OSVVM (Open-Source VHDL Verification Methodology) (see [osvvm.org](http://osvvm.org)) in its VHDL-2002 form.
+- Adds `'image` and `'value` attributes for all required datatypes
+- Many bugs and support issues fixed.
+- New home on `https://sourceforge.net/projects/ghdl-updates/`
 
 **v0.30**
 Never released, swith to Dunoon Edition.
 
 **v0.29** (2010-01-09)
-* Initial implementation of embedded PSL assertions.
-* Improve:
-	* speed of non-sensitized processes.
-	* speed of string case statement (dichotomy instead of linear search).
-* bug fix:
-	* and improvements in SDF annotator.
-	* when the bound of a string literal type is not locally static.
-	* gcov crash
+- Initial implementation of embedded PSL assertions.
+- Improve:
+	- speed of non-sensitized processes.
+	- speed of string case statement (dichotomy instead of linear search).
+- bug fix:
+	- and improvements in SDF annotator.
+	- when the bound of a string literal type is not locally static.
+	- gcov crash
 
 **v0.28** (2009-09-17)
-* Add `--std=08` to enable VHDL2008 features.
-* Support all-sensitized processes from VHDL2008.
-* Documentation typos (thanks to Peter Huewe).
-* bug fix:
-  * handle `'pos/'leftof/'rightof/'succ/'pred` in concurrent statements.
-  * overloaded resolution functions.
-  * direct drivers elaboration for unconstrained array signals.
-  * many minor bugs.
+- Add `--std=08` to enable VHDL2008 features.
+- Support all-sensitized processes from VHDL2008.
+- Documentation typos (thanks to Peter Huewe).
+- bug fix:
+  - handle `'pos/'leftof/'rightof/'succ/'pred` in concurrent statements.
+  - overloaded resolution functions.
+  - direct drivers elaboration for unconstrained array signals.
+  - many minor bugs.
 
 **v0.27** (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
-  * crash during elaboration for top entities with ports/generic
-  * crash when string literal in aggregate.
-  * concatenation with an array subtype element.
-  * non-static subtype used by type conversions in associations.
-  * clear timeout in wait for.
-  * minor bugs.
+- Improve SDF annotation (handles much more annotations)
+- Add `--ieee-asserts=` option to control assert messages from ieee packages.
+- bug fix:
+  - aliases in port map
+  - crash during elaboration for top entities with ports/generic
+  - crash when string literal in aggregate.
+  - concatenation with an array subtype element.
+  - non-static subtype used by type conversions in associations.
+  - clear timeout in wait for.
+  - minor bugs.
 
 **v0.26** (2007-04-08)
-* `GHDL_PREFIX` environment variable overrides default installation prefix.
-* simulation speed improved with 'direct drivers'.
-* windows version:
-	* exceptions are caught
-	* use executable path instead of registry for prefix
-* bug fix:
-	* individual association by expression (was not working)
-	* individual association of string
-	* within windows code generator
-	* [windows] large local variables crashed
-	* crash when overloaded aggregate target.
-	* forbid individual association with open
-	* crash when bad array prefix
-	* correctly extract sensitivity of record aggregate
+- `GHDL_PREFIX` environment variable overrides default installation prefix.
+- simulation speed improved with 'direct drivers'.
+- windows version:
+	- exceptions are caught
+	- use executable path instead of registry for prefix
+- bug fix:
+	- individual association by expression (was not working)
+	- individual association of string
+	- within windows code generator
+	- [windows] large local variables crashed
+	- crash when overloaded aggregate target.
+	- forbid individual association with open
+	- crash when bad array prefix
+	- correctly extract sensitivity of record aggregate
 
 **v0.25** (2006-08-11)
-* 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.
-* bug fix: 
-	* ieee math libraries available when `--ieee=synopsys`.
-	* `'image` in package bodies.
-	* scan of fp literals.
-	* interface identifier is checked for conformance rules.
-	* avoid a crash in case of error in configuration specification.
-	* non-static choice in unidim case are now correctly checked.
-	* do not crash in case of bad use of incomplete type.
-	* `'range` are not expressions.
-	* handle file declaration in concurrent procedure calls.
-	* correctly handle static `'image` attribute.
-	* handle in-conversion for signal associated with an expression.
-	* 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.
+- bug fix: 
+	- ieee math libraries available when `--ieee=synopsys`.
+	- `'image` in package bodies.
+	- scan of fp literals.
+	- interface identifier is checked for conformance rules.
+	- avoid a crash in case of error in configuration specification.
+	- non-static choice in unidim case are now correctly checked.
+	- do not crash in case of bad use of incomplete type.
+	- `'range` are not expressions.
+	- handle file declaration in concurrent procedure calls.
+	- correctly handle static `'image` attribute.
+	- handle in-conversion for signal associated with an expression.
+	- emit an error when a function tries to exit without a return.
 
 **v0.24** (2006-06-25)
-* 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
-* bug fix:
-	* correctly handle empty file name.
-	* correctly handle unused subprograms of protected types.
-	* avoid a crash if unused library are used.
-	* avoid crashes during error reports.
-	* add a missing case array conversion.
-	* build on `x86_64`.
-	* code generated for conversion after mod/rem (windows version).
-	* `-fexplicit` crashed with `std.standard` functions.
-	* handle recursion of pure/wait checks.
-	* correctly handle error cases of user attributes
-	* time and character read procedure of std.textio.
-	* 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
+- bug fix:
+	- correctly handle empty file name.
+	- correctly handle unused subprograms of protected types.
+	- avoid a crash if unused library are used.
+	- avoid crashes during error reports.
+	- add a missing case array conversion.
+	- build on `x86_64`.
+	- code generated for conversion after mod/rem (windows version).
+	- `-fexplicit` crashed with `std.standard` functions.
+	- handle recursion of pure/wait checks.
+	- correctly handle error cases of user attributes
+	- time and character read procedure of std.textio.
+	- initialize by value parameters (instead of copy-in).
 
 **v0.23** (2006-05-16)
-* bug fix:
-	* handle implicit conversion in resolution functions.
-	* missing implicit conversion added.
-	* avoid a crash in error.
+- bug fix:
+	- handle implicit conversion in resolution functions.
+	- missing implicit conversion added.
+	- avoid a crash in error.
 
 **v0.22** (2006-03-28)
-* direntry added in `ghdl.texi`
-* updated:
-	* Documentation (explain bug in Xilinx unisim library).
-	* to `gcc 4.1`
-	* math_real
-* bug fix:
-	* avoid crash if type conversion is indexed/sliced
-	* do not allow anymore uncomplete individual association
-	* missing check on array association
-	* check bounds for val attribute on enumerated type
-	* array inequality of locally static expressions evaluated
-	* configuration issue
-	* `--warn-no-vital-generic` is now working
+- direntry added in `ghdl.texi`
+- updated:
+	- Documentation (explain bug in Xilinx unisim library).
+	- to `gcc 4.1`
+	- math_real
+- bug fix:
+	- avoid crash if type conversion is indexed/sliced
+	- do not allow anymore uncomplete individual association
+	- missing check on array association
+	- check bounds for val attribute on enumerated type
+	- array inequality of locally static expressions evaluated
+	- configuration issue
+	- `--warn-no-vital-generic` is now working
 
 **v0.21** (2005-12-18)
-* 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`.
-* `--syn-binding` option extended (see documentation).
-* bug fix:
-	* line number for some bound violation messages.
-	* improved message error for deferred constants.
-	* file parameter for functions.
-	* universal real divided by integer handled in locally static expr.
-	* `std_ulogic` types and arrays are known by VPI.
-	* missing space added in VCDs for integers.
-	* `CR+LF` is also end of line for `std.textio.readline`.
-	* avoid a crash if parse error on choice.
-	* handle `'image` in nested subprograms.
-	* handle `'image` for floating point types.
-	* do not use varargs C calls.
-	* handle missing `EOL` for `readline`.
-	* for `x86_64`
+- 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`.
+- `--syn-binding` option extended (see documentation).
+- bug fix:
+	- line number for some bound violation messages.
+	- improved message error for deferred constants.
+	- file parameter for functions.
+	- universal real divided by integer handled in locally static expr.
+	- `std_ulogic` types and arrays are known by VPI.
+	- missing space added in VCDs for integers.
+	- `CR+LF` is also end of line for `std.textio.readline`.
+	- avoid a crash if parse error on choice.
+	- handle `'image` in nested subprograms.
+	- handle `'image` for floating point types.
+	- do not use varargs C calls.
+	- handle missing `EOL` for `readline`.
+	- for `x86_64`
 
 **v0.20** (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`.
-	* `'last_event` and `'last_active` (bad value returned when no previous event or activity).
-	* `'image` attribute for physical types (was bad unit).
-	* `'image` attribute for locally static integers.
-	* for reading `.ghw` files.
-	* in `--xref`.
+- 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`.
+	- `'last_event` and `'last_active` (bad value returned when no previous event or activity).
+	- `'image` attribute for physical types (was bad unit).
+	- `'image` attribute for locally static integers.
+	- for reading `.ghw` files.
+	- in `--xref`.
 
 **v0.19** (2005-08-17)
-* `ADAFLAGS` has been replaced by `GHDL_ADAFLAGS` to ease compilation.
-* `ieee.math_real` and `ieee.math_complex` added (only partially, based on a
+- `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)
+- 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).
-* bug fix:
-	* internal error (missing close_temp for implicit read)
-	* `--xref-html`: avoid to reanalyze unit.
-	* handle implicit conversion for `'image`.
-	* aggregate assigned to an aggregate: avoid crash.
-	* array attributes on unconstrained array: avoid crash.
-	* `'last_event` returns `time'high` if no event.
-	* `'last_event` on array (uninitialized variable).
-	* allow calling `rising_edge` with a port of mode buffer.
-	* allow aliases of unconstrained arrays.
-	* bound error on aggregate with an unused other association.
-	* catch indexed/sliced component (was crashing).
-	* catch index/slice of a type conversion (was crashing).
-	* handle bad component specification in conf (was crashing).
-	* missing ports in component (was crashing).
-	* component configurations were dicarded by bug in some cases.
-	* no more unused warnings for subprograms in architectures (they may be used in configuration).
-	* allow conversion in component configuration.
-	* conversion in associations with not statically defined array signals.
+- 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).
+- bug fix:
+	- internal error (missing close_temp for implicit read)
+	- `--xref-html`: avoid to reanalyze unit.
+	- handle implicit conversion for `'image`.
+	- aggregate assigned to an aggregate: avoid crash.
+	- array attributes on unconstrained array: avoid crash.
+	- `'last_event` returns `time'high` if no event.
+	- `'last_event` on array (uninitialized variable).
+	- allow calling `rising_edge` with a port of mode buffer.
+	- allow aliases of unconstrained arrays.
+	- bound error on aggregate with an unused other association.
+	- catch indexed/sliced component (was crashing).
+	- catch index/slice of a type conversion (was crashing).
+	- handle bad component specification in conf (was crashing).
+	- missing ports in component (was crashing).
+	- component configurations were dicarded by bug in some cases.
+	- no more unused warnings for subprograms in architectures (they may be used in configuration).
+	- allow conversion in component configuration.
+	- conversion in associations with not statically defined array signals.
 
 **v0.18** (2005-03-12)
-* Keep last line number to speed-up line number look-up (improvement).
-* `--warn-default-binding` added, `--warn-binding` rewritten.
-* `'value` implemented for integer numbers.
-* bug fix:
-	* in `textio.read` for time.
-	* `file_close` does not crash if file was already closed.
-	* spurious unused warnings for protected types.
-	* allow subtype names in slice during sensitivity extraction.
-	* correctly set the default value of collapsed ports.
-	* 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.
+- bug fix:
+	- in `textio.read` for time.
+	- `file_close` does not crash if file was already closed.
+	- spurious unused warnings for protected types.
+	- allow subtype names in slice during sensitivity extraction.
+	- correctly set the default value of collapsed ports.
+	- handling of stack2 (aka large concatenation bug).
 
 **v0.17** (2005-02-26)
-* command `--elab-run` added.
-* Code generation for aggregate improved.
-* Library name of option `--work=` is checked.
-* `--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).
-* mentor version of ieee library is now provided.
-* 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:
-	* port map with expression (corner case ?).
-	* forbid empty extended identifiers.
-	* enumeration literal xrefs.
-	* non-object name in sensitivity list crashed.
-	* correctly handle alias of signals in processes.
+- command `--elab-run` added.
+- Code generation for aggregate improved.
+- Library name of option `--work=` is checked.
+- `--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).
+- mentor version of ieee library is now provided.
+- 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:
+	- port map with expression (corner case ?).
+	- forbid empty extended identifiers.
+	- enumeration literal xrefs.
+	- non-object name in sensitivity list crashed.
+	- correctly handle alias of signals in processes.
 
 **v0.16** (2005-01-02)
-* `std.textio`: readline has no limits on line length.
-* command `-r` (run) added.
-* bug fix:
-	* better handling of errors in type conversion.
-	* few uninitialized variables in ghdl itself caught.
-	* parse error: `begin` in aggregates.
-	* bad `unused subprogram` warnings.
+- `std.textio`: readline has no limits on line length.
+- command `-r` (run) added.
+- bug fix:
+	- better handling of errors in type conversion.
+	- few uninitialized variables in ghdl itself caught.
+	- parse error: `begin` in aggregates.
+	- bad `unused subprogram` warnings.
 
 **v0.15** (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).
+- library file format modified to handle relative pathes.
+- install fixed to use relative pathes.
+- internal change: ortho API modified (constant are not anymore expressions).
 
 **v0.14** (2004-08-29)
-* 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.
-* bug fix:
-	* resolution function can be an expanded name.
-	* missing type check in a corner case.
-	* emit an error when `EOF` is reached while a text file is read.
-	* `std.textio.read` for negative number.
-	* `std.textio.read` [integer]: correctly handle end of line.
-	* parameters of protected type: handled and checked.
-	* `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.
+- bug fix:
+	- resolution function can be an expanded name.
+	- missing type check in a corner case.
+	- emit an error when `EOF` is reached while a text file is read.
+	- `std.textio.read` for negative number.
+	- `std.textio.read` [integer]: correctly handle end of line.
+	- parameters of protected type: handled and checked.
+	- `gen_tree.c` modified to work with sparc.
 
 **v0.13** (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).
-	* implicit conversion of signal parameters.
-	* handle locally static type conversion of arrays.
-	* stabilize during elaboration of an unconstrained signal.
-	* revert previous `vhdl87` conf spec bug fix, according to INT-1991 issue 27.
-	* multiple visibility of declarations (eg: direct and alias).
-	* names attribute of non-object aliases.
+- 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).
+	- implicit conversion of signal parameters.
+	- handle locally static type conversion of arrays.
+	- stabilize during elaboration of an unconstrained signal.
+	- revert previous `vhdl87` conf spec bug fix, according to INT-1991 issue 27.
+	- multiple visibility of declarations (eg: direct and alias).
+	- names attribute of non-object aliases.
 
 **v0.12** (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
-	* allow discrete type marks in choices
-	* handling of generate statement for VCD
-	* allow dereference in variable associations
-	* allow function conversion in block port map
-	* vhdl87: apply configuration specification inside generate stmts.
-	* catch non-passive concurrent procedure calls in entity.
-	* association of an unconstrained port with an expression.
-	* declaring an uncons. array subtype of an uncons. array subtype.
+- simulation speed improved (2 fold) due to reduced activity optimization.
+- type conversion handled in associations
+- make mode of ghdl improved.
+- bug fix:
+	- attribute specification
+	- allow discrete type marks in choices
+	- handling of generate statement for VCD
+	- allow dereference in variable associations
+	- allow function conversion in block port map
+	- vhdl87: apply configuration specification inside generate stmts.
+	- catch non-passive concurrent procedure calls in entity.
+	- association of an unconstrained port with an expression.
+	- declaring an uncons. array subtype of an uncons. array subtype.
 
 **v0.11.1** (2004-04-24)
-* bug fix:
-	* corner case of signal not updated
-	* handle `'stable`, `'quiet` with a paramater > 0
-	* typos (missing `+ `) in sparc.S
+- bug fix:
+	- corner case of signal not updated
+	- handle `'stable`, `'quiet` with a paramater > 0
+	- typos (missing `+ `) in sparc.S
 
 **v0.11** (2004-04-17)
-* 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:
-	* in code generation for an aggregate.
-	* run-time check of ascending order of projected transactions.
-	* empty sequence of stmts in case alternatives (unidim array).
-	* evaluation of locally static 'range attribute.
-	* implicit conversion in formal function convertor.
-	* return type is a type mark.
+- 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:
+	- in code generation for an aggregate.
+	- run-time check of ascending order of projected transactions.
+	- empty sequence of stmts in case alternatives (unidim array).
+	- evaluation of locally static 'range attribute.
+	- implicit conversion in formal function convertor.
+	- return type is a type mark.
 
 **v0.10** (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.
-* chop command added (split files by design unit).
-* bug fix:
-	* absolute source files.
-	* empty sequence of statements in case alternatives.
+- 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.
+- chop command added (split files by design unit).
+- bug fix:
+	- absolute source files.
+	- empty sequence of statements in case alternatives.
 
 **v0.9** (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 fix:
-	* allow elaboration even if no package body if the package is present in a file but not used by the hierarchy.
-	* `delay_length` range is pre-elaborated (was not in v93).
-	* crashed when a design unit is not found at elaboration.
-	* allow association of `'stable`, `'quiet`... with signal interfaces.
-	* concurrent procedure call creates a non-sensitized process.
-	* effective value of non-scalar resolved signal might not be set.
+- 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 fix:
+	- allow elaboration even if no package body if the package is present in a file but not used by the hierarchy.
+	- `delay_length` range is pre-elaborated (was not in v93).
+	- crashed when a design unit is not found at elaboration.
+	- allow association of `'stable`, `'quiet`... with signal interfaces.
+	- concurrent procedure call creates a non-sensitized process.
+	- effective value of non-scalar resolved signal might not be set.
 
 **v0.8** (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).
-* 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.
-* bug fix:
-	* signal declaration not allowed in processes.
-	* several bugs fixed.
+- 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).
+- 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.
+- bug fix:
+	- signal declaration not allowed in processes.
+	- several bugs fixed.
 
 **v0.7** (2003-08-02)
-* layout of internal nodes improved.
-* incremental binding (vhdl93).
-* association of in port with expressions (vhdl93).
-* `--disp-time` option added.
-* make mode (`ghdl -m`) rewritten.
-* `'simple_name`, `'path_name` and `'instance_name` added (vhdl93).
-* bug fix:
-	* instantiation added in hierarchy.
-	* individual association of subelements by expression.
-	* `--stop-delta` option is working.
-	* correctly handle operators names at function call.
-	* several small bugs fixed.
+- layout of internal nodes improved.
+- incremental binding (vhdl93).
+- association of in port with expressions (vhdl93).
+- `--disp-time` option added.
+- make mode (`ghdl -m`) rewritten.
+- `'simple_name`, `'path_name` and `'instance_name` added (vhdl93).
+- bug fix:
+	- instantiation added in hierarchy.
+	- individual association of subelements by expression.
+	- `--stop-delta` option is working.
+	- correctly handle operators names at function call.
+	- several small bugs fixed.
 
 **v0.6** (2003-06-09)
-* internal modifications (single linked list used instead of arrays).
-* Mentor version of std_logic_arith is provided.
-* postponed handled (vhdl 93).
-* declarations allowed in a generate statement (vhdl 93).
-* non object aliases handled (vhdl93).
-* signatures handled (vhdl93).
-* bug fix:
-	* `xnor` on `bit` and `boolean` is working.
-	* `selected_name` list in use clauses.
-	* many other small bug fixes.
+- internal modifications (single linked list used instead of arrays).
+- Mentor version of std_logic_arith is provided.
+- postponed handled (vhdl 93).
+- declarations allowed in a generate statement (vhdl 93).
+- non object aliases handled (vhdl93).
+- signatures handled (vhdl93).
+- bug fix:
+	- `xnor` on `bit` and `boolean` is working.
+	- `selected_name` list in use clauses.
+	- many other small bug fixes.
 
 **v0.5** (2003-05-10)
-* foreign attribute handled.  You can now call subprograms defined in a foreign
+- 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
+- ghdl entry point added: you can start the VHDL simulation from your own
   program.
-* bug fix:
-	* triple use.
-	* incomplete types
+- bug fix:
+	- triple use.
+	- incomplete types
 
 **v0.4.1** (2003-04-07)
-* bug fix: in the vcd output.
+- bug fix: in the vcd output.
 
 **v0.4** (2003-04-02)
-* `libgrt` does not depend on GNAT library anymore.
+- `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
+- `'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.
-* many other small bug fixes.
-* bug fix: subprogram interfaces are now elaborated.
+- many other small bug fixes.
+- bug fix: subprogram interfaces are now elaborated.