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GHDL options

Besides the options described below, GHDL passes any unknown options to the GCC compiler. Thus you can set debugging or optimizations options decribed in the GCC manual.

--work=NAME

Specify the name of the WORK library. Analyzed units are always placed in the library logically named WORK. With this option, you can set its name. By default, the name is work.

VHDL rules forbides you to add units in the std library. Furthermode, you should not put units in the ieee library.

--workdir=PATH

Specify the directory where the WORK library is. When this option is not present, the WORK library is in the current directory. The object files created by the compiler are always placed in the same directory as the WORK library.

--std=STD

Specify the standard to use. By default, the standard is 93c, which means VHDL-93 accepting VHDL-87 syntax. For details on STD values see VHDL standards.

--ieee=VER

Select the IEEE library to use. VER must be one of:

none

Do not supply an IEEE library. Any library clause with the IEEE identifier will fail, unless you have created by your own a library with the IEEE name.

standard

Supply an IEEE library containing only packages defined by IEEE standards. Currently, there are the multivalue logic system packages std_logic_1164 defined by IEEE 1164, the synthesis packages , numeric_bit and numeric_std defined by IEEE 1076.3, and the VITAL packages vital_timing and vital_primitives, defined by IEEE 1076.4. The version of these packages is defined by the VHDL standard used. See VITAL packages, for more details.

synopsys

Supply the former packages and the following additionnal packages: std_logic_arith, std_logic_signed, std_logic_unsigned, std_logic_textio. These packages were created by some companies, and are popular. However they are not standard packages, and have been placed in the IEEE library without the IEEE permission.

mentor

Supply the standardr packages and the following additionnal package: std_logic_arith. The package is a slight variation on a definitly not standard but widely mis-used package.

To avoid errors, you must use the same IEEE library for all units of your design, and during elaboration.

-PPATH

Add PATH to the end of the list of directories to be searched for library files.

The WORK library is always searched in the path specified by the --workdir= option, or in the current directory if the later option is not specified.

--no-vital-checks

--vital-checks

Disable or enable checks of restriction on VITAL units. Checks are enabled by default.

Checks are performed only when a design unit is decorated by a VITAL attribute. The VITAL attributes are VITAL_Level0 and VITAL_Level1, both declared in the ieee.VITAL_Timing package.

Currently, VITAL checks are only partially implemented. See VHDL restrictions for VITAL, for more details.

-Wc,OPTION

Pass OPTION as an option to the compiler.

-Wa,OPTION

Pass OPTION as an option to the assembler.

-Wl,OPTION

Pass OPTION as an option to the linker.

--GHDL1=COMMAND

Use COMMAND as the command name for the compiler. If COMMAND is not a path, then it is search in the list of program directories.

-v

Be verbose. For example, for analysis, elaboration and make mode, GHDL displays the commands executed.