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Development System Reference Guide www.xilinx.com 421
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VHDL
VHDL is an acronym for VHSIC Hardware Description Language
(VHSIC an acronym for Very High-Speed Integrated Circuits). It can
be used to describe the concurrent and sequential behavior of a digital
system at many levels of abstraction ranging from the algorithmic
level to the gate level. VHDL is IEEE standard 1076-1993.
A VHDL file has a .vhd or .vhdl extension.
VITAL
VITAL is an acronym for VHDL Intitiative Toward ASIC Libraries. It
is a VHDL-library standard (IEEE 1076.4) that defines standard
constructs for simulation modeling, accelerating, and improving the
performance of VHDL simulators.
W
wire
A wire is a net or a signal. See net.
X
xtclsh
Xilinx Tcl Shell (xtclsh), which presents the xtclsh prompt used for
running scripts and using the Xilinx Tcl commands.