Language Support Tables

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The following tables indicate which Verilog constructs are supported in XST. Previous sections in this chapter describe these constructs and their use within XST.

Note XST does not allow underscores as the first character of signal names (for example, _DATA_1).

Table 7-3 Constants

Integer Constants	Supported
Real Constants	Unsupported
Strings Constants	Unsupported

Table 7-4 Data Types

Nets	net type	wire	Supported
		tri	Supported
		supply0, supply1	Supported
		wand, wor, triand, trior	Supported
		tri0, tri1, trireg	Unsupported
	drive strength		Ignored
Registers	reg		Supported
	integer		Supported
	real		Unsupported
	realtime		Unsupported
Vectors	net		Supported
	reg		Supported
	vectored		Supported
	scalared		Supported
Memories			Supported
Parameters			Supported
Named Events			Unsupported

Table 7-5 Continuous Assignments

Drive Strength	Ignored
Delay	Ignored

Table 7-6 Procedural Assignments

Blocking Assignments		Supported
Non-Blocking Assignments		Supported
Continuous Procedural Assignments	assign	Supported with limitations See the "Assign and Deassign Statements" section
	deassign
	force	Unsupported
	release	Unsupported
if Statement	if, if else	Supported
case Statement	case, casex, casez	Supported
forever Statement		Unsupported
repeat Statement		Supported (repeat value must be constant)
while Statement		Unsupported
for Statement		Supported (bounds must be static)
fork/join Statement		Unsupported
Timing Control on Procedural Assignments	delay (#)	Ignored
	event (@)	Unsupported
	wait	Unsupported
	named events	Unsupported
Sequential Blocks		Supported
Parallel Blocks		Unsupported
Specify Blocks		Ignored
initial Statement		Ignored
always Statement		Supported
task		Supported (Recursion Unsupported)
functions		Supported (Recursion Unsupported)
disable Statement		Unsupported

Table 7-7 System Tasks and Functions

System Tasks	Ignored
System Functions	Unsupported

Table 7-8 Design Hierarchy

Module definition	Supported
Macromodule definition	Unsupported
Hierarchical names	Unsupported
defparam	Supported
Array of instances	Unsupported

Table 7-9 Compiler Directives

`celldefine `endcelldefine	Ignored
`default_nettype	Ignored
`define	Supported
`undef	Unsupported
`ifdef `else `endif	Supported
`include	Supported
`resetall	Ignored
`timescale	Ignored
`unconnected_drive `nounconnected_drive	Ignored
`uselib	Unsupported