Primitives

XST supports certain gate level primitives. The supported syntax is as follows:

gate_type instance_name (output, inputs, ...);

The following example shows Gate Level Primitive Instantiations.

and U1 (out, in1, in2);

bufif1 U2 (triout, data, trienable);

The following table shows which primitives are supported.

Table 7-11: Primitives

Gate Level Primitives	and nand nor or xnor xor	Supported
	buf not	Supported
	bufif0 bufif1 notif0 notif1	Supported
	pulldown pullup	Unsupported
	drive strength	Ignored
	delay	Ignored
	array of primitives	Supported
Switch Level Primitives	cmos nmos pmos rcmos rnmos rpmos	Unsupported
	rtran rtranif0 rtranif1 tran tranif0 tranif1	Unsupported
User Defined Primitives		Unsupported