Syntax

gate_type (drive_strength) #(delay) instance_name [instance_array_range] (terminal, terminal, ... );

switch_type #(delay) instance_name [instance_array_range] (terminal, terminal, ... );

Gate Type		Terminal Order
`and or xor`	`nand nor`xnor	(1_output, 1-or-more_inputs)
`buf`	`not`	(1-or-more_outputs, 1_input)
`bufif0 bufif1`	`notif0 notif1`	(1_output, 1_input, 1_control)
`pullup`	`pulldown`	(1_output)
user-defined-primitives		(1_output, 1-or-more_inputs)

Switch Type		Terminal Order
`pmos nmos`	`rpmos rnmos`	(1_output, 1_input, 1_control)
`cmos`	`rcmos`	(1_output, 1_input, n_control, p_control)
`tran`	`rtran`	(2_bidirectional-inouts)
`tranif0 rtranif0`	`rtranif0 rtranif1`	(2_bidirectional-inouts, 1_control)

Primitive Delay Syntax

#delay or #(delay)
Single delay for all output transitions

#(delay, delay)
Separate delays for (rising, falling) transitions

#(delay, delay, delay)
Separate delays for (rising, falling, turn-off) transitions

#(min_delay:typ_delay:max_delay)
Minimum to maximum range of delays for all transitions

#(min_delay:typ_delay:max_delay, min_delay:typ_delay:max_delay)
Min. to max. range of delays for (rising, falling) transitions

#(min_delay:typ_delay:max_delay, min_delay:typ_delay:max_delay, min_delay:typ_delay:max_delay)
Min. to max. range of delays for (rising, falling, turn-off) transitions

delay (optional) represents the propagation delay through a primitive. The default delay is zero. Integers or real numbers may be used.

strength (optional) is specified as (strength1, strength0) or (strength0, strength1) Refer to Logic Strengths for strength keywords.

Only gate primitives may have drive strength specified. Switch primitives pass the input strength to the output. Resistive switches reduce the strength as it passes through.

instance_name (optional) may used to reference specific primitives in debugging tools, schematics, etc.

instance_array_range (optional) instantiates multiple primitives, each instance connected to separate bits of a vector.

The range is specified as [lhi:rhi] (left-hand-index to right-hand-index).
The primitive instances are connected with the right-most instance index connected to the right-most bit of each vector, and progressing towards the left.
Vector signals must be the same size as the array.
Scalar signals are connected to all instances in the array.

Primitive Instance Examples	Notes
`and i1 (out,in1,in2);`	zero delay gate primitive
`and #5 (o,i1,i2,i3,i4);`	same delay for all transitions
`not #(2,3) u7(out,in);`	separate rise & fall delays
`buf (pull0,strong1)(y,a);`	output drive strengths model ECL
`wire [31:0] y, a; buf #2.7 i[31:0] (y,a);`	array of 32 buffers