Priority Encoder (if/else)

Procedural blocks (always @(*) for combinational logic) let you describe behavior using imperative constructs like if/else, unlike continuous assignments. A priority encoder is a natural example: it reports the position of the highest-priority active input, and cascaded if/else naturally expresses “priority”.

Build a circuit with a 4-bit input in and a 2-bit output pos. pos should hold the index of the most-significant bit of in that is set to 1. If in is all zeros, pos should be 0.

Interface

Signal	Direction	Width	Description
`in`	input	4	Input bits, priority is `in[3]` highest, `in[0]` lowest
`pos`	output	2	Index of highest-priority set bit (0 if `in == 0`)

Examples

in	pos	Reasoning
`4'b0000`	0	No bits set, default to 0
`4'b0001`	0	Only bit 0 set
`4'b0110`	2	Bit 2 is the highest set bit
`4'b1111`	3	Bit 3 is the highest set bit

Notes

Use always @(*) for a combinational block, and declare pos as output reg (procedural assignments require a reg-type target in Verilog).
Check in[3] first, then in[2], then in[1]: whichever is 1 first “wins” thanks to the if/else if chain.