Question about pic18 instruction set

[krpz]

i have a question about pic18 instruction set. Why we need 16bits instruction set even thought pic18 have only 75 instrutions ?

 

[Pommie]

There may be only 75 instructions but each instruction takes up a large area of the available instruction space.

For example,

BSF Reg,N,B

Can have Reg from 0 to 256, N from 0 to 7 and B as 0 or 1.

That's a total of 12 bits that are variable in the one instruction. So BSF has 4096 variations.

Mike.