Originally posted by Umair.ms
I think by 32 bits mean that a single instruction can have an operator and operand (combined) of upto 32 bits.
Absolutely! But in agreement to AES, remember, "smaller is faster". More registers also means an increase of clock cycle time. The current ISA uses 32 registers based on this principle.
On a more general note and as an aside, bit patterns are ambiguous. For example, 10011 could mean 35, -13 in 2's complement representation, or the opcode to declare an R-type MIPS instruction. In other words, bit patterns are arbitrary. It's the implementation that gives them meaning.