Editing RISC-V (section)

==Immediate Encoding==
"There are a further two variants of the instruction formats (SB/UJ) based on the handling of
immediates" - Spec 2.3

"The only difference between the S and SB formats is that the 12-bit immediate field is used to encode
branch offsets in multiples of 2 in the SB format. Instead of shifting all bits in the instruction-
encoded immediate left by one in hardware as is conventionally done, the middle bits (imm[10:1]) and sign bit stay in fixed positions, while the lowest bit in S format (inst[7]) encodes a high-order
bit in SB format."

"Similarly, the only difference between the U and UJ formats is that the 20-bit immediate is shifted
left by 12 bits to form U immediates and by 1 bit to form J immediates. The location of instruction
bits in the U and UJ format immediates is chosen to maximize overlap with the other formats and
with each other."

"Integer computational instructions are either encoded as register-immediate operations using
the I-type format or as register-register operations using the R-type format."