bug: AUIPC instruction not properly decoded

[pandaninjas]

Test case

use raki::{BaseIOpcode, Decode, Instruction, Isa, OpcodeKind};

fn example() {
    let inst_bytes: u32 = 0x00001597;
    let inst: Instruction = match inst_bytes.decode(Isa::Rv64) {
        Ok(inst) => inst,
        Err(e) => panic!("decoding failed due to {e:?}"),
    };
    println!("{inst}"); // auipc a1, 0x1000
}

rvcodec.js reports that it is supposed to be aiupc a1, 0x1, https://luplab.gitlab.io/rvcodecjs/#q=0x00001597&abi=false&isa=AUTO

[pandaninjas]

It seems like it depends on the interpretation of the intermediate value. It's represented shifted left by 12 bits, and needs to be shifted right by 12 bits before being used.

[Alignof]

Thank you for reporting this issue.
I was able to reproduce and confirm the behavior you described using both rvcodec.js and GNU objdump.
As you pointed out, it should be shifted left by 12 bits, and needs to be shifted right by user (NOT library).

raki/src/decode/base_i.rs

Line 276 in 754a26e

let U_type = || (inst.slice(31, 12) << 12) as i32;

I'll work on a fix to correct the immediate decoding logic in the library and post an update on this issue once the changes have been pushed.

[Alignof]

@pandaninjas
I've fixed this issue in #41 and released v1.3.2.
Thank you again for your report.
Please feel free to let me know if you find anything else.