ab_riscv_primitives/instructions/rv64/zk/
zbkb.rs

1//! RV64 Zbkb extension
2
3#[cfg(test)]
4mod tests;
5
6use crate::instructions::Instruction;
7use crate::instructions::rv64::b::zbb::Rv64ZbbInstruction;
8use crate::registers::general_purpose::Register;
9use ab_riscv_macros::instruction;
10use core::fmt;
11
12/// RISC-V RV64 Zbkb instruction (Bit-manipulation for Cryptography)
13#[instruction(
14    reorder = [Andn, Orn, Xnor, Rol, Rolw, Ror, Rori, Roriw, Rorw, Rev8, Pack, Packh, Packw, Brev8],
15    ignore = [Rv64ZbbInstruction],
16    inherit = [Rv64ZbbInstruction],
17)]
18#[derive(Debug, Clone, Copy, PartialEq, Eq)]
19pub enum Rv64ZbkbInstruction<Reg> {
20    /// Pack low 32 bits of `rs1` and `rs2` into `rd`
21    Pack { rd: Reg, rs1: Reg, rs2: Reg },
22    /// Pack low 8 bits of `rs1` and `rs2` into `rd` bytes `0` and `1`
23    Packh { rd: Reg, rs1: Reg, rs2: Reg },
24    /// Pack low 16 bits of `rs1` and `rs2` into lower 32 bits of `rd`, sign-extend
25    Packw { rd: Reg, rs1: Reg, rs2: Reg },
26    /// Reverse bits in each byte of `rs1`
27    Brev8 { rd: Reg, rs1: Reg },
28}
29
30#[instruction]
31const impl<Reg> Instruction for Rv64ZbkbInstruction<Reg>
32where
33    Reg: [const] Register<Type = u64>,
34{
35    type Reg = Reg;
36
37    #[inline(always)]
38    #[cfg_attr(feature = "no-panic", no_panic_const::no_panic(const))]
39    fn try_decode(instruction: u32) -> Option<Self> {
40        let opcode = (instruction & 0b111_1111) as u8;
41        let rd_bits = ((instruction >> 7) & 0x1f) as u8;
42        let funct3 = ((instruction >> 12) & 0b111) as u8;
43        let rs1_bits = ((instruction >> 15) & 0x1f) as u8;
44        let rs2_bits = ((instruction >> 20) & 0x1f) as u8;
45        let funct7 = ((instruction >> 25) & 0b111_1111) as u8;
46        let funct12 = ((instruction >> 20) & 0xfff) as u16;
47
48        match opcode {
49            // OP-IMM (I-type): brev8
50            0b001_0011 => {
51                let rd = Reg::from_bits(rd_bits)?;
52                let rs1 = Reg::from_bits(rs1_bits)?;
53                match funct3 {
54                    // brev8: funct12 = 0b0110_1000_0111 = 0x687
55                    0b101 if funct12 == 0b0110_1000_0111 => Some(Self::Brev8 { rd, rs1 }),
56                    _ => None,
57                }
58            }
59            // OP (R-type): pack, packh
60            0b011_0011 => {
61                let rd = Reg::from_bits(rd_bits)?;
62                let rs1 = Reg::from_bits(rs1_bits)?;
63                let rs2 = Reg::from_bits(rs2_bits)?;
64                match (funct3, funct7) {
65                    // pack: funct3=100, funct7=000_0100
66                    (0b100, 0b000_0100) => Some(Self::Pack { rd, rs1, rs2 }),
67                    // packh: funct3=111, funct7=000_0100
68                    (0b111, 0b000_0100) => Some(Self::Packh { rd, rs1, rs2 }),
69                    _ => None,
70                }
71            }
72            // OP-32 (R-type): packw
73            0b011_1011 => {
74                let rd = Reg::from_bits(rd_bits)?;
75                let rs1 = Reg::from_bits(rs1_bits)?;
76                let rs2 = Reg::from_bits(rs2_bits)?;
77                match (funct3, funct7) {
78                    // packw: funct3=100, funct7=000_0100, rs2 != 0
79                    // rs2=0 collides with inherited RV64 Zbb zext.h and must fall through.
80                    (0b100, 0b000_0100) if rs2_bits != 0 => Some(Self::Packw { rd, rs1, rs2 }),
81                    _ => None,
82                }
83            }
84            _ => None,
85        }
86    }
87
88    #[inline(always)]
89    fn alignment() -> u8 {
90        align_of::<u32>() as u8
91    }
92
93    #[inline(always)]
94    fn size(&self) -> u8 {
95        size_of::<u32>() as u8
96    }
97}
98
99#[instruction]
100impl<Reg> fmt::Display for Rv64ZbkbInstruction<Reg>
101where
102    Reg: fmt::Display + Copy,
103{
104    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
105        match self {
106            Self::Pack { rd, rs1, rs2 } => write!(f, "pack {rd}, {rs1}, {rs2}"),
107            Self::Packh { rd, rs1, rs2 } => write!(f, "packh {rd}, {rs1}, {rs2}"),
108            Self::Packw { rd, rs1, rs2 } => write!(f, "packw {rd}, {rs1}, {rs2}"),
109            Self::Brev8 { rd, rs1 } => write!(f, "brev8 {rd}, {rs1}"),
110        }
111    }
112}
ab_riscv_primitives/instructions/rv64/zk/zbkb.rs

ab_riscv_primitives/instructions/rv64/zk/
zbkb.rs
