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]
31impl<Reg> const Instruction for Rv64ZbkbInstruction<Reg>
32where
33    Reg: [const] Register<Type = u64>,
34{
35    type Reg = Reg;
36
37    #[inline(always)]
38    fn try_decode(instruction: u32) -> Option<Self> {
39        let opcode = (instruction & 0b111_1111) as u8;
40        let rd_bits = ((instruction >> 7) & 0x1f) as u8;
41        let funct3 = ((instruction >> 12) & 0b111) as u8;
42        let rs1_bits = ((instruction >> 15) & 0x1f) as u8;
43        let rs2_bits = ((instruction >> 20) & 0x1f) as u8;
44        let funct7 = ((instruction >> 25) & 0b111_1111) as u8;
45        let funct12 = ((instruction >> 20) & 0xfff) as u16;
46
47        match opcode {
48            // OP-IMM (I-type): brev8
49            0b0010011 => {
50                let rd = Reg::from_bits(rd_bits)?;
51                let rs1 = Reg::from_bits(rs1_bits)?;
52                match funct3 {
53                    // brev8: funct12 = 0b011010000111 = 0x687
54                    0b101 if funct12 == 0b0110_1000_0111 => Some(Self::Brev8 { rd, rs1 }),
55                    _ => None,
56                }
57            }
58            // OP (R-type): pack, packh
59            0b0110011 => {
60                let rd = Reg::from_bits(rd_bits)?;
61                let rs1 = Reg::from_bits(rs1_bits)?;
62                let rs2 = Reg::from_bits(rs2_bits)?;
63                match (funct3, funct7) {
64                    // pack: funct3=100, funct7=0000100
65                    (0b100, 0b0000100) => Some(Self::Pack { rd, rs1, rs2 }),
66                    // packh: funct3=111, funct7=0000100
67                    (0b111, 0b0000100) => Some(Self::Packh { rd, rs1, rs2 }),
68                    _ => None,
69                }
70            }
71            // OP-32 (R-type): packw
72            0b0111011 => {
73                let rd = Reg::from_bits(rd_bits)?;
74                let rs1 = Reg::from_bits(rs1_bits)?;
75                let rs2 = Reg::from_bits(rs2_bits)?;
76                match (funct3, funct7) {
77                    // packw: funct3=100, funct7=0000100, rs2 != 0
78                    // rs2=0 collides with inherited RV64 Zbb zext.h and must fall through.
79                    (0b100, 0b0000100) if rs2_bits != 0 => Some(Self::Packw { rd, rs1, rs2 }),
80                    _ => None,
81                }
82            }
83            _ => None,
84        }
85    }
86
87    #[inline(always)]
88    fn alignment() -> u8 {
89        align_of::<u32>() as u8
90    }
91
92    #[inline(always)]
93    fn size(&self) -> u8 {
94        size_of::<u32>() as u8
95    }
96}
97
98#[instruction]
99impl<Reg> fmt::Display for Rv64ZbkbInstruction<Reg>
100where
101    Reg: fmt::Display + Copy,
102{
103    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
104        match self {
105            Self::Pack { rd, rs1, rs2 } => write!(f, "pack {}, {}, {}", rd, rs1, rs2),
106            Self::Packh { rd, rs1, rs2 } => write!(f, "packh {}, {}, {}", rd, rs1, rs2),
107            Self::Packw { rd, rs1, rs2 } => write!(f, "packw {}, {}, {}", rd, rs1, rs2),
108            Self::Brev8 { rd, rs1 } => write!(f, "brev8 {}, {}", rd, rs1),
109        }
110    }
111}
ab_riscv_primitives/instructions/rv64/zk/zbkb.rs

ab_riscv_primitives/instructions/rv64/zk/
zbkb.rs
