ab_riscv_primitives/instructions/
rv32.rs

1//! Base RISC-V RV32 instruction set
2
3pub mod b;
4pub mod c;
5pub mod m;
6#[cfg(test)]
7mod tests;
8pub mod zce;
9pub mod zk;
10
11use crate::instructions::Instruction;
12use crate::instructions::utils::{I24, I24WithZeroedBits};
13use crate::registers::general_purpose::Register;
14use ab_riscv_macros::instruction;
15use core::fmt;
16
17/// RISC-V RV32 instruction
18#[instruction]
19#[derive(Debug, Clone, Copy, PartialEq, Eq)]
20pub enum Rv32Instruction<Reg> {
21    // R-type
22    Add { rd: Reg, rs1: Reg, rs2: Reg },
23    Sub { rd: Reg, rs1: Reg, rs2: Reg },
24    Sll { rd: Reg, rs1: Reg, rs2: Reg },
25    Slt { rd: Reg, rs1: Reg, rs2: Reg },
26    Sltu { rd: Reg, rs1: Reg, rs2: Reg },
27    Xor { rd: Reg, rs1: Reg, rs2: Reg },
28    Srl { rd: Reg, rs1: Reg, rs2: Reg },
29    Sra { rd: Reg, rs1: Reg, rs2: Reg },
30    Or { rd: Reg, rs1: Reg, rs2: Reg },
31    And { rd: Reg, rs1: Reg, rs2: Reg },
32
33    // I-type
34    Addi { rd: Reg, rs1: Reg, imm: i16 },
35    Slti { rd: Reg, rs1: Reg, imm: i16 },
36    Sltiu { rd: Reg, rs1: Reg, imm: i16 },
37    Xori { rd: Reg, rs1: Reg, imm: i16 },
38    Ori { rd: Reg, rs1: Reg, imm: i16 },
39    Andi { rd: Reg, rs1: Reg, imm: i16 },
40    Slli { rd: Reg, rs1: Reg, shamt: u8 },
41    Srli { rd: Reg, rs1: Reg, shamt: u8 },
42    Srai { rd: Reg, rs1: Reg, shamt: u8 },
43
44    // Loads (I-type)
45    Lb { rd: Reg, rs1: Reg, imm: i16 },
46    Lh { rd: Reg, rs1: Reg, imm: i16 },
47    Lw { rd: Reg, rs1: Reg, imm: i16 },
48    Lbu { rd: Reg, rs1: Reg, imm: i16 },
49    Lhu { rd: Reg, rs1: Reg, imm: i16 },
50
51    // Jalr (I-type)
52    Jalr { rd: Reg, rs1: Reg, imm: i16 },
53
54    // S-type
55    Sb { rs2: Reg, rs1: Reg, imm: i16 },
56    Sh { rs2: Reg, rs1: Reg, imm: i16 },
57    Sw { rs2: Reg, rs1: Reg, imm: i16 },
58
59    // B-type
60    Beq { rs1: Reg, rs2: Reg, imm: I24 },
61    Bne { rs1: Reg, rs2: Reg, imm: I24 },
62    Blt { rs1: Reg, rs2: Reg, imm: I24 },
63    Bge { rs1: Reg, rs2: Reg, imm: I24 },
64    Bltu { rs1: Reg, rs2: Reg, imm: I24 },
65    Bgeu { rs1: Reg, rs2: Reg, imm: I24 },
66
67    // Lui (U-type)
68    Lui { rd: Reg, imm: I24WithZeroedBits<12> },
69
70    // Auipc (U-type)
71    Auipc { rd: Reg, imm: I24WithZeroedBits<12> },
72
73    // Jal (J-type)
74    Jal { rd: Reg, imm: I24 },
75
76    // Fence
77    Fence { pred: u8, succ: u8 },
78    FenceTso,
79
80    // System instructions
81    Ecall,
82    Ebreak,
83
84    // Unimplemented/illegal
85    Unimp,
86}
87
88#[instruction]
89impl<Reg> const Instruction for Rv32Instruction<Reg>
90where
91    Reg: [const] Register<Type = u32>,
92{
93    type Reg = Reg;
94
95    #[inline(always)]
96    fn try_decode(instruction: u32) -> Option<Self> {
97        let opcode = (instruction & 0b111_1111) as u8;
98        let rd_bits = ((instruction >> 7) & 0x1f) as u8;
99        let funct3 = ((instruction >> 12) & 0b111) as u8;
100        let rs1_bits = ((instruction >> 15) & 0x1f) as u8;
101        let rs2_bits = ((instruction >> 20) & 0x1f) as u8;
102        let funct7 = ((instruction >> 25) & 0b111_1111) as u8;
103
104        match opcode {
105            // R-type
106            0b011_0011 => {
107                let rd = Reg::from_bits(rd_bits)?;
108                let rs1 = Reg::from_bits(rs1_bits)?;
109                let rs2 = Reg::from_bits(rs2_bits)?;
110                match (funct3, funct7) {
111                    (0b000, 0b000_0000) => Some(Self::Add { rd, rs1, rs2 }),
112                    (0b000, 0b010_0000) => Some(Self::Sub { rd, rs1, rs2 }),
113                    (0b001, 0b000_0000) => Some(Self::Sll { rd, rs1, rs2 }),
114                    (0b010, 0b000_0000) => Some(Self::Slt { rd, rs1, rs2 }),
115                    (0b011, 0b000_0000) => Some(Self::Sltu { rd, rs1, rs2 }),
116                    (0b100, 0b000_0000) => Some(Self::Xor { rd, rs1, rs2 }),
117                    (0b101, 0b000_0000) => Some(Self::Srl { rd, rs1, rs2 }),
118                    (0b101, 0b010_0000) => Some(Self::Sra { rd, rs1, rs2 }),
119                    (0b110, 0b000_0000) => Some(Self::Or { rd, rs1, rs2 }),
120                    (0b111, 0b000_0000) => Some(Self::And { rd, rs1, rs2 }),
121                    _ => None,
122                }
123            }
124            // I-type
125            0b001_0011 => {
126                let rd = Reg::from_bits(rd_bits)?;
127                let rs1 = Reg::from_bits(rs1_bits)?;
128                let imm = (instruction.cast_signed() >> 20) as i16;
129                match funct3 {
130                    0b000 => Some(Self::Addi { rd, rs1, imm }),
131                    0b010 => Some(Self::Slti { rd, rs1, imm }),
132                    0b011 => Some(Self::Sltiu { rd, rs1, imm }),
133                    0b100 => Some(Self::Xori { rd, rs1, imm }),
134                    0b110 => Some(Self::Ori { rd, rs1, imm }),
135                    0b111 => Some(Self::Andi { rd, rs1, imm }),
136                    0b001 => {
137                        // RV32: 5-bit shamt, funct7 must be 0b0000000
138                        let shamt = (instruction >> 20) as u8 & 0b1_1111;
139                        if funct7 == 0b000_0000 {
140                            Some(Self::Slli { rd, rs1, shamt })
141                        } else {
142                            None
143                        }
144                    }
145                    0b101 => {
146                        // RV32: 5-bit shamt, funct7 distinguishes SRLI/SRAI
147                        let shamt = (instruction >> 20) as u8 & 0b1_1111;
148                        match funct7 {
149                            0b000_0000 => Some(Self::Srli { rd, rs1, shamt }),
150                            0b010_0000 => Some(Self::Srai { rd, rs1, shamt }),
151                            _ => None,
152                        }
153                    }
154                    _ => None,
155                }
156            }
157            // Loads (I-type)
158            0b000_0011 => {
159                let rd = Reg::from_bits(rd_bits)?;
160                let rs1 = Reg::from_bits(rs1_bits)?;
161                let imm = (instruction.cast_signed() >> 20) as i16;
162                match funct3 {
163                    0b000 => Some(Self::Lb { rd, rs1, imm }),
164                    0b001 => Some(Self::Lh { rd, rs1, imm }),
165                    0b010 => Some(Self::Lw { rd, rs1, imm }),
166                    0b100 => Some(Self::Lbu { rd, rs1, imm }),
167                    0b101 => Some(Self::Lhu { rd, rs1, imm }),
168                    _ => None,
169                }
170            }
171            // Jalr (I-type)
172            0b110_0111 => {
173                let rd = Reg::from_bits(rd_bits)?;
174                let rs1 = Reg::from_bits(rs1_bits)?;
175                if funct3 == 0b000 {
176                    let imm = (instruction.cast_signed() >> 20) as i16;
177                    Some(Self::Jalr { rd, rs1, imm })
178                } else {
179                    None
180                }
181            }
182            // S-type
183            0b010_0011 => {
184                let rs1 = Reg::from_bits(rs1_bits)?;
185                let rs2 = Reg::from_bits(rs2_bits)?;
186                let imm11_5 = ((instruction >> 25) & 0b111_1111).cast_signed();
187                let imm4_0 = ((instruction >> 7) & 0b1_1111).cast_signed();
188                let imm = (imm11_5 << 5) | imm4_0;
189                // Sign extend
190                let imm = ((imm << 20) >> 20) as i16;
191                match funct3 {
192                    0b000 => Some(Self::Sb { rs2, rs1, imm }),
193                    0b001 => Some(Self::Sh { rs2, rs1, imm }),
194                    0b010 => Some(Self::Sw { rs2, rs1, imm }),
195                    _ => None,
196                }
197            }
198            // B-type
199            0b110_0011 => {
200                let rs1 = Reg::from_bits(rs1_bits)?;
201                let rs2 = Reg::from_bits(rs2_bits)?;
202                let imm12 = ((instruction >> 31) & 1).cast_signed();
203                let imm10_5 = ((instruction >> 25) & 0b11_1111).cast_signed();
204                let imm4_1 = ((instruction >> 8) & 0b1111).cast_signed();
205                let imm11 = ((instruction >> 7) & 1).cast_signed();
206                let imm = (imm12 << 12) | (imm11 << 11) | (imm10_5 << 5) | (imm4_1 << 1);
207                // Sign extend
208                let imm = I24::from_i32((imm << 19) >> 19);
209                match funct3 {
210                    0b000 => Some(Self::Beq { rs1, rs2, imm }),
211                    0b001 => Some(Self::Bne { rs1, rs2, imm }),
212                    0b100 => Some(Self::Blt { rs1, rs2, imm }),
213                    0b101 => Some(Self::Bge { rs1, rs2, imm }),
214                    0b110 => Some(Self::Bltu { rs1, rs2, imm }),
215                    0b111 => Some(Self::Bgeu { rs1, rs2, imm }),
216                    _ => None,
217                }
218            }
219            // Lui (U-type)
220            0b011_0111 => {
221                let rd = Reg::from_bits(rd_bits)?;
222                let imm = I24WithZeroedBits::from_i32((instruction & 0xffff_f000).cast_signed());
223                Some(Self::Lui { rd, imm })
224            }
225            // Auipc (U-type)
226            0b001_0111 => {
227                let rd = Reg::from_bits(rd_bits)?;
228                let imm = I24WithZeroedBits::from_i32((instruction & 0xffff_f000).cast_signed());
229                Some(Self::Auipc { rd, imm })
230            }
231            // Jal (J-type)
232            0b110_1111 => {
233                let rd = Reg::from_bits(rd_bits)?;
234                let imm20 = ((instruction >> 31) & 1).cast_signed();
235                let imm10_1 = ((instruction >> 21) & 0b11_1111_1111).cast_signed();
236                let imm11 = ((instruction >> 20) & 1).cast_signed();
237                let imm19_12 = ((instruction >> 12) & 0b1111_1111).cast_signed();
238                let imm = (imm20 << 20) | (imm19_12 << 12) | (imm11 << 11) | (imm10_1 << 1);
239                // Sign extend
240                let imm = I24::from_i32((imm << 11) >> 11);
241                Some(Self::Jal { rd, imm })
242            }
243            // Fence (I-type like, simplified for EM)
244            0b000_1111 => {
245                if funct3 == 0b000 && rd_bits == 0 && rs1_bits == 0 {
246                    let fm = (instruction >> 28) & 0b1111;
247                    let pred = ((instruction >> 24) & 0xf) as u8;
248                    let succ = ((instruction >> 20) & 0xf) as u8;
249                    match fm {
250                        0b0000 => Some(Self::Fence { pred, succ }),
251                        0b1000 => {
252                            // FENCE.TSO: fm=8, pred=RW(0b0011), succ=RW(0b0011) - fixed by spec
253                            if pred == 0b0011 && succ == 0b0011 {
254                                Some(Self::FenceTso)
255                            } else {
256                                None
257                            }
258                        }
259                        _ => None,
260                    }
261                } else {
262                    None
263                }
264            }
265            // System instructions
266            0b111_0011 => {
267                let imm = (instruction >> 20) & 0xfff;
268                if funct3 == 0 && rd_bits == 0 && rs1_bits == 0 {
269                    match imm {
270                        0 => Some(Self::Ecall),
271                        1 => Some(Self::Ebreak),
272                        _ => None,
273                    }
274                } else if funct3 == 0b001 && rd_bits == 0 && rs1_bits == 0 && imm == 0xc00 {
275                    // `0xc000_1073` is emitted as `unimp`/illegal instruction by various compilers,
276                    // including Rust when it hits a panic
277                    Some(Self::Unimp)
278                } else {
279                    None
280                }
281            }
282            _ => None,
283        }
284    }
285
286    #[inline(always)]
287    fn alignment() -> u8 {
288        align_of::<u32>() as u8
289    }
290
291    #[inline(always)]
292    fn size(&self) -> u8 {
293        size_of::<u32>() as u8
294    }
295}
296
297#[instruction]
298impl<Reg> fmt::Display for Rv32Instruction<Reg>
299where
300    Reg: fmt::Display,
301{
302    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
303        match self {
304            Self::Add { rd, rs1, rs2 } => write!(f, "add {rd}, {rs1}, {rs2}"),
305            Self::Sub { rd, rs1, rs2 } => write!(f, "sub {rd}, {rs1}, {rs2}"),
306            Self::Sll { rd, rs1, rs2 } => write!(f, "sll {rd}, {rs1}, {rs2}"),
307            Self::Slt { rd, rs1, rs2 } => write!(f, "slt {rd}, {rs1}, {rs2}"),
308            Self::Sltu { rd, rs1, rs2 } => write!(f, "sltu {rd}, {rs1}, {rs2}"),
309            Self::Xor { rd, rs1, rs2 } => write!(f, "xor {rd}, {rs1}, {rs2}"),
310            Self::Srl { rd, rs1, rs2 } => write!(f, "srl {rd}, {rs1}, {rs2}"),
311            Self::Sra { rd, rs1, rs2 } => write!(f, "sra {rd}, {rs1}, {rs2}"),
312            Self::Or { rd, rs1, rs2 } => write!(f, "or {rd}, {rs1}, {rs2}"),
313            Self::And { rd, rs1, rs2 } => write!(f, "and {rd}, {rs1}, {rs2}"),
314
315            Self::Addi { rd, rs1, imm } => write!(f, "addi {rd}, {rs1}, {imm}"),
316            Self::Slti { rd, rs1, imm } => write!(f, "slti {rd}, {rs1}, {imm}"),
317            Self::Sltiu { rd, rs1, imm } => write!(f, "sltiu {rd}, {rs1}, {imm}"),
318            Self::Xori { rd, rs1, imm } => write!(f, "xori {rd}, {rs1}, {imm}"),
319            Self::Ori { rd, rs1, imm } => write!(f, "ori {rd}, {rs1}, {imm}"),
320            Self::Andi { rd, rs1, imm } => write!(f, "andi {rd}, {rs1}, {imm}"),
321            Self::Slli { rd, rs1, shamt } => write!(f, "slli {rd}, {rs1}, {shamt}"),
322            Self::Srli { rd, rs1, shamt } => write!(f, "srli {rd}, {rs1}, {shamt}"),
323            Self::Srai { rd, rs1, shamt } => write!(f, "srai {rd}, {rs1}, {shamt}"),
324
325            Self::Lb { rd, rs1, imm } => write!(f, "lb {rd}, {imm}({rs1})"),
326            Self::Lh { rd, rs1, imm } => write!(f, "lh {rd}, {imm}({rs1})"),
327            Self::Lw { rd, rs1, imm } => write!(f, "lw {rd}, {imm}({rs1})"),
328            Self::Lbu { rd, rs1, imm } => write!(f, "lbu {rd}, {imm}({rs1})"),
329            Self::Lhu { rd, rs1, imm } => write!(f, "lhu {rd}, {imm}({rs1})"),
330
331            Self::Jalr { rd, rs1, imm } => write!(f, "jalr {rd}, {imm}({rs1})"),
332
333            Self::Sb { rs2, rs1, imm } => write!(f, "sb {rs2}, {imm}({rs1})"),
334            Self::Sh { rs2, rs1, imm } => write!(f, "sh {rs2}, {imm}({rs1})"),
335            Self::Sw { rs2, rs1, imm } => write!(f, "sw {rs2}, {imm}({rs1})"),
336
337            Self::Beq { rs1, rs2, imm } => write!(f, "beq {rs1}, {rs2}, {imm}"),
338            Self::Bne { rs1, rs2, imm } => write!(f, "bne {rs1}, {rs2}, {imm}"),
339            Self::Blt { rs1, rs2, imm } => write!(f, "blt {rs1}, {rs2}, {imm}"),
340            Self::Bge { rs1, rs2, imm } => write!(f, "bge {rs1}, {rs2}, {imm}"),
341            Self::Bltu { rs1, rs2, imm } => write!(f, "bltu {rs1}, {rs2}, {imm}"),
342            Self::Bgeu { rs1, rs2, imm } => write!(f, "bgeu {rs1}, {rs2}, {imm}"),
343
344            Self::Lui { rd, imm } => write!(f, "lui {rd}, 0x{:x}", imm.to_i32() >> 12),
345
346            Self::Auipc { rd, imm } => write!(f, "auipc {rd}, 0x{:x}", imm.to_i32() >> 12),
347
348            Self::Jal { rd, imm } => write!(f, "jal {rd}, {imm}"),
349
350            Self::Fence { pred, succ } => write!(f, "fence {pred}, {succ}"),
351            Self::FenceTso => write!(f, "fence.tso"),
352
353            Self::Ecall => write!(f, "ecall"),
354            Self::Ebreak => write!(f, "ebreak"),
355
356            Self::Unimp => write!(f, "unimp"),
357        }
358    }
359}
ab_riscv_primitives/instructions/rv32.rs

ab_riscv_primitives/instructions/
rv32.rs
