ab_riscv_interpreter/rv32/
m.rs

1//! RV32 M extension
2
3#[cfg(test)]
4mod tests;
5pub mod zmmul;
6
7use crate::{ExecutableInstruction, ExecutionError, InterpreterState};
8use ab_riscv_macros::instruction_execution;
9use ab_riscv_primitives::instructions::rv32::m::Rv32MInstruction;
10use ab_riscv_primitives::registers::general_purpose::Register;
11use core::ops::ControlFlow;
12
13#[instruction_execution]
14impl<Reg, ExtState, Memory, PC, InstructionHandler, CustomError>
15    ExecutableInstruction<
16        InterpreterState<Reg, ExtState, Memory, PC, InstructionHandler, CustomError>,
17        CustomError,
18    > for Rv32MInstruction<Reg>
19where
20    Reg: Register<Type = u32>,
21    [(); Reg::N]:,
22{
23    #[inline(always)]
24    fn execute(
25        self,
26        state: &mut InterpreterState<Reg, ExtState, Memory, PC, InstructionHandler, CustomError>,
27    ) -> Result<ControlFlow<()>, ExecutionError<Reg::Type, CustomError>> {
28        match self {
29            Self::Mul { rd, rs1, rs2 } => {
30                let value = state.regs.read(rs1).wrapping_mul(state.regs.read(rs2));
31                state.regs.write(rd, value);
32            }
33            Self::Mulh { rd, rs1, rs2 } => {
34                // Signed × signed: widen to i64, take upper 32 bits
35                let (_lo, prod) = state
36                    .regs
37                    .read(rs1)
38                    .cast_signed()
39                    .widening_mul(state.regs.read(rs2).cast_signed());
40                state.regs.write(rd, prod.cast_unsigned());
41            }
42            Self::Mulhsu { rd, rs1, rs2 } => {
43                // Signed × unsigned: widen to i64, take upper 32 bits
44                let prod =
45                    i64::from(state.regs.read(rs1).cast_signed()) * i64::from(state.regs.read(rs2));
46                let value = prod >> 32;
47                state.regs.write(rd, value.cast_unsigned() as u32);
48            }
49            Self::Mulhu { rd, rs1, rs2 } => {
50                // Unsigned × unsigned: widen to u64, take upper 32 bits
51                let prod = u64::from(state.regs.read(rs1)) * u64::from(state.regs.read(rs2));
52                let value = prod >> 32;
53                state.regs.write(rd, value as u32);
54            }
55            Self::Div { rd, rs1, rs2 } => {
56                let dividend = state.regs.read(rs1).cast_signed();
57                let divisor = state.regs.read(rs2).cast_signed();
58                let value = if divisor == 0 {
59                    -1i32
60                } else if dividend == i32::MIN && divisor == -1 {
61                    i32::MIN
62                } else {
63                    dividend / divisor
64                };
65                state.regs.write(rd, value.cast_unsigned());
66            }
67            Self::Divu { rd, rs1, rs2 } => {
68                let dividend = state.regs.read(rs1);
69                let divisor = state.regs.read(rs2);
70                let value = dividend.checked_div(divisor).unwrap_or(u32::MAX);
71                state.regs.write(rd, value);
72            }
73            Self::Rem { rd, rs1, rs2 } => {
74                let dividend = state.regs.read(rs1).cast_signed();
75                let divisor = state.regs.read(rs2).cast_signed();
76                let value = if divisor == 0 {
77                    dividend
78                } else if dividend == i32::MIN && divisor == -1 {
79                    0
80                } else {
81                    dividend % divisor
82                };
83                state.regs.write(rd, value.cast_unsigned());
84            }
85            Self::Remu { rd, rs1, rs2 } => {
86                let dividend = state.regs.read(rs1);
87                let divisor = state.regs.read(rs2);
88                let value = if divisor == 0 {
89                    dividend
90                } else {
91                    dividend % divisor
92                };
93                state.regs.write(rd, value);
94            }
95        }
96
97        Ok(ControlFlow::Continue(()))
98    }
99}
ab_riscv_interpreter/rv32/m.rs

ab_riscv_interpreter/rv32/
m.rs
