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use isa;
use binary::{Binary};
use memory::{Memory};
pub struct Simulator {
num_cores: usize,
memory: Memory,
}
#[derive(Clone)]
struct RegisterFile {
registers: [u32; 32],
}
#[derive(Clone)]
struct Core {
pc: usize,
registers: RegisterFile,
}
impl RegisterFile {
fn new() -> RegisterFile {
RegisterFile {
registers: [0; 32],
}
}
fn write_word<T: Into<isa::Register>>(&mut self, reg: T, value: u32) {
// TODO: should be safe to use unchecked index
let reg = reg.into();
if reg == isa::Register::X0 { return; }
self.registers[reg.as_num()] = value;
}
fn read_word<T: Into<isa::Register>>(&mut self, reg: T) -> u32 {
self.registers[reg.into().as_num()]
}
}
impl Simulator {
pub fn new(num_cores: usize, binary: Binary) -> Simulator {
let memory = Memory::new(0x2000, binary);
// TODO: initialize GP, registers (GP is in headers)
Simulator {
num_cores: num_cores,
memory: memory,
}
}
pub fn run(&mut self) {
let mut cores = vec![Core { pc: 0x10000, registers: RegisterFile::new() }; self.num_cores];
cores[0].registers.write_word(isa::Register::X3, 0x10860);
loop {
for core in cores.iter_mut() {
self.step_core(core);
}
}
}
fn step_core(&mut self, core: &mut Core) {
if let Some(inst) = self.memory.read_instruction(core.pc) {
match inst.opcode() {
isa::opcodes::BRANCH => {
},
isa::opcodes::INTEGER_IMMEDIATE => match inst.funct3() {
isa::funct3::ADDI => {
let imm = inst.i_imm();
let src: i32 = core.registers.read_word(inst.rs1()) as i32;
core.registers.write_word(inst.rd(), src.wrapping_add(imm) as u32);
println!("After ADDI: {:?} = 0x{:X}", inst.rd(), core.registers.read_word(inst.rd()) as i32);
}
_ => {
panic!("Invalid integer-immediate funct3code: 0x{:x}", inst.funct3());
}
},
isa::opcodes::LOAD => match inst.funct3() {
isa::funct3::LW => {
let imm = inst.i_imm();
let base = core.registers.read_word(inst.rs1());
let address = ((base as i32) + imm) as usize;
if let Some(value) = self.memory.read_word(address) {
core.registers.write_word(inst.rd(), value);
println!("Load to {:?}: 0x{:X}", inst.rd(), value);
}
// TODO: trap
}
_ => {
panic!("Invalid load funct3code: 0x{:x}", inst.funct3());
}
},
isa::opcodes::STORE => match inst.funct3() {
isa::funct3::SW => {
println!("SW");
}
_ => {
panic!("Invalid store funct3code: 0x{:x}", inst.funct3());
}
},
_ => {
panic!("Invalid opcode: 0x{:02X}", inst.opcode());
}
}
}
else {
// trap
}
core.pc += 4;
}
}
|
