cpu/crates/cpu/tests/next_pc.rs

1558 lines
50 KiB
Rust

// SPDX-License-Identifier: LGPL-3.0-or-later
// See Notices.txt for copyright information
use cpu::{
config::{CpuConfig, UnitConfig},
next_pc::{
CallStackOp, DecodeToPostDecodeInterface, DecodeToPostDecodeInterfaceInner,
FETCH_BLOCK_ID_WIDTH, NextPcToFetchInterface, NextPcToFetchInterfaceInner,
PostDecodeOutputInterface, RetireToNextPcInterface, RetireToNextPcInterfaceInner,
RetireToNextPcInterfacePerInsn, WipDecodedInsn, WipDecodedInsnKind, next_pc,
},
unit::UnitKind,
util::array_vec::ArrayVec,
};
use fayalite::{
intern::{Intern, Interned},
prelude::*,
sim::vcd::VcdWriterDecls,
util::{DebugAsDisplay, RcWriter},
};
use std::{
cell::Cell,
collections::{BTreeMap, BTreeSet, VecDeque},
fmt,
num::NonZeroUsize,
ops::Range,
u64,
};
macro_rules! make_regs {
(
$($Name:ident = $value:literal,)*
) => {
#[derive(Copy, Clone, Debug, Hash, PartialEq, Eq, PartialOrd, Ord)]
#[allow(dead_code)]
enum MockReg {
$($Name = $value,)*
}
impl MockReg {
const REGS: [Self; [$(Self::$Name),*].len()] = [$(Self::$Name),*];
}
const _: () = {
let mut i = 0;
while i < MockReg::REGS.len() {
// verify the values are correct
assert!(i == MockReg::REGS[i] as usize);
i += 1;
}
};
};
}
make_regs! {
Zero = 0,
R1 = 1,
R2 = 2,
R3 = 3,
R4 = 4,
R5 = 5,
R6 = 6,
R7 = 7,
}
#[derive(Clone, Hash, PartialEq, Eq)]
struct MockRegs([u64; MockReg::REGS.len()]);
impl fmt::Debug for MockRegs {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let mut debug_map = f.debug_map();
for reg in MockReg::REGS {
debug_map.entry(&reg, &format_args!("{:#x}", self.read(reg)));
}
debug_map.finish()
}
}
impl MockRegs {
fn new() -> Self {
Self([0; _])
}
fn write(&mut self, reg: MockReg, value: u64) {
match reg {
MockReg::Zero => {
// writing to the zero reg does nothing
}
MockReg::R1
| MockReg::R2
| MockReg::R3
| MockReg::R4
| MockReg::R5
| MockReg::R6
| MockReg::R7 => self.0[reg as usize] = value,
}
}
fn read(&self, reg: MockReg) -> u64 {
self.0[reg as usize]
}
}
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
#[allow(dead_code)]
enum MockIntCmp {
Eq,
Ne,
Ult,
Ule,
Ugt,
Uge,
Slt,
Sle,
Sgt,
Sge,
}
impl MockIntCmp {
fn cmp(self, lhs_u: u64, rhs_u: u64) -> bool {
let lhs_s = lhs_u as i64;
let rhs_s = rhs_u as i64;
match self {
MockIntCmp::Eq => lhs_u == rhs_u,
MockIntCmp::Ne => lhs_u != rhs_u,
MockIntCmp::Ult => lhs_u < rhs_u,
MockIntCmp::Ule => lhs_u <= rhs_u,
MockIntCmp::Ugt => lhs_u > rhs_u,
MockIntCmp::Uge => lhs_u >= rhs_u,
MockIntCmp::Slt => lhs_s < rhs_s,
MockIntCmp::Sle => lhs_s <= rhs_s,
MockIntCmp::Sgt => lhs_s > rhs_s,
MockIntCmp::Sge => lhs_s >= rhs_s,
}
}
}
#[derive(Copy, Clone, PartialEq, Eq, Hash)]
#[allow(dead_code)]
enum MockInsn {
ReadInputByte {
dest: MockReg,
},
WriteOutputByte {
src: MockReg,
},
AddI {
dest: MockReg,
src: MockReg,
immediate: u64,
},
Jump {
target: u64,
},
BrCond {
target: u64,
cond: MockIntCmp,
lhs: MockReg,
rhs: MockReg,
},
BrCondI {
target: u64,
cond: MockIntCmp,
lhs: MockReg,
rhs: u64,
},
Call {
target: u64,
},
Ret,
ExitSysCall,
Illegal,
}
impl fmt::Debug for MockInsn {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
macro_rules! u64_hex {
($v:expr) => {
&format_args!("{:#x}", $v)
};
}
match self {
Self::ReadInputByte { dest } => {
f.debug_struct("ReadInputByte").field("dest", dest).finish()
}
Self::WriteOutputByte { src } => {
f.debug_struct("WriteOutputByte").field("src", src).finish()
}
Self::AddI {
dest,
src,
immediate,
} => f
.debug_struct("AddI")
.field("dest", dest)
.field("src", src)
.field("immediate", u64_hex!(immediate))
.finish(),
Self::Jump { target } => f
.debug_struct("Jump")
.field("target", u64_hex!(target))
.finish(),
Self::BrCond {
target,
cond,
lhs,
rhs,
} => f
.debug_struct("BrCond")
.field("target", u64_hex!(target))
.field("cond", cond)
.field("lhs", lhs)
.field("rhs", rhs)
.finish(),
Self::BrCondI {
target,
cond,
lhs,
rhs,
} => f
.debug_struct("BrCondI")
.field("target", u64_hex!(target))
.field("cond", cond)
.field("lhs", lhs)
.field("rhs", u64_hex!(rhs))
.finish(),
Self::Call { target } => f
.debug_struct("Call")
.field("target", u64_hex!(target))
.finish(),
Self::Ret => write!(f, "Ret"),
Self::ExitSysCall => write!(f, "ExitSysCall"),
Self::Illegal => write!(f, "Illegal"),
}
}
}
impl MockInsn {
fn byte_len(self) -> u64 {
// TODO: change later
4 // all instructions are 4 bytes long for now
}
const READ_INPUT_REG_EOF: u64 = u64::MAX;
fn targets_mut(&mut self) -> impl Iterator<Item = &mut u64> {
match self {
MockInsn::ReadInputByte { .. }
| MockInsn::WriteOutputByte { .. }
| MockInsn::Ret
| MockInsn::ExitSysCall
| MockInsn::Illegal
| MockInsn::AddI { .. } => None,
MockInsn::Jump { target }
| MockInsn::BrCond { target, .. }
| MockInsn::BrCondI { target, .. }
| MockInsn::Call { target } => Some(target),
}
.into_iter()
}
#[hdl]
fn wip_decoded_insn_kind(self) -> SimValue<WipDecodedInsnKind> {
match self {
MockInsn::ReadInputByte { .. }
| MockInsn::WriteOutputByte { .. }
| MockInsn::AddI { .. } =>
{
#[hdl(sim)]
WipDecodedInsnKind::NonBranch()
}
MockInsn::Jump { target } =>
{
#[hdl(sim)]
WipDecodedInsnKind::Branch(target)
}
MockInsn::BrCond { target, .. } | MockInsn::BrCondI { target, .. } =>
{
#[hdl(sim)]
WipDecodedInsnKind::BranchCond(target)
}
MockInsn::Call { target } =>
{
#[hdl(sim)]
WipDecodedInsnKind::Call(target)
}
MockInsn::Ret =>
{
#[hdl(sim)]
WipDecodedInsnKind::Ret()
}
MockInsn::ExitSysCall =>
{
#[hdl(sim)]
WipDecodedInsnKind::Call(EXIT_PC)
}
MockInsn::Illegal =>
{
#[hdl(sim)]
WipDecodedInsnKind::Interrupt(DEMO_ILLEGAL_INSN_TRAP)
}
}
}
#[hdl]
fn call_stack_op(self, pc: u64) -> SimValue<CallStackOp> {
match self {
MockInsn::ReadInputByte { .. }
| MockInsn::WriteOutputByte { .. }
| MockInsn::AddI { .. }
| MockInsn::Jump { .. }
| MockInsn::BrCond { .. }
| MockInsn::BrCondI { .. }
| MockInsn::Illegal =>
{
#[hdl(sim)]
CallStackOp::None()
}
MockInsn::Call { .. } | MockInsn::ExitSysCall =>
{
#[hdl(sim)]
CallStackOp::Push(pc.wrapping_add(self.byte_len()))
}
MockInsn::Ret =>
{
#[hdl(sim)]
CallStackOp::Pop()
}
}
}
}
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
struct MockMachineState {
reset_at_exit: bool,
call_stack: Vec<u64>,
orig_input: &'static [u8],
input: &'static [u8],
output: Vec<u8>,
regs: MockRegs,
pc: u64,
insns: MockInsns,
}
/// match Microwatt's reset PC
const RESET_PC: u64 = 0;
const EXIT_PC: u64 = u64::from_be_bytes(*b"ExitExit");
impl MockMachineState {
fn new(insns: MockInsns, input: impl AsRef<[u8]>, reset_at_exit: bool) -> Self {
let input = Interned::into_inner(input.as_ref().intern());
Self {
reset_at_exit,
call_stack: Vec::with_capacity(16),
orig_input: input,
input,
output: Vec::with_capacity(16),
regs: MockRegs::new(),
pc: RESET_PC,
insns,
}
}
fn reset(&mut self) {
let Self {
reset_at_exit: _,
call_stack,
orig_input,
input,
output,
regs,
pc,
insns: _,
} = self;
call_stack.clear();
*input = *orig_input;
output.clear();
*regs = MockRegs::new();
*pc = RESET_PC;
}
fn run_one(&mut self, trace: bool) -> RetireSeqEntry {
let orig_pc = self.pc;
let insn = self
.insns
.insns
.get(&self.pc)
.copied()
.unwrap_or(MockInsn::Illegal);
if trace {
println!("{orig_pc:#x}: {insn:?}");
}
let mut next_pc = self.pc.wrapping_add(insn.byte_len());
let mut cond_br_taken = None;
let mut cond_br = |target: u64, cond: MockIntCmp, lhs: u64, rhs: u64| {
let taken = cond.cmp(lhs, rhs);
cond_br_taken = Some(taken);
if taken {
next_pc = target;
}
};
let reg = |reg| {
let retval = self.regs.read(reg);
if trace {
println!("read: {reg:?} -> {retval:#x}");
}
retval
};
let write_reg = |this: &mut Self, reg, value| {
if trace {
println!("write: {reg:?} <- {value:#x}");
}
this.regs.write(reg, value);
};
match insn {
MockInsn::ReadInputByte { dest } => {
let value = self
.input
.split_off_first()
.copied()
.map(u64::from)
.unwrap_or(MockInsn::READ_INPUT_REG_EOF);
write_reg(self, dest, value);
}
MockInsn::WriteOutputByte { src } => self.output.push(reg(src) as u8),
MockInsn::AddI {
dest,
src,
immediate,
} => {
let value = reg(src).wrapping_add(immediate);
write_reg(self, dest, value);
}
MockInsn::Jump { target } => next_pc = target,
MockInsn::BrCond {
target,
cond,
lhs,
rhs,
} => cond_br(target, cond, reg(lhs), reg(rhs)),
MockInsn::BrCondI {
target,
cond,
lhs,
rhs,
} => cond_br(target, cond, reg(lhs), rhs),
MockInsn::Call { target } => {
self.call_stack.push(next_pc);
next_pc = target;
}
MockInsn::Ret => next_pc = self.call_stack.pop().unwrap_or(DEMO_ILLEGAL_INSN_TRAP),
MockInsn::ExitSysCall => {
if self.reset_at_exit {
self.reset();
return RetireSeqEntry {
pc: orig_pc,
cond_br_taken: None,
insn,
};
} else {
next_pc = EXIT_PC;
}
}
MockInsn::Illegal => next_pc = DEMO_ILLEGAL_INSN_TRAP,
}
self.pc = next_pc;
RetireSeqEntry {
pc: orig_pc,
cond_br_taken,
insn,
}
}
fn run_until_exit(&mut self, limit: u64, trace: bool) -> Result<u64, String> {
for _ in 0..limit {
let v = self.run_one(trace);
match v.insn {
MockInsn::ExitSysCall => return Ok(self.regs.read(MockReg::R1)),
MockInsn::Illegal => return Err(format!("illegal instruction at {:#x}", v.pc)),
_ => {}
}
}
Err(format!("reached instruction count limit at {:#x}", self.pc))
}
}
#[derive(Copy, Clone, Debug)]
struct RetireSeqEntry {
pc: u64,
cond_br_taken: Option<bool>,
insn: MockInsn,
}
#[derive(Clone)]
struct RetireSeq(MockMachineState);
impl RetireSeq {
fn new(mock_machine: MockMachineState) -> Self {
Self(mock_machine)
}
}
impl Iterator for RetireSeq {
type Item = RetireSeqEntry;
fn next(&mut self) -> Option<Self::Item> {
Some(self.0.run_one(false))
}
}
#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
struct MockInsns {
insns: Interned<BTreeMap<u64, MockInsn>>,
}
impl MockInsns {
fn fetch_block(&self, pc_range: std::ops::Range<u64>) -> impl Iterator<Item = (u64, MockInsn)> {
self.insns
.range(pc_range.clone())
.filter_map(move |(&pc, &insn)| {
if pc_range.end >= pc + insn.byte_len() {
Some((pc, insn))
} else {
None
}
})
}
}
struct MockInsnsBuilder {
insns: BTreeMap<u64, MockInsn>,
labels: BTreeMap<u64, (&'static std::panic::Location<'static>, Option<u64>)>,
available_labels: Range<u64>,
next_pc: u64,
}
impl MockInsnsBuilder {
fn new() -> Self {
Self {
insns: BTreeMap::new(),
labels: BTreeMap::new(),
available_labels: Self::LABEL_RANGE,
next_pc: RESET_PC,
}
}
const LABEL_RANGE: Range<u64> = {
let start = u64::from_be_bytes(*b"Label\0\0\0");
start..start + 0xFFFFFFu64
};
#[track_caller]
fn new_label(&mut self) -> u64 {
let Some(label) = self.available_labels.next() else {
panic!("too many labels");
};
self.labels
.insert(label, (std::panic::Location::caller(), None));
label
}
#[track_caller]
fn define_label(&mut self, label: u64) {
let Some((location, address)) = self.labels.get_mut(&label) else {
panic!("invalid label id: {label:#x}");
};
if address.is_some() {
panic!("label already defined. at: {location}");
}
*address = Some(self.next_pc);
*location = std::panic::Location::caller();
}
#[track_caller]
fn advance_to(&mut self, pc: u64) {
assert!(self.next_pc < pc);
self.next_pc = pc;
}
#[track_caller]
fn insn(&mut self, insn: MockInsn) {
self.insns.insert(self.next_pc, insn);
self.next_pc = self.next_pc.wrapping_add(insn.byte_len());
}
#[track_caller]
fn finish(mut self) -> MockInsns {
for insn in self.insns.values_mut() {
for target in insn.targets_mut() {
let label = *target;
if !Self::LABEL_RANGE.contains(&label) {
continue;
}
match self.labels.get(&label) {
Some((_location, Some(address))) => *target = *address,
Some((location, None)) => {
panic!("label not defined. label created at: {location}");
}
None => panic!("invalid label id: {label:#x}"),
}
}
}
MockInsns {
insns: self.insns.intern_sized(),
}
}
#[track_caller]
fn call(&mut self, target: u64) {
self.insn(MockInsn::Call { target });
}
#[track_caller]
fn br_cond(&mut self, target: u64, cond: MockIntCmp, lhs: MockReg, rhs: MockReg) {
self.insn(MockInsn::BrCond {
target,
cond,
lhs,
rhs,
});
}
#[track_caller]
fn br_cond_i(&mut self, target: u64, cond: MockIntCmp, lhs: MockReg, rhs: u64) {
self.insn(MockInsn::BrCondI {
target,
cond,
lhs,
rhs,
});
}
#[track_caller]
fn add_i(&mut self, dest: MockReg, src: MockReg, immediate: u64) {
self.insn(MockInsn::AddI {
dest,
src,
immediate,
});
}
#[track_caller]
fn imm(&mut self, dest: MockReg, immediate: u64) {
self.add_i(dest, MockReg::Zero, immediate);
}
#[track_caller]
fn print_string(&mut self, temp_reg: MockReg, s: &str) {
for b in s.bytes() {
self.imm(temp_reg, b as u64);
self.insn(MockInsn::WriteOutputByte { src: temp_reg });
}
}
}
fn mock_program_expr_parser() -> MockInsns {
let mut b = MockInsnsBuilder::new();
let peek_reg = MockReg::R7;
let expr = b.new_label();
let mul_div = b.new_label();
let unary = b.new_label();
let atom = b.new_label();
let space = b.new_label();
let error = b.new_label();
b.insn(MockInsn::ReadInputByte { dest: peek_reg });
b.call(space);
b.call(expr);
b.br_cond_i(
error,
MockIntCmp::Ne,
peek_reg,
MockInsn::READ_INPUT_REG_EOF,
);
b.print_string(MockReg::R1, "Success\n");
b.imm(MockReg::R1, 0);
b.insn(MockInsn::ExitSysCall);
b.advance_to(0x80);
b.define_label(error);
b.print_string(MockReg::R1, "Error\n");
b.imm(MockReg::R1, 1);
b.insn(MockInsn::ExitSysCall);
let not_add = b.new_label();
let not_sub = b.new_label();
b.advance_to(0x100);
b.define_label(expr);
b.call(mul_div);
b.br_cond_i(not_add, MockIntCmp::Ne, peek_reg, b'+' as u64);
b.insn(MockInsn::ReadInputByte { dest: peek_reg });
b.call(space);
b.insn(MockInsn::Jump { target: expr });
b.define_label(not_add);
b.br_cond_i(not_sub, MockIntCmp::Ne, peek_reg, b'-' as u64);
b.insn(MockInsn::ReadInputByte { dest: peek_reg });
b.call(space);
b.insn(MockInsn::Jump { target: expr });
b.define_label(not_sub);
b.insn(MockInsn::Ret);
let not_mul = b.new_label();
let not_div = b.new_label();
b.advance_to(0x200);
b.define_label(mul_div);
b.call(unary);
b.br_cond_i(not_mul, MockIntCmp::Ne, peek_reg, b'*' as u64);
b.insn(MockInsn::ReadInputByte { dest: peek_reg });
b.call(space);
b.insn(MockInsn::Jump { target: expr });
b.define_label(not_mul);
b.br_cond_i(not_div, MockIntCmp::Ne, peek_reg, b'/' as u64);
b.insn(MockInsn::ReadInputByte { dest: peek_reg });
b.call(space);
b.insn(MockInsn::Jump { target: expr });
b.define_label(not_div);
b.insn(MockInsn::Ret);
let not_neg = b.new_label();
b.advance_to(0x300);
b.define_label(unary);
b.br_cond_i(not_neg, MockIntCmp::Ne, peek_reg, b'-' as u64);
b.insn(MockInsn::ReadInputByte { dest: peek_reg });
b.call(space);
b.insn(MockInsn::Jump { target: unary });
b.define_label(not_neg);
b.call(atom);
b.insn(MockInsn::Ret);
let not_num = b.new_label();
b.advance_to(0x400);
b.define_label(atom);
b.br_cond_i(not_num, MockIntCmp::Ult, peek_reg, b'0' as u64);
b.br_cond_i(not_num, MockIntCmp::Ugt, peek_reg, b'9' as u64);
let parse_num = b.new_label();
b.define_label(parse_num);
b.insn(MockInsn::ReadInputByte { dest: peek_reg });
b.br_cond_i(space, MockIntCmp::Ult, peek_reg, b'0' as u64);
b.br_cond_i(space, MockIntCmp::Ugt, peek_reg, b'9' as u64);
b.insn(MockInsn::Jump { target: parse_num });
b.define_label(not_num);
b.br_cond_i(error, MockIntCmp::Ne, peek_reg, b'(' as u64);
b.insn(MockInsn::ReadInputByte { dest: peek_reg });
b.call(space);
b.call(expr);
b.br_cond_i(error, MockIntCmp::Ne, peek_reg, b')' as u64);
b.insn(MockInsn::ReadInputByte { dest: peek_reg });
b.insn(MockInsn::Jump { target: space });
let found_space = b.new_label();
b.advance_to(0x500);
b.define_label(space);
b.br_cond_i(found_space, MockIntCmp::Eq, peek_reg, b' ' as u64);
b.br_cond_i(found_space, MockIntCmp::Eq, peek_reg, b'\t' as u64);
b.br_cond_i(found_space, MockIntCmp::Eq, peek_reg, b'\r' as u64);
b.br_cond_i(found_space, MockIntCmp::Eq, peek_reg, b'\n' as u64);
b.insn(MockInsn::Ret);
b.define_label(found_space);
b.insn(MockInsn::ReadInputByte { dest: peek_reg });
b.insn(MockInsn::Jump { target: space });
b.finish()
}
#[test]
fn test_program_expr_parser() {
#[track_caller]
fn test(expected_output: &str, expected_exit_code: u64, input: &str) {
println!("starting new test case: input={input:?}\n\n");
let mut state = MockMachineState::new(mock_program_expr_parser(), input, false);
let exit_code = state.run_until_exit(10000, true).unwrap();
println!("output: {:?}", str::from_utf8(&state.output));
println!("exit code: {exit_code}");
assert!(expected_output.as_bytes() == state.output);
assert_eq!(expected_exit_code, exit_code);
}
test("Success\n", 0, "123 + 456 * 789");
test("Success\n", 0, "123");
test("Success\n", 0, "(123 + 456) * 8 - 9");
test("Success\n", 0, "-5");
test("Success\n", 0, "3");
test("Success\n", 0, TEST_NEXT_PC_INPUT);
test("Error\n", 1, "3-");
test("Error\n", 1, "(123 + 456) + ");
test("Error\n", 1, "(123 + 456");
test("Error\n", 1, "123 ** 456");
}
const FETCH_PIPE_QUEUE_SIZE: usize = 5;
const DEMO_ILLEGAL_INSN_TRAP: u64 = 0xFF000000u64;
#[hdl]
struct FetchPipeQueueEntry {
start_pc: UInt<64>,
cycles_left: UInt<8>,
fetch_block_id: UInt<{ FETCH_BLOCK_ID_WIDTH }>,
}
impl FetchPipeQueueEntry {
#[hdl]
fn default_sim(self) -> SimValue<Self> {
#[hdl(sim)]
FetchPipeQueueEntry {
start_pc: 0u64,
cycles_left: 0u8,
fetch_block_id: 0u8,
}
}
fn get_next_delay(delay_sequence_index: &Cell<u64>) -> u8 {
let index = delay_sequence_index.get();
delay_sequence_index.set(delay_sequence_index.get().wrapping_add(1));
// make a pseudo-random number deterministically based on index
let random = index
.wrapping_add(1)
.wrapping_mul(0x18C49126EABE7A0D) // random prime
.rotate_left(32)
.wrapping_mul(0x92B38C197608A6B) // random prime
.rotate_right(60);
if random % 32 == 0 { 30 } else { 3 }
}
}
#[hdl_module(extern)]
fn mock_fetch_pipe(config: PhantomConst<CpuConfig>, insns: MockInsns) {
#[hdl]
let cd: ClockDomain = m.input();
#[hdl]
let from_fetch: NextPcToFetchInterface<PhantomConst<CpuConfig>> =
m.input(NextPcToFetchInterface[config]);
#[hdl]
let to_post_decode: DecodeToPostDecodeInterface<PhantomConst<CpuConfig>> =
m.output(DecodeToPostDecodeInterface[config]);
#[hdl]
let queue_debug: ArrayVec<FetchPipeQueueEntry, ConstUsize<{ FETCH_PIPE_QUEUE_SIZE }>> =
m.output();
m.register_clock_for_past(cd.clk);
m.extern_module_simulation_fn(
(cd, from_fetch, to_post_decode, queue_debug, insns),
|(cd, from_fetch, to_post_decode, queue_debug, insns), mut sim| async move {
// intentionally have a different sequence each time we're reset
let delay_sequence_index = Cell::new(0);
sim.resettable(
cd,
async |mut sim| {
sim.write(from_fetch.fetch.ready, false).await;
sim.write(from_fetch.cancel.ready, false).await;
sim.write(
from_fetch.next_fetch_block_ids,
#[hdl(sim)]
(from_fetch.next_fetch_block_ids.ty()).HdlNone(),
)
.await;
sim.write(
to_post_decode.inner.data,
to_post_decode.ty().inner.data.HdlNone(),
)
.await;
sim.write(
queue_debug,
queue_debug.ty().new_sim(FetchPipeQueueEntry.default_sim()),
)
.await;
},
|sim, ()| {
run_fn(
cd,
from_fetch,
to_post_decode,
queue_debug,
&delay_sequence_index,
insns,
sim,
)
},
)
.await;
},
);
#[hdl]
async fn run_fn(
cd: Expr<ClockDomain>,
from_fetch: Expr<NextPcToFetchInterface<PhantomConst<CpuConfig>>>,
to_post_decode: Expr<DecodeToPostDecodeInterface<PhantomConst<CpuConfig>>>,
queue_debug: Expr<ArrayVec<FetchPipeQueueEntry, ConstUsize<{ FETCH_PIPE_QUEUE_SIZE }>>>,
delay_sequence_index: &Cell<u64>,
mock_insns: MockInsns,
mut sim: ExternModuleSimulationState,
) {
let config = from_fetch.config.ty();
let mut queue: VecDeque<SimValue<FetchPipeQueueEntry>> = VecDeque::new();
let mut next_id = 0u32;
loop {
let mut sim_queue = queue_debug.ty().new_sim(FetchPipeQueueEntry.default_sim());
let mut next_fetch_block_ids =
from_fetch.next_fetch_block_ids.ty().HdlSome.new_sim(0u8);
for entry in &queue {
ArrayVec::try_push_sim(&mut sim_queue, entry)
.ok()
.expect("queue is known to be small enough");
let _ = ArrayVec::try_push_sim(&mut next_fetch_block_ids, &entry.fetch_block_id);
}
sim.write(queue_debug, sim_queue).await;
sim.write(
from_fetch.next_fetch_block_ids,
#[hdl(sim)]
(from_fetch.next_fetch_block_ids.ty()).HdlSome(next_fetch_block_ids),
)
.await;
if let Some(front) = queue.front().filter(|v| v.cycles_left.as_int() == 0) {
#[hdl(sim)]
let FetchPipeQueueEntry {
start_pc,
cycles_left: _,
fetch_block_id,
} = front;
let start_pc = start_pc.as_int();
let end_pc =
(start_pc + 1).next_multiple_of(config.get().fetch_width_in_bytes() as u64);
let insns = to_post_decode.ty().inner.data.HdlSome.insns;
let zeroed_insn = UInt[insns.element().canonical().bit_width()]
.zero()
.cast_bits_to(insns.element());
let mut insns = insns.new_sim(zeroed_insn);
let mut expected_pc = start_pc;
// TODO: handle instructions that go past the end of a fetch block
for (pc, insn) in mock_insns.fetch_block(start_pc..end_pc) {
let next_pc = pc + insn.byte_len();
if pc != expected_pc {
break;
}
expected_pc = next_pc;
let insn = #[hdl(sim)]
WipDecodedInsn {
fetch_block_id,
id: next_id.cast_to_static::<UInt<_>>(),
pc,
predicted_next_pc: 0u64,
size_in_bytes: insn.byte_len().cast_to_static::<UInt<_>>(),
kind: insn.wip_decoded_insn_kind(),
};
match ArrayVec::try_push_sim(&mut insns, insn) {
Ok(()) => next_id = next_id.wrapping_add(1),
Err(_) => break,
}
}
if **ArrayVec::len_sim(&insns) == 0 {
let Ok(()) = ArrayVec::try_push_sim(
&mut insns,
#[hdl(sim)]
WipDecodedInsn {
fetch_block_id,
id: next_id.cast_to_static::<UInt<_>>(),
pc: start_pc,
predicted_next_pc: 0u64,
size_in_bytes: 0u8.cast_to_static::<UInt<_>>(),
kind: WipDecodedInsnKind.Interrupt(DEMO_ILLEGAL_INSN_TRAP),
},
) else {
unreachable!();
};
next_id = next_id.wrapping_add(1);
}
sim.write(
to_post_decode.inner.data,
HdlSome(
#[hdl(sim)]
DecodeToPostDecodeInterfaceInner::<_> { insns, config },
),
)
.await;
} else {
sim.write(
to_post_decode.inner.data,
to_post_decode.ty().inner.data.HdlNone(),
)
.await;
}
sim.write(from_fetch.fetch.ready, queue.len() < FETCH_PIPE_QUEUE_SIZE)
.await;
sim.write(from_fetch.cancel.ready, true).await;
sim.wait_for_clock_edge(cd.clk).await;
println!(
"Dump mock fetch decode pipe queue: {:#?}",
Vec::from_iter(queue.iter().map(|v| {
DebugAsDisplay(format!(
"fid={:#x} pc={:#x}",
v.fetch_block_id.as_int(),
v.start_pc.as_int(),
))
}))
);
if sim.read_past_bool(to_post_decode.inner.ready, cd.clk).await {
#[hdl(sim)]
if let HdlSome(_) = sim.read_past(to_post_decode.inner.data, cd.clk).await {
let Some(v) = queue.pop_front() else {
unreachable!();
};
println!(
"mock fetch decode pipe queue pop: fid={:#x} pc={:#x}",
v.fetch_block_id.as_int(),
v.start_pc.as_int(),
);
}
}
for entry in &mut queue {
if entry.cycles_left.as_int() > 0 {
entry.cycles_left = (entry.cycles_left.as_int() - 1u8).to_sim_value();
}
}
// handle cancels before pushing new fetch op
#[hdl(sim)]
if let HdlSome(in_progress_fetches_to_cancel) =
sim.read_past(from_fetch.cancel.data, cd.clk).await
{
// cancel in-progress fetches from newest to oldest
for _ in 0..*in_progress_fetches_to_cancel {
let Some(v) = queue.pop_back() else {
unreachable!();
};
println!(
"mock fetch decode pipe queue cancel unpush: fid={:#x} pc={:#x}",
v.fetch_block_id.as_int(),
v.start_pc.as_int(),
);
}
}
if !sim.read_past_bool(from_fetch.fetch.ready, cd.clk).await {
continue;
}
// handle pushing new fetch op after handling cancels
#[hdl(sim)]
if let HdlSome(inner) = sim.read_past(from_fetch.fetch.data, cd.clk).await {
#[hdl(sim)]
let NextPcToFetchInterfaceInner {
start_pc,
fetch_block_id,
} = &inner;
println!(
"mock fetch decode pipe queue push: fid={:#x} pc={:#x}",
fetch_block_id.as_int(),
start_pc.as_int(),
);
queue.push_back(
#[hdl(sim)]
FetchPipeQueueEntry {
start_pc,
cycles_left: FetchPipeQueueEntry::get_next_delay(delay_sequence_index),
fetch_block_id,
},
);
}
}
}
}
const EXECUTE_RETIRE_PIPE_QUEUE_SIZE: usize = 15;
#[hdl]
struct ExecuteRetirePipeQueueEntry {
insn: WipDecodedInsn,
cycles_left: UInt<8>,
}
impl ExecuteRetirePipeQueueEntry {
#[hdl]
fn default_sim(self) -> SimValue<Self> {
#[hdl(sim)]
Self {
insn: #[hdl(sim)]
WipDecodedInsn {
fetch_block_id: 0u8,
id: 0_hdl_u12,
pc: 0u64,
predicted_next_pc: 0u64,
size_in_bytes: 0_hdl_u4,
kind: WipDecodedInsnKind.NonBranch(),
},
cycles_left: 0u8,
}
}
fn get_next_delay(delay_sequence_index: &Cell<u64>) -> u8 {
let index = delay_sequence_index.get();
delay_sequence_index.set(delay_sequence_index.get().wrapping_add(1));
// make a pseudo-random number deterministically based on index
let random = index
.wrapping_add(1)
.wrapping_mul(0x39FF446D8BFB75BB) // random prime
.rotate_left(32)
.wrapping_mul(0x73161B54984B1C21) // random prime
.rotate_right(60);
const DELAYS: &[u8; 0x20] = &[
0, 0, 0, 0, 0, 0, 0, 0, //
1, 1, 1, 1, 1, 1, 1, 1, //
2, 2, 2, 2, 2, 2, 2, 2, //
3, 3, 3, 3, 4, 5, 6, 50, // 50 for simulating a cache miss or something
];
DELAYS[(random & 0x1F) as usize]
}
}
#[derive(Clone)]
struct MockExecuteState {
queue: VecDeque<SimValue<ExecuteRetirePipeQueueEntry>>,
used_ids: BTreeSet<SimValue<UInt<12>>>,
retire_seq: RetireSeq,
canceling: bool,
config: PhantomConst<CpuConfig>,
}
impl MockExecuteState {
fn new(config: PhantomConst<CpuConfig>, retire_seq: RetireSeq) -> Self {
Self {
queue: VecDeque::new(),
used_ids: BTreeSet::new(),
retire_seq,
canceling: false,
config,
}
}
fn on_clock_cycle(&mut self) {
for entry in &mut self.queue {
if entry.cycles_left.as_int() > 0 {
entry.cycles_left = (entry.cycles_left.as_int() - 1u8).to_sim_value();
}
}
}
#[hdl]
fn do_retire(
&mut self,
entry: SimValue<ExecuteRetirePipeQueueEntry>,
passive: bool,
) -> Result<SimValue<RetireToNextPcInterfacePerInsn<PhantomConst<CpuConfig>>>, String> {
#[hdl(sim)]
let ExecuteRetirePipeQueueEntry {
insn,
cycles_left: _,
} = entry;
self.used_ids.remove(&insn.id);
let RetireSeqEntry {
pc,
cond_br_taken,
insn: mock_insn,
} = self
.retire_seq
.next()
.ok_or_else(|| "expected no more instructions to retire")?;
let next_pc = self.retire_seq.0.pc;
let expected_insn = #[hdl(sim)]
WipDecodedInsn {
fetch_block_id: &insn.fetch_block_id,
id: &insn.id,
pc,
predicted_next_pc: &insn.predicted_next_pc,
size_in_bytes: mock_insn.byte_len().cast_to_static::<UInt<4>>(),
kind: mock_insn.wip_decoded_insn_kind(),
};
if *expected_insn.cmp_ne(&insn) {
return Err(format!(
"insn doesn't match expected:\ninsn: {insn:?}\nexpected insn: {expected_insn:?}"
));
}
if next_pc != insn.predicted_next_pc.as_int() {
self.canceling = true;
if !passive {
println!(
"MockExecuteState: starting canceling {} instruction(s): next_pc={next_pc:#x}, mis-predicted next_pc={}",
self.queue.len(),
insn.predicted_next_pc
);
}
}
Ok(
#[hdl(sim)]
RetireToNextPcInterfacePerInsn::<_> {
id: &insn.id,
next_pc,
call_stack_op: mock_insn.call_stack_op(pc),
cond_br_taken: if let Some(cond_br_taken) = cond_br_taken {
#[hdl(sim)]
HdlSome(cond_br_taken)
} else {
#[hdl(sim)]
HdlNone()
},
config: self.config,
},
)
}
#[hdl]
fn try_retire(
&mut self,
passive: bool,
) -> Option<(
SimValue<RetireToNextPcInterfacePerInsn<PhantomConst<CpuConfig>>>,
Result<(), String>,
)> {
if self.canceling {
return None;
}
if self.queue.front()?.cycles_left.as_int() != 0 {
return None;
}
let entry = self.queue.pop_front()?;
let id = entry.insn.id.clone();
Some(match self.do_retire(entry, passive) {
Ok(v) => (v, Ok(())),
Err(e) => (
#[hdl(sim)]
RetireToNextPcInterfacePerInsn::<_> {
id,
next_pc: u64::from_be_bytes(*b"ErrError"),
call_stack_op: #[hdl(sim)]
CallStackOp::None(),
cond_br_taken: #[hdl(sim)]
HdlNone(),
config: self.config,
},
Err(e),
),
})
}
fn space_available(&self) -> usize {
EXECUTE_RETIRE_PIPE_QUEUE_SIZE.saturating_sub(self.queue.len())
}
#[hdl]
fn start(&mut self, insn: &SimValue<WipDecodedInsn>, delay_sequence_index: &Cell<u64>) {
if !self.used_ids.insert(insn.id.clone()) {
panic!("next_pc gave a duplicate insn id: {insn:?}");
}
println!(
"MockExecutionState::start fid={} id={} pc={}",
insn.fetch_block_id, insn.id, insn.pc
);
self.queue.push_back(
#[hdl(sim)]
ExecuteRetirePipeQueueEntry {
insn,
cycles_left: ExecuteRetirePipeQueueEntry::get_next_delay(delay_sequence_index),
},
);
}
#[hdl]
fn finish_cancel(&mut self) {
println!(
"MockExecuteState: finishing canceling {} instruction(s)",
self.queue.len(),
);
self.queue.clear();
self.used_ids.clear();
self.canceling = false;
}
}
#[hdl_module(extern)]
fn mock_execute_retire_pipe(
config: PhantomConst<CpuConfig>,
mock_insns: MockInsns,
mock_input: Interned<str>,
) {
#[hdl]
let cd: ClockDomain = m.input();
#[hdl]
let from_post_decode: PostDecodeOutputInterface<PhantomConst<CpuConfig>> =
m.input(PostDecodeOutputInterface[config]);
#[hdl]
let retire_output: RetireToNextPcInterface<PhantomConst<CpuConfig>> =
m.output(RetireToNextPcInterface[config]);
#[hdl]
let queue_debug: ArrayVec<
ExecuteRetirePipeQueueEntry,
ConstUsize<{ EXECUTE_RETIRE_PIPE_QUEUE_SIZE }>,
> = m.output();
m.register_clock_for_past(cd.clk);
m.extern_module_simulation_fn(
(
cd,
from_post_decode,
retire_output,
queue_debug,
mock_insns,
mock_input,
),
|args, mut sim| async move {
let (cd, from_post_decode, retire_output, queue_debug, mock_insns, mock_input) = args;
// intentionally have a different sequence each time we're reset
let delay_sequence_index = Cell::new(0);
sim.resettable(
cd,
async |mut sim| {
sim.write(from_post_decode.ready, 0usize).await;
sim.write(from_post_decode.cancel.ready, false).await;
sim.write(
retire_output.inner.data,
retire_output.ty().inner.data.HdlNone(),
)
.await;
sim.write(
retire_output.next_insns,
retire_output.next_insns.ty().HdlNone(),
)
.await;
sim.write(
queue_debug,
queue_debug
.ty()
.new_sim(ExecuteRetirePipeQueueEntry.default_sim()),
)
.await;
},
|sim, ()| {
run_fn(
cd,
from_post_decode,
retire_output,
queue_debug,
&delay_sequence_index,
mock_insns,
mock_input,
sim,
)
},
)
.await;
},
);
#[hdl]
async fn run_fn(
cd: Expr<ClockDomain>,
from_post_decode: Expr<PostDecodeOutputInterface<PhantomConst<CpuConfig>>>,
retire_output: Expr<RetireToNextPcInterface<PhantomConst<CpuConfig>>>,
queue_debug: Expr<
ArrayVec<ExecuteRetirePipeQueueEntry, ConstUsize<{ EXECUTE_RETIRE_PIPE_QUEUE_SIZE }>>,
>,
delay_sequence_index: &Cell<u64>,
mock_insns: MockInsns,
mock_input: Interned<str>,
mut sim: ExternModuleSimulationState,
) {
let config = from_post_decode.config.ty();
let mut state = MockExecuteState::new(
config,
RetireSeq::new(MockMachineState::new(mock_insns, mock_input, true)),
);
let empty_retire_insn = #[hdl(sim)]
RetireToNextPcInterfacePerInsn::<_> {
id: 0_hdl_u12,
next_pc: 0u64,
call_stack_op: #[hdl(sim)]
CallStackOp::None(),
cond_br_taken: #[hdl(sim)]
HdlNone(),
config,
};
let retire_vec_ty = retire_output.inner.data.ty().HdlSome.insns;
loop {
state.on_clock_cycle();
let mut sim_queue = queue_debug
.ty()
.new_sim(ExecuteRetirePipeQueueEntry.default_sim());
let mut next_insns = retire_output.next_insns.ty().HdlSome.new_sim(
#[hdl(sim)]
WipDecodedInsn {
fetch_block_id: 0u8,
id: 0_hdl_u12,
pc: 0u64,
predicted_next_pc: 0u64,
size_in_bytes: 0_hdl_u4,
kind: WipDecodedInsnKind.NonBranch(),
},
);
for entry in &state.queue {
ArrayVec::try_push_sim(&mut sim_queue, entry)
.ok()
.expect("queue is known to be small enough");
let _ = ArrayVec::try_push_sim(&mut next_insns, &entry.insn);
}
sim.write(queue_debug, sim_queue).await;
sim.write(
retire_output.next_insns,
if state.canceling {
#[hdl(sim)]
(retire_output.next_insns.ty()).HdlNone()
} else {
#[hdl(sim)]
(retire_output.next_insns.ty()).HdlSome(next_insns)
},
)
.await;
let mut retiring = retire_vec_ty.new_sim(&empty_retire_insn);
let mut peek_state = state.clone();
while let Some((peek_retire, result)) = peek_state.try_retire(true) {
if result.is_err() && **ArrayVec::len_sim(&retiring) > 0 {
break;
}
let Ok(_) = ArrayVec::try_push_sim(&mut retiring, peek_retire) else {
break;
};
}
sim.write(
retire_output.inner.data,
if **ArrayVec::len_sim(&retiring) > 0 {
#[hdl(sim)]
(retire_output.inner.data.ty()).HdlSome(
#[hdl(sim)]
RetireToNextPcInterfaceInner::<_> {
insns: retiring,
config,
},
)
} else {
#[hdl(sim)]
(retire_output.inner.data.ty()).HdlNone()
},
)
.await;
sim.write(
from_post_decode.ready,
if state.canceling {
0
} else {
state.space_available().min(config.get().fetch_width.get())
},
)
.await;
sim.write(from_post_decode.cancel.ready, state.canceling)
.await;
sim.wait_for_clock_edge(cd.clk).await;
println!(
"Dump mock execute retire pipe queue: {:#?}",
Vec::from_iter(state.queue.iter().map(|v| {
DebugAsDisplay(format!(
"fid={:#x} id={} pc={:#x}",
v.insn.fetch_block_id.as_int(),
v.insn.id,
v.insn.pc.as_int(),
))
}))
);
#[hdl(sim)]
if let HdlSome(v) = sim.read_past(from_post_decode.cancel.data, cd.clk).await {
#[hdl(sim)]
let () = v;
if sim
.read_past_bool(from_post_decode.cancel.ready, cd.clk)
.await
{
assert!(state.canceling);
state.finish_cancel();
}
}
if sim.read_past_bool(retire_output.inner.ready, cd.clk).await {
for _ in 0..**ArrayVec::len_sim(&retiring) {
match state.try_retire(false) {
Some((_, Ok(_))) => {}
Some((_, Err(e))) => panic!("retire error: {e}"),
None => unreachable!(),
}
}
}
let mut new_insns = sim.read_past(from_post_decode.insns, cd.clk).await;
ArrayVec::truncate_sim(
&mut new_insns,
*sim.read_past(from_post_decode.ready, cd.clk).await,
);
for insn in ArrayVec::elements_sim_ref(&new_insns) {
state.start(insn, delay_sequence_index);
}
}
}
}
#[hdl_module]
fn dut(config: PhantomConst<CpuConfig>, mock_insns: MockInsns, mock_input: Interned<str>) {
#[hdl]
let cd: ClockDomain = m.input();
#[hdl]
let next_pc = instance(next_pc(config));
#[hdl]
let next_pc {
cd: next_pc_cd,
to_fetch: next_pc_to_fetch,
from_decode: next_pc_from_decode,
post_decode_output: next_pc_post_decode_output,
from_retire: next_pc_from_retire,
state_for_debug: _,
} = next_pc;
connect(next_pc_cd, cd);
#[hdl]
let mock_fetch_pipe = instance(mock_fetch_pipe(config, mock_insns));
#[hdl]
let mock_fetch_pipe {
cd: mock_fetch_pipe_cd,
from_fetch: mock_fetch_pipe_from_fetch,
to_post_decode: mock_fetch_pipe_to_post_decode,
queue_debug: _,
} = mock_fetch_pipe;
connect(mock_fetch_pipe_cd, cd);
connect(mock_fetch_pipe_from_fetch, next_pc_to_fetch);
connect(next_pc_from_decode, mock_fetch_pipe_to_post_decode);
#[hdl]
let mock_execute_retire_pipe =
instance(mock_execute_retire_pipe(config, mock_insns, mock_input));
#[hdl]
let mock_execute_retire_pipe {
cd: mock_execute_retire_pipe_cd,
from_post_decode: mock_execute_retire_pipe_from_post_decode,
retire_output: mock_execute_retire_pipe_retire_output,
queue_debug: _,
} = mock_execute_retire_pipe;
connect(mock_execute_retire_pipe_cd, cd);
connect(next_pc_from_retire, mock_execute_retire_pipe_retire_output);
connect(
mock_execute_retire_pipe_from_post_decode,
next_pc_post_decode_output,
);
}
const TEST_NEXT_PC_INPUT: &str = "(123 + -(456 + 3)) * 7 / 5 + 3";
#[hdl]
#[test]
fn test_next_pc() {
let _n = SourceLocation::normalize_files_for_tests();
let mut config = CpuConfig::new(
vec![
UnitConfig::new(UnitKind::AluBranch),
UnitConfig::new(UnitKind::AluBranch),
],
NonZeroUsize::new(20).unwrap(),
);
config.fetch_width = NonZeroUsize::new(2).unwrap();
let m = dut(
PhantomConst::new_sized(config),
mock_program_expr_parser(),
TEST_NEXT_PC_INPUT.intern(),
);
let mut sim = Simulation::new(m);
let writer = RcWriter::default();
sim.add_trace_writer(VcdWriterDecls::new(writer.clone()));
struct DumpVcdOnDrop {
writer: Option<RcWriter>,
}
impl Drop for DumpVcdOnDrop {
fn drop(&mut self) {
if let Some(mut writer) = self.writer.take() {
let vcd = String::from_utf8(writer.take()).unwrap();
println!("####### VCD:\n{vcd}\n#######");
}
}
}
let mut writer = DumpVcdOnDrop {
writer: Some(writer),
};
sim.write_clock(sim.io().cd.clk, false);
sim.write_reset(sim.io().cd.rst, true);
for cycle in 0..2000 {
sim.advance_time(SimDuration::from_nanos(500));
println!("clock tick: {cycle}");
sim.write_clock(sim.io().cd.clk, true);
sim.advance_time(SimDuration::from_nanos(500));
sim.write_clock(sim.io().cd.clk, false);
sim.write_reset(sim.io().cd.rst, false);
}
// FIXME: vcd is just whatever next_pc does now, which isn't known to be correct
let vcd = String::from_utf8(writer.writer.take().unwrap().take()).unwrap();
println!("####### VCD:\n{vcd}\n#######");
if vcd != include_str!("expected/next_pc.vcd") {
panic!();
}
}