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feat: add conditional jumps

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This commit is contained in:
Alain Zscheile 2022-09-24 01:49:44 +02:00
parent b410e7a5b8
commit 6557e172e7
3 changed files with 46 additions and 0 deletions
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1
crates/fogtix-bytecode/src/consts.rs
View file

@ -24,6 +24,7 @@ pub enum OpType {
CallRemote = 0x6372, /* cr */
CallLocal = 0x636c, /* cl */
Jump = 0x6a70, /* jp */
JumpCond = 0x6a63, /* jc */
Return = 0x7274, /* rt */
Push = 0x7073, /* ps */

7
crates/fogtix-bytecode/src/instr.rs
View file

@ -19,6 +19,10 @@ pub enum Instr<'a> {
/// jumps to the destination $0 inside of the current module
Jump(u64),
/// pops the top stack value and if it is non-zero, jumps to the specified destination
/// inside of the current module
JumpCond(u64),
/// pops the current call frame
Return,
@ -50,6 +54,7 @@ impl Instr<'_> {
Instr::CallRemote(_, _) => OpType::CallRemote,
Instr::CallLocal(_) => OpType::CallLocal,
Instr::Jump(_) => OpType::Jump,
Instr::JumpCond(_) => OpType::JumpCond,
Instr::Return => OpType::Return,
Instr::Push(_) => OpType::Push,
Instr::Pop(_) => OpType::Pop,
@ -101,6 +106,7 @@ impl<'a> crate::Parse<'a> for Instr<'a> {
}
OpType::CallLocal => u64::parse(inp).map(|(inp, val)| (inp, Instr::CallLocal(val))),
OpType::Jump => u64::parse(inp).map(|(inp, val)| (inp, Instr::Jump(val))),
OpType::JumpCond => u64::parse(inp).map(|(inp, val)| (inp, Instr::JumpCond(val))),
OpType::Push => Ok(Value::parse(inp).map(|(inp, val)| (inp, Instr::Push(val)))?),
OpType::Pop => u32::parse(inp).map(|(inp, val)| (inp, Instr::Pop(val))),
OpType::OnAtom => AtomOp::parse(inp).map(|(inp, val)| (inp, Instr::OnAtom(val))),
@ -126,6 +132,7 @@ impl Instr<'_> {
}
Instr::CallLocal(val) => writer.write_all(&val.to_be_bytes())?,
Instr::Jump(val) => writer.write_all(&val.to_be_bytes())?,
Instr::JumpCond(val) => writer.write_all(&val.to_be_bytes())?,
Instr::Push(val) => val.write_to(writer)?,
Instr::Pop(val) => writer.write_all(&val.to_be_bytes())?,
Instr::DoMath2(val) => writer.write_all(&val.int_value().to_be_bytes())?,

38
crates/fogtix-vm/src/main.rs
View file

@ -179,6 +179,44 @@ impl Process {
break;
}
}
Instr::JumpCond(x) => {
let x: usize = match x.try_into() {
Ok(y) => y,
Err(_) => {
tracing::error!(
"jump to out-of-bounds address @ {} -> {}",
previptr,
x
);
break;
}
};
let doit = match self.stack.pop() {
None => {
tracing::error!(
"popped empty stack during condition jump eval @ {}",
previptr
);
break;
}
Some(StackEntValue::Int(i)) => i != 0,
Some(StackEntValue::Atom(a)) => a != Atom(0, 0),
Some(z) => {
tracing::error!(
"encountered invalid condition value {:?} @ {}",
z,
previptr
);
break;
}
};
if doit {
self.instrp.1 = x;
if !self.verify_jumptarget(previptr, "jump-cond") {
break;
}
}
}
Instr::Return => match self.callstack.pop() {
Some(x) => self.instrp = x,
None => {