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remove indirection in jmp instructions

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This commit is contained in:
Mark Thom
2018-01-25 09:10:30 -07:00
parent f2124448d0
commit 700f031cd9
6 changed files with 24 additions and 22 deletions
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20
src/prolog/io.rs
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@@ -137,10 +137,10 @@ impl fmt::Display for ControlInstruction {
write!(f, "is_call {}, {}", r, at),
&ControlInstruction::IsExecute(r, ref at) =>
write!(f, "is_execute {}, {}", r, at),
&ControlInstruction::JmpByCall(arity, ref offset) =>
write!(f, "jmp_by_call {}/{}", offset.get(), arity),
&ControlInstruction::JmpByExecute(arity, ref offset) =>
write!(f, "jmp_by_execute {}/{}", offset.get(), arity),
&ControlInstruction::JmpByCall(arity, offset) =>
write!(f, "jmp_by_call {}/{}", offset, arity),
&ControlInstruction::JmpByExecute(arity, offset) =>
write!(f, "jmp_by_execute {}/{}", offset, arity),
&ControlInstruction::Proceed =>
write!(f, "proceed"),
&ControlInstruction::ThrowCall =>
@@ -412,13 +412,15 @@ fn compile_relation(tl: &TopLevel) -> Result<Code, ParserError>
// set first jmp_by_call or jmp_by_index instruction to code.len() - idx,
// where idx is the place it occurs. It only does this to the *first* uninitialized
// jmp index it encounters, then returns.
fn set_first_index(code: &Code)
fn set_first_index(code: &mut Code)
{
for (idx, line) in code.iter().enumerate() {
let code_len = code.len();
for (idx, line) in code.iter_mut().enumerate() {
match line {
&Line::Control(ControlInstruction::JmpByExecute(_, ref offset))
| &Line::Control(ControlInstruction::JmpByCall(_, ref offset)) if offset.get() == 0 => {
offset.set(code.len() - idx);
&mut Line::Control(ControlInstruction::JmpByExecute(_, ref mut offset))
| &mut Line::Control(ControlInstruction::JmpByCall(_, ref mut offset)) if *offset == 0 => {
*offset = code_len - idx;
break;
},
_ => {}