xenia/fox32asm
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fox32asm: Allow labels to be used in sized instructions

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Previously this would cause the CPU to panic with an invalid opcode
error, due to messed up alignment
This commit is contained in:
ry755 2022-02-01 22:00:58 -08:00 committed by Ry
parent 94e02b8f09
commit d0538c59e8
1 changed files with 56 additions and 30 deletions
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78
src/main.rs
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@ -35,19 +35,20 @@ lazy_static! {
#[derive(Debug, Clone)]
struct BackpatchTarget {
index: usize,
size: Size,
is_relative: bool,
instruction: AssembledInstruction,
}
impl BackpatchTarget {
fn new(instruction: &AssembledInstruction, index: usize, is_relative: bool) -> BackpatchTarget {
fn new(instruction: &AssembledInstruction, index: usize, size: Size, is_relative: bool) -> BackpatchTarget {
Self {
index, is_relative,
index, is_relative, size,
instruction: instruction.clone(),
}
}
fn write(&self, address: u32) {
fn write(&self, size: Size, address: u32) {
let ref instruction = self.instruction;
let mut instruction_data = instruction.borrow_mut();
@ -58,16 +59,25 @@ impl BackpatchTarget {
address.to_le_bytes()
};
match size {
Size::Byte => instruction_data[self.index] = address_bytes[0],
Size::Half => {
instruction_data[self.index] = address_bytes[0];
instruction_data[self.index + 1] = address_bytes[1];
},
Size::Word => {
instruction_data[self.index] = address_bytes[0];
instruction_data[self.index + 1] = address_bytes[1];
instruction_data[self.index + 2] = address_bytes[2];
instruction_data[self.index + 3] = address_bytes[3];
}
}
}
}
fn perform_backpatching(targets: &Vec<BackpatchTarget>, address: u32) {
for target in targets {
target.write(address);
target.write(target.size, address);
}
}
@ -232,6 +242,7 @@ enum AstNode {
LabelDefine(String),
LabelOperand {
name: String,
size: Size,
is_relative: bool,
},
LabelOperandPointer {
@ -494,7 +505,7 @@ fn parse_data(pair: pest::iterators::Pair<Rule>) -> AstNode {
Rule::data_word => {
match parse_operand(pair.into_inner().next().unwrap(), false) {
AstNode::Immediate32(word) => AstNode::DataWord(word),
AstNode::LabelOperand {name, is_relative} => AstNode::LabelOperand {name, is_relative},
AstNode::LabelOperand {name, size, is_relative} => AstNode::LabelOperand {name, size, is_relative},
_ => unreachable!(),
}
},
@ -675,6 +686,7 @@ fn parse_operand(mut pair: pest::iterators::Pair<Rule>, is_pointer: bool) -> Ast
} else {
AstNode::LabelOperand {
name: operand_value_pair.as_str().to_string(),
size,
is_relative: false,
}
}
@ -715,8 +727,8 @@ fn parse_instruction_one(pair: pest::iterators::Pair<Rule>, mut operand: AstNode
"loop" => InstructionOne::Loop,
"rjmp" => {
match &mut operand {
&mut AstNode::LabelOperand {name: _, ref mut is_relative} |
&mut AstNode::LabelOperandPointer {name: _, ref mut is_relative} => {
&mut AstNode::LabelOperand {ref mut is_relative, ..} |
&mut AstNode::LabelOperandPointer {ref mut is_relative, ..} => {
*is_relative = true;
}
_ => {}
@ -725,8 +737,8 @@ fn parse_instruction_one(pair: pest::iterators::Pair<Rule>, mut operand: AstNode
},
"rcall" => {
match &mut operand {
&mut AstNode::LabelOperand {name: _, ref mut is_relative} |
&mut AstNode::LabelOperandPointer {name: _, ref mut is_relative} => {
&mut AstNode::LabelOperand {ref mut is_relative, ..} |
&mut AstNode::LabelOperandPointer {ref mut is_relative, ..} => {
*is_relative = true;
}
_ => {}
@ -735,8 +747,8 @@ fn parse_instruction_one(pair: pest::iterators::Pair<Rule>, mut operand: AstNode
},
"rloop" => {
match &mut operand {
&mut AstNode::LabelOperand {name: _, ref mut is_relative} |
&mut AstNode::LabelOperandPointer {name: _, ref mut is_relative} => {
&mut AstNode::LabelOperand {ref mut is_relative, ..} |
&mut AstNode::LabelOperandPointer {ref mut is_relative, ..} => {
*is_relative = true;
}
_ => {}
@ -778,15 +790,15 @@ fn parse_instruction_two(pair: pest::iterators::Pair<Rule>, mut lhs: AstNode, mu
"movz" => InstructionTwo::Movz,
"rta" => {
match &mut lhs {
&mut AstNode::LabelOperand {name: _, ref mut is_relative} |
&mut AstNode::LabelOperandPointer {name: _, ref mut is_relative} => {
&mut AstNode::LabelOperand {ref mut is_relative, ..} |
&mut AstNode::LabelOperandPointer {ref mut is_relative, ..} => {
*is_relative = true;
}
_ => {}
}
match &mut rhs {
&mut AstNode::LabelOperand {name: _, ref mut is_relative} |
&mut AstNode::LabelOperandPointer {name: _, ref mut is_relative} => {
&mut AstNode::LabelOperand {ref mut is_relative, ..} |
&mut AstNode::LabelOperandPointer {ref mut is_relative, ..} => {
*is_relative = true;
}
_ => {}
@ -817,11 +829,11 @@ fn assemble_node(node: AstNode) -> AssembledInstruction {
AstNode::DataStr(string) => {
return string.as_bytes().into();
},
AstNode::LabelOperand {name, is_relative} => {
AstNode::LabelOperand {name, size, is_relative} => {
// label is used on its own, not as an operand:
// LabelOperand was previously only checked as part of operands
let instruction = AssembledInstruction::new();
generate_backpatch_immediate(&name, &instruction, is_relative);
generate_backpatch_immediate(&name, &size, &instruction, is_relative);
return instruction;
},
_ => {}
@ -985,11 +997,16 @@ fn condition_source_destination_to_byte(node: &AstNode) -> u8 {
condition | source | destination
}
fn generate_backpatch_immediate(name: &String, instruction: &AssembledInstruction, is_relative: bool) {
fn generate_backpatch_immediate(name: &String, size: &Size, instruction: &AssembledInstruction, is_relative: bool) {
let index = instruction.borrow().len();
{
let mut vec = instruction.borrow_mut();
for _ in 0..4 {
let range = match size {
Size::Byte => 0..1,
Size::Half => 0..2,
Size::Word => 0..4,
};
for _ in range {
vec.push(0xAB);
}
}
@ -1002,7 +1019,7 @@ fn generate_backpatch_immediate(name: &String, instruction: &AssembledInstructio
table.get_mut(name).unwrap()
}
};
targets.push(BackpatchTarget::new(instruction, index, is_relative));
targets.push(BackpatchTarget::new(instruction, index, *size, is_relative));
}
fn node_to_immediate_values(node: &AstNode, instruction: &AssembledInstruction) {
@ -1022,10 +1039,13 @@ fn node_to_immediate_values(node: &AstNode, instruction: &AssembledInstruction)
AstNode::Immediate32 (immediate) => vec.extend_from_slice(&immediate.to_le_bytes()),
AstNode::ImmediatePointer(immediate) => vec.extend_from_slice(&immediate.to_le_bytes()),
AstNode::LabelOperand {ref name, is_relative} |
AstNode::LabelOperand {ref name, ref size, is_relative} => {
std::mem::drop(vec);
generate_backpatch_immediate(name, size, instruction, is_relative);
}
AstNode::LabelOperandPointer {ref name, is_relative} => {
std::mem::drop(vec);
generate_backpatch_immediate(name, instruction, is_relative);
generate_backpatch_immediate(name, &Size::Word, instruction, is_relative);
}
_ => panic!("Attempting to parse a non-instruction AST node as an instruction: {:#?}", node),
@ -1042,10 +1062,13 @@ fn node_to_immediate_values(node: &AstNode, instruction: &AssembledInstruction)
AstNode::Immediate32 (immediate) => vec.extend_from_slice(&immediate.to_le_bytes()),
AstNode::ImmediatePointer(immediate) => vec.extend_from_slice(&immediate.to_le_bytes()),
AstNode::LabelOperand {ref name, is_relative} |
AstNode::LabelOperand {ref name, ref size, is_relative} => {
std::mem::drop(vec);
generate_backpatch_immediate(name, size, instruction, is_relative);
}
AstNode::LabelOperandPointer {ref name, is_relative} => {
std::mem::drop(vec);
generate_backpatch_immediate(name, instruction, is_relative);
generate_backpatch_immediate(name, &Size::Word, instruction, is_relative);
}
_ => panic!("Attempting to parse a non-instruction AST node as an instruction: {:#?}", node),
@ -1069,10 +1092,13 @@ fn node_to_immediate_values(node: &AstNode, instruction: &AssembledInstruction)
AstNode::ImmediatePointer(immediate) => vec.extend_from_slice(&immediate.to_le_bytes()),
AstNode::LabelOperand {ref name, is_relative} |
AstNode::LabelOperand {ref name, ref size, is_relative} => {
std::mem::drop(vec);
generate_backpatch_immediate(name, size, instruction, is_relative);
}
AstNode::LabelOperandPointer {ref name, is_relative} => {
std::mem::drop(vec);
generate_backpatch_immediate(name, instruction, is_relative);
generate_backpatch_immediate(name, &Size::Word, instruction, is_relative);
}
_ => panic!("Attempting to parse a non-instruction AST node as an instruction: {:#?}", node),