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Tableswitch implementation

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vegowotenks 2024-09-10 23:28:31 +02:00
parent b053461e74
commit d7d159d115
2 changed files with 66 additions and 2 deletions
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36
src/bytecode.rs
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@ -34,6 +34,7 @@ impl Bytecode {
0x13 => (Instruction::LoadCostantWide((self.bytes[offset+1] as u16) << 8 | self.bytes[offset+2] as u16), 3),
0x14 => (Instruction::LoadConstant64((self.bytes[offset+1] as u16) << 8 | self.bytes[offset+2] as u16), 3),
0x15 => (Instruction::LoadLocalInt(self.bytes[offset+1]), 2),
0x19 => (Instruction::LoadLocalReference(self.bytes[offset+1]), 2),
0x1A => (Instruction::LoadLocalInt0(), 1),
0x1B => (Instruction::LoadLocalInt1(), 1),
@ -80,8 +81,10 @@ impl Bytecode {
0x7A => (Instruction::ArithmeticShiftIntRight(), 1),
0x7C => (Instruction::LogicalShiftIntRight(), 1),
0x7E => (Instruction::AndInt(), 1),
0x80 => (Instruction::OrInt(), 1),
0x82 => (Instruction::XorInt(), 1),
0x84 => (Instruction::IncrementLocalInt(self.bytes[offset+1], i8::from_be_bytes([self.bytes[offset+2]])), 3),
0x95 => (Instruction::CompareFloatL(), 1),
@ -148,6 +151,33 @@ impl Bytecode {
(Instruction::BranchAlways(i16::from_be_bytes(bytes)), 3)
}
0xAA => {
let padding = 4 - (offset % 4) - 1;
let default_bytes = [self.bytes[offset+padding+1], self.bytes[offset+padding+2], self.bytes[offset+padding+3], self.bytes[offset+padding+4]];
let default = i32::from_be_bytes(default_bytes);
let low_bytes = [self.bytes[offset+padding+5], self.bytes[offset+padding+6], self.bytes[offset+padding+7], self.bytes[offset+padding+8]];
let low = i32::from_be_bytes(low_bytes);
let high_bytes = [self.bytes[offset+padding+9], self.bytes[offset+padding+10], self.bytes[offset+padding+11], self.bytes[offset+padding+12]];
let high = i32::from_be_bytes(high_bytes);
// TODO: Throw
assert!(low <= high);
let offsets_count = (high - low + 1) as usize;
let mut offsets_vec = Vec::with_capacity(offsets_count);
for i in 0..offsets_count {
let offset_bytes = [self.bytes[offset+padding+12+(i*4)+1], self.bytes[offset+padding+12+(i*4)+2], self.bytes[offset+padding+12+(i*4)+3], self.bytes[offset+padding+12+(i*4)+4]];
let offset = i32::from_be_bytes(offset_bytes);
offsets_vec.push(offset);
}
(Instruction::TableSwitch(default, low, high, offsets_vec.into()), 1 + padding + 12 + 4 * offsets_count)
}
0xAB => {
let padding = 4 - (offset % 4) - 1;
let default_bytes = [self.bytes[offset+padding+1], self.bytes[offset+padding+2], self.bytes[offset+padding+3], self.bytes[offset+padding+4]];
@ -248,6 +278,7 @@ pub enum Instruction {
LoadCostantWide(u16) = 0x13, // Push from constant pool with wide index, don't load
// double or long or whatever
LoadConstant64(u16) = 0x14, // Push Long or Double from constant pool
LoadLocalInt(u8) = 0x15, // Load int from indexed local variable
LoadLocalReference(u8) = 0x19, // Load reference from indexed local variable
LoadLocalInt0() = 0x1A, // Load int from local variable
LoadLocalInt1() = 0x1B, // Load int from local variable
@ -294,8 +325,10 @@ pub enum Instruction {
ArithmeticShiftIntRight() = 0x7A, // shift int
LogicalShiftIntRight() = 0x7C, // shift int right with zero extension
AndInt() = 0x7E, // bitwise and
OrInt() = 0x80, // value, value => or
XorInt() = 0x82, // value, value => xor
IncrementLocalInt(u8, i8) = 0x84, // increment local variable by constant i8
CompareFloatL() = 0x95, // compare float, push -1 if one is NaN
@ -317,7 +350,8 @@ pub enum Instruction {
BranchReferenceInequality(i16) = 0xA6,
BranchAlways(i16) = 0xA7, // branch if true
LookupSwitch(i32, Box<[(i32, i32)]>) = 0xAB, // offset based on switch value
TableSwitch(i32, i32, i32, Box<[i32]>) = 0xAA, // jump based on indexed range
LookupSwitch(i32, Box<[(i32, i32)]>) = 0xAB, // jump based on switch value
ReturnInt() = 0xAC, // return integer from function
ReturnReference() = 0xB0, // return top-ref from current function