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chore: move pointer parsing function to disasm module

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This commit is contained in:
Marco Thomas
2025-05-25 20:31:55 +09:00
parent 74e936ab76
commit f9ae0dc6ee
2 changed files with 22 additions and 41 deletions
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27
src/disasm.rs
View File

@@ -2,7 +2,7 @@
use crate::aout::Aout;
use crate::operands::{
Byte, Displacement, IByte, IWord, MemoryIndex, ModRmTarget, Operand, Pointer, Word,
Byte, DWord, Displacement, IByte, IWord, MemoryIndex, ModRmTarget, Operand, Pointer, Word,
};
use crate::register::{Register, RegisterId, SegmentRegister};
use crate::{
@@ -157,6 +157,21 @@ impl Disassembler {
Ok(word + next_addr)
}
/// Parse a pointer type.
pub fn parse_ptr(&mut self) -> Result<Pointer, DisasmError> {
log::debug!("Attempting to parse pointer at {} ...", self.offset);
let byte0 = self.parse_byte()?;
let byte1 = self.parse_byte()?;
let byte2 = self.parse_byte()?;
let byte3 = self.parse_byte()?;
Ok(Pointer {
raw: DWord::from_le_bytes([byte0, byte1, byte2, byte3]),
segment: Word::from_le_bytes([byte0, byte1]),
offset: Word::from_le_bytes([byte2, byte3]),
})
}
/// Takes in a modrm byte and returns mod, reg and r/m.
fn deconstruct_modrm_byte(modrm: u8) -> (u8, u8, u8) {
let mode = (modrm >> 6) & 0b11;
@@ -375,7 +390,7 @@ impl Disassembler {
/// 2 words parsed for a `Pointer` type.
pub fn modrm_mp(&mut self) -> Result<(ModRmTarget, Pointer), DisasmError> {
let (target, _) = self.parse_modrm_byte(Operand::Byte(0))?;
let ptr = Pointer::new(self)?;
let ptr = self.parse_ptr()?;
Ok((target, ptr))
}
@@ -594,7 +609,7 @@ impl Disassembler {
0x98 => Mnemonic::CBW,
0x99 => Mnemonic::CWD,
0x9A => Mnemonic::CALL_p(Pointer::new(self)?),
0x9A => Mnemonic::CALL_p(self.parse_ptr()?),
0x9B => Mnemonic::WAIT,
@@ -714,7 +729,7 @@ impl Disassembler {
0xE8 => Mnemonic::CALL_v(self.parse_j_word()?),
0xE9 => Mnemonic::JMP_v(self.parse_j_word()?),
0xEA => Mnemonic::JMP_p(Pointer::new(self)?),
0xEA => Mnemonic::JMP_p(self.parse_ptr()?),
0xEB => Mnemonic::JMP_b(self.parse_j_byte()?),
0xEC => Mnemonic::IN_ALDX,
@@ -763,9 +778,9 @@ impl Disassembler {
0b000 => Mnemonic::INC_Mod(target),
0b001 => Mnemonic::DEC_Mod(target),
0b010 => Mnemonic::CALL_Mod(target),
0b011 => Mnemonic::CALL_Mp(target, Pointer::new(self)?),
0b011 => Mnemonic::CALL_Mp(target, self.parse_ptr()?),
0b100 => Mnemonic::JMP_Mod(target),
0b101 => Mnemonic::JMP_Mp(target, Pointer::new(self)?),
0b101 => Mnemonic::JMP_Mp(target, self.parse_ptr()?),
0b110 => Mnemonic::PUSH_Mod(target),
// 0b111 => unused
_ => return Err(DisasmError::IllegalGroupMnemonic(5, reg)),

36
src/operands.rs
View File

@@ -1,10 +1,7 @@
//! All types which a Mnemonic can have as some kind of operand.
//! This includes things such as immediates, ModRM byte targets, etc. etc.
use crate::{
disasm::{DisasmError, Disassembler},
register::Register,
};
use crate::register::Register;
use core::fmt;
pub type Byte = u8; // b
@@ -139,37 +136,6 @@ pub struct Pointer {
pub offset: Word,
}
impl Pointer {
pub fn new(disasm: &mut Disassembler) -> Result<Self, DisasmError> {
log::debug!(
"Seeking 4 bytes ahead of current text offset... ({} + 4)",
disasm.offset
);
let byte0 = disasm
.text
.get(disasm.offset)
.ok_or(DisasmError::ReadBeyondTextSection(disasm.clone()))?;
let byte1 = disasm
.text
.get(disasm.offset + 1)
.ok_or(DisasmError::ReadBeyondTextSection(disasm.clone()))?;
let byte2 = disasm
.text
.get(disasm.offset + 2)
.ok_or(DisasmError::ReadBeyondTextSection(disasm.clone()))?;
let byte3 = disasm
.text
.get(disasm.offset + 3)
.ok_or(DisasmError::ReadBeyondTextSection(disasm.clone()))?;
Ok(Pointer {
raw: DWord::from_le_bytes([*byte0, *byte1, *byte2, *byte3]),
segment: disasm.parse_word()?,
offset: disasm.parse_word()?,
})
}
}
impl std::fmt::Display for Pointer {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
write!(f, "[{:#04x}] ({}:{})", self.raw, self.segment, self.offset)