chore: move pointer parsing function to disasm module

src/disasm.rs

@@ -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)),

src/operands.rs

@@ -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::{
+use crate::register::Register;
-    disasm::{DisasmError, Disassembler},
-    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)