chore: move register into own module

2025-05-13 16:23:47 +09:00
parent 3cb3f8d4b1
commit f7446c14b1
4 changed files with 128 additions and 123 deletions
--- a/src/register.rs
+++ b/src/register.rs
@@ -0,0 +1,122 @@
+use core::fmt;
+
+use crate::instructions::ImmediateOperand;
+
+#[derive(Debug, Clone)]
+#[allow(dead_code)]
+/// Registers of a 8086 processor
+pub enum Register {
+    // 8 bit
+    // low bytes
+    AL,
+    CL,
+    DL,
+    BL,
+    // high bytes
+    AH,
+    CH,
+    DH,
+    BH,
+
+    // 16 bit
+    AX, // accumulator
+    CX, // counter
+    DX, // data
+    BX, // base
+    SP, // stack pointer
+    BP, // base pointer
+    SI, // source index
+    DI, // base index
+}
+
+/// Selector for Register or Segment Register
+pub type RegisterId = u8;
+
+#[allow(dead_code)]
+impl Register {
+    /// Find the register corresponding to the 8086 bytecode ID
+    pub fn by_id(id: ImmediateOperand) -> Self {
+        match id {
+            ImmediateOperand::Byte(b) => match b {
+                0b000 => Self::AL,
+                0b001 => Self::CL,
+                0b010 => Self::DL,
+                0b011 => Self::BL,
+                0b100 => Self::AH,
+                0b101 => Self::CH,
+                0b110 => Self::DH,
+                0b111 => Self::BH,
+                _ => panic!("Invalid 8bit register ID encountered"),
+            },
+            ImmediateOperand::Word(w) => match w {
+                0b000 => Self::AX,
+                0b001 => Self::CX,
+                0b010 => Self::DX,
+                0b011 => Self::BX,
+                0b100 => Self::SP,
+                0b101 => Self::BP,
+                0b110 => Self::SI,
+                0b111 => Self::DI,
+                _ => panic!("Invalid 16bit register ID encountered"),
+            },
+        }
+    }
+}
+
+impl fmt::Display for Register {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            Self::AX => write!(f, "ax"),
+            Self::BX => write!(f, "bx"),
+            Self::CX => write!(f, "cx"),
+            Self::DX => write!(f, "dx"),
+            Self::AH => write!(f, "ah"),
+            Self::AL => write!(f, "al"),
+            Self::BL => write!(f, "bl"),
+            Self::BH => write!(f, "bh"),
+            Self::CH => write!(f, "ch"),
+            Self::CL => write!(f, "cl"),
+            Self::DH => write!(f, "dh"),
+            Self::DL => write!(f, "dl"),
+            Self::DI => write!(f, "di"),
+            Self::SI => write!(f, "si"),
+            Self::BP => write!(f, "bp"),
+            Self::SP => write!(f, "sp"),
+        }
+    }
+}
+
+/// Segment Registers of a 8086 processor
+#[derive(Debug, Clone)]
+#[allow(dead_code)]
+pub enum SegmentRegister {
+    DS,
+    ES,
+    SS,
+    CS,
+}
+
+#[allow(dead_code)]
+impl SegmentRegister {
+    /// Find the SRegister corresponding to the 8086 bytecode ID
+    pub fn by_id(id: u8) -> Self {
+        match id {
+            0x00 => Self::ES,
+            0x01 => Self::CS,
+            0x10 => Self::SS,
+            0x11 => Self::DS,
+            _ => panic!("Invalid segment register ID encountered"),
+        }
+    }
+}
+
+impl fmt::Display for SegmentRegister {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            Self::DS => write!(f, "ds"),
+            Self::ES => write!(f, "es"),
+            Self::SS => write!(f, "ss"),
+            Self::CS => write!(f, "cs"),
+        }
+    }
+}