• 1. Program Documentation
  • 1.1. Data Types
  • 1.2. CPU and Register Structures
    • 1.2.1. Registers Structure
    • 1.2.2. Explanation of Registers
    • 1.2.3. CPU Structure
  • 1.3. Opcodes Description
    • 1.3.1. Explanation of Parameters
    • 1.3.2. Notes
  • 1.4. Error Enum Documentation
    • 1.4.1. Usage

1. Program Documentation¶

1.1. Data Types¶

In this system, the following typedefs represent different data types, mapped to their respective sizes. These typedefs are aliased to standard C integer types for clarity and convenience.

1.2. CPU and Register Structures¶

This section describes the structure definitions for Registers and CPU, which represent the state of a CPU and its internal registers.

1.2.1. Registers Structure¶

The Registers structure contains the general-purpose registers used by the CPU. Each register is a Word (16-bit) in size.

1.2.2. Explanation of Registers¶

• AX: Used for arithmetic, logic, and data transfer.
• BX: Primarily used for base addressing.
• CX: Often used as a loop counter or shift count.
• DX: Used for I/O operations and large results (e.g., 32-bit).
• SP: Points to the top of the stack, used for stack operations.
• IP: Tracks the address of the next instruction to execute.

1.2.3. CPU Structure¶

The CPU structure holds the state of the CPU, including the registers and the halt flag.

typedef struct {
    Registers registers;  // Holds the general-purpose registers (AX, BX, CX, DX, SP, IP)
    int halt;             // Halt flag (0 = continue, 1 = halt execution)
} CPU;

• registers: A Registers structure containing the CPU's general-purpose registers.
• halt: A flag indicating whether the CPU should stop execution (1 for halt, 0 for continue).

1.3. Opcodes Description¶

This section describes the available opcodes and their corresponding operations.

1.3.1. Explanation of Parameters¶

• Absolute address: the exact instruction position from the beginning of the file.
• Relative position: A position specified relative to the current stack top position.

1.3.2. Notes¶

• JMP and JNZ are control flow instructions used to modify the program's execution path.
• Stack manipulation instructions like ADD, SUB, MUL, DIV, and EQL modify the stack by performing operations on the top two elements and pushing the result back.

1.4. Error Enum Documentation¶

This section describes the error codes that represent various error conditions that can occur during execution.

1.4.1. Usage¶

These error codes are returned while execution of the instructions.