AZVM

Azurite Virtual Machine, interpreter for Azurite Bytecode.

Usage

Place the bytecode named as "output.byte" in the same folder as the interpreter and run the interpreter (./main).

Detailed Information

The virtual machine is stack based. The operations push and pop values from the stack. The ISA contains a data stack as well as a callstack. The data stack is used to store values and the callstack is used to store the return addresses of function calls.

Instruction Set

Overview

The instructions have a fixed lenght of 16 bytes. | Opcode (4 bytes) | Operand 1 (4 bytes) | Operand 2 (4 bytes) | Modifier (4 bytes) |

Modifiers format

  31                                       4          2          0
 +-----------------------------------------+----------+----------+
 |             unused                      | OP2_Mode | OP1_Mode |
 +-----------------------------------------+----------+----------+

OP1_Mode:

• 0b00: The operand is at the top of the stack, and will be popped.
• 0b01: Operand 1 is a offset to the callstack's base pointer.
• 0b10: Operand 1 is the absolute position of the value.

OP2_Mode:

• 0x00: The operand is at the top of the stack, and will be popped.
• 0x01: Operand 1 is a offset to the callstack's base pointer.
• 0x02: Operand 1 is the absolute position of the value.

Push Order

The operation a + b will be pushed in the following order:

+-----+ Lowest address
|  a  |  |
|  b  |  v
+-----+ Highest address

When performing the operation, the second operand will be popped first.

Instructions

PUSH (0x01)

Push the value of Operand 1 onto the stack.

POP (0x02)

Pop the value from the stack and discard it.