Add a Basic JIT to Your VM

Demonstrate template JIT compilation for your VM in C.

Requirements:

• Use mmap to allocate a read-write-execute memory region
• Implement emit_byte() and emit_bytes() to write x86-64 machine code into the JIT buffer
• Implement emit_mov_rax_imm64() to emit 'mov rax, immediate' (48 B8 + 8 bytes)
• Implement emit_add_rax_rbx() to emit 'add rax, rbx' (48 01 D8)
• Implement emit_sub_rax_rbx() to emit 'sub rax, rbx' (48 29 D8)
• Implement emit_ret() to emit 'ret' (C3)
• Write a JIT compiler that translates a bytecode program into native code:
  • PUSH val -> mov rax, val
  • ADD -> mov rbx, [stack_top]; add rax, rbx
  • SUB -> mov rbx, [stack_top]; sub rax, rbx
  • PRINT -> (placeholder, print rax conceptually)
  • HALT -> ret
• Cast the JIT buffer to a function pointer and call it
• Print the generated machine code bytes in hexadecimal
• Show the JIT-compiled function executing and returning a result

Test:

• Show JIT in output
• Show mmap used for allocation
• Show emitted machine code bytes
• Show native code execution concept