Calling Assembly from C++

Notes

• For the test driver for our recient assignment.
• In the assembly file
  • Declare any functions as global
    • global My_isupper
  • Implement the function following the calling conventions

    • My_isupper:
      
           mov rax, rdi
           cmp al, 41h
           jl not
      
           cmp al, 5ah
           jg not
      
           mov rax, 1
           jmp return
      
      not:
           mov rax, 0
      
      return:
           ret

• In the c++ file
  • Declare the function as extern "C"

  • extern "C" {
       int My_isupper(int c);
    }

• see these files