---

exercises/asmprogram.s

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+        # Metadata for debuggers and other tools
+        .global main
+        .type main, @function
+        .extern printf
+        .extern scanf
+
+        .section .text  # Begins code and data
+# Label that marks beginning of main function
+main:
+        # Function stack setup
+        pushq %rbp
+        movq %rsp, %rbp
+        subq $128, %rsp  # Reserve 128 bytes of stack space
+
+        # Read an integer into -8(%rbp)
+        movq $scan_format, %rdi  # 1st param: "%ld"
+        leaq -8(%rbp), %rsi      # 2nd param: (%rbp - 8)
+        callq scanf
+        # If the input was invalid, jump to end
+        cmpq $1, %rax
+        jne .Lend
+
+        # Read another integer into -16(%rbp)
+        movq $scan_format, %rdi
+        leaq -16(%rbp), %rsi
+        callq scanf
+        # If the input was invalid, jump to end
+        cmpq $1, %rax
+        jne .Lend
+
+
+        # Add the two integers together
+        movq -8(%rbp), %rax      # Load first integer into %rax
+        addq -16(%rbp), %rax     # Add second integer to %rax
+
+        # Call function 'printf("%ld\n", %rsi)'
+        # to print the number in %rsi.
+        movq $print_format, %rdi
+        movq %rax, %rsi
+        callq printf
+
+# Labels starting with ".L" are local to this function,
+# i.e. another function than "main" could have its own ".Lend".
+.Lend:
+        # Return from main with status code 0
+        movq $0, %rax
+        movq %rbp, %rsp
+        popq %rbp
+        ret
+
+# String data that we pass to functions 'scanf' and 'printf'
+scan_format:
+        .asciz "%ld"
+print_format:
+        .asciz "%ld\n"