Changes

The code examples for this lab are available in the file /public/spo600-assembler-lab-examples.tgz on both [[SPO600 Servers|Betty Aarchie and Xerxes]]

|-- hello2.c # write() version |-- hello3.c # syscall () wrapper version |-- hello.c # printf () version

=== References Resources ===

1. Build and run the two three C versions of the program for x86_64. Take a look at the differences in the code.

2. Use the <code>objdump -d</code> command to dump (print) the object code (machine code) and disassemble it into assembler for each of the two binaries. Find the <code><nowiki><main></nowiki></code> section and take a look at the code. Notice the total amount of code.

3. Review, build, and run the x86_64 assembly language programs. Take a look at the code using <code>objdump -d'''objectfile'''</code> and compare it to the source code. Notice the absence of other code(compared to the C binary, which had a lot of extra code).

4. Build and run the two three C versions of the program for aarch64. Verify that you can disassemble the object code in the ELF binary using <code>objdump -d'''objectfile'''</code> and take a look at the code.

5. Review, build, and run the aarch64 assembly language programs. Take a look at the code using <code>objdump -d'''objectfile'''</code> and compare it to the source code.

start = 0 /* starting value for the loop index; '''note that this is a symbol (constant)''', not a variable */

/* '''... body of the loop ... do something useful here ... ''' */

Extend this This codedoesn't actually do anything while looping, combining because the body of the loop is empty. Combine it with code from the "Hello World" example, so that it prints a word each time it loops:  Loop Loop Loop Loop Loop Loop Loop Loop Loop Loop Then modify the message so that it includes the loop index values, showing each digit from 0 to 9 like this: