Stack in Memory and Registers

Register review

So far, we have seen and used general-purpose CPU registers:

• x0/w0
• x1/w1
• x2/w2
• x3/w3
• x4/w4
• …
• x30/w30

We also have special purpose registers:

• XZR/WZR (the zero register)
• pc (the instruction pointer)
• sp (the stack pointer)

Application memory simplified

When an executable file is loaded into memory, we observe the following:

• Its header and sections are mapped to memory pages.
• Some data and code are copied unmodified, but some data is initialized and expanded.
• The first stack is also created at this stage.
• A pc register is set to point to the first program instruction, and sp points to the top of the stack.

This simplified process is shown in the figure below: