Call Frames and Machine Code Correlation

For a call to a function, the machine code generated typically does the following:

The machine code before the call performs the following operations:
- Sets some context registers
- Puts the parameters either in registers or memory
- Loads the address of the function into a register
- Loads the address to return to into a register
- Branches to the function
The machine code at the start of the called function performs the following operations:
- Sets some context registers
- Allocates stack space
- Saves some registers in the stack space
- Performs some setup of the local variables
The machine code at the end of the called function performs the following operations:
- Restores the saved registers from the stack space
- Deallocates the stack space
- Branches to the address to return to
The machine code at the return address of the call frame sets some context registers.

When the thread is partway through the call frame creation or tear-down, the debugger will still show the call frame, but will not be able to show correct values for the variables or parameters.