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5.3.2 Function call mechanism ¶

When executing ‘call <address>’:

1. Save current context: Push ‘(PC + 1, SP)’ onto the call stack
   • ‘PC + 1’: Address of the instruction following CALL
   • ‘SP’: Current stack pointer (preserves caller’s stack)
2. Jump to function: Set ‘PC = <address>’

When executing ‘Ret’:

1. Pop frame: Retrieve ‘(saved_PC, saved_SP)’ from call stack
2. Restore context:
   • Set ‘PC = saved_PC’ (return to caller)
   • Set ‘SP = saved_SP’ (restore stack state)
3. Check termination: If call stack is empty after pop, terminate program