notebook/notes/x86-64/instructions/procedures.md

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title TARGET DECK FILE TAGS tags
Procedures Obsidian::STEM x86-64
x86-64

Overview

The details of procedures are detailed in x86-64/procedures. This file touches on the most relevant instruction classes.

CALL and RET

Like conditions#JMP instructions, call allows specifying a direct or indirect operand. call pushes the address of the instruction following it onto the stack and updates the PC to the operand. ret reverts these steps.

Instruction Operands Description
call Label Procedure call
call *Operand Procedure call
ret Return from call

%%ANKI Cloze The {call} instruction is the counterpart to the {ret} instruction. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.

END%%

%%ANKI Basic What two things does the call instruction do? Back: It pushes the return address on the stack and updates the PC. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.

END%%

%%ANKI Basic What two things does the ret instruction do? Back: It pops the return address off the stack and updates the PC. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.

END%%

%%ANKI Basic How is ret equivalently written using a line of assembly? Back:

popq %rip

Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.

END%%

%%ANKI Basic The operand forms of call mirror what other instruction class? Back: JMP Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.

END%%

%%ANKI Basic A call instruction pushes what address onto the stack? Back: That of the instruction following the call instruction. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.

END%%

%%ANKI Basic What return address is pushed onto the stack after call is run?

1: ...
2: callq .L1
3: ...

Back: 3 Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.

END%%

%%ANKI Basic What address is the PC updated to after call is run?

1: ...
2: callq .L1
3: ...

Back: That corresponding to label .L1. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.

END%%

%%ANKI Basic Which register(s) does a call instruction update? Back: %rsp and %rip. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.

END%%

%%ANKI Basic Which register(s) does a ret instruction update? Back: %rsp and %rip. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.

END%%

LEAVE

leave parallels the ret instruction. It is equivalent to the following two instructions:

movq %rbp, %rsp
popq %rbp

%%ANKI Basic What two things does the leave instruction do? Back: Restores the stack pointer and pops off the caller-saved base pointer. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.

END%%

%%ANKI Basic How is leave equivalently written using a pair of instructions? Back:

movq %rbp, %rsp
popq %rbp

Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.

END%%

%%ANKI Basic Fixed-sized frames use which of leave and/or ret? Back: Just ret. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.

END%%

%%ANKI Basic Variable-sized frames use which of leave and/or ret? Back: Both. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.

END%%

%%ANKI Cloze {1:ret} is to {2:%rsp} whereas {2:leave} is to {1:%rbp}. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.

END%%

Bibliography

  • Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.