notebook/notes/x86-64/instructions/condition-codes.md

title	TARGET DECK	FILE TAGS	tags
Condition Code Operations	Obsidian::STEM	x86-64	x86-64

Overview

Instruction	Operands	Based On	Description
cmp[bwlq]	S_1, S_2	S_2 - S_1	Compare
test[bwlq]	S_1, S_2	S_1 \mathop{\&} S_2	Test

%%ANKI Basic What four variants do CMP instructions take on in x86-64? Back: cmpb, cmpw, cmpl, cmpq 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 instruction class is CMP "based" on? Back: SUB 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 registers does CMP affect? Back: The condition code registers. 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 distinguishes CMP from SUB? Back: CMP does not update any destinations. 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 does Bryant et al. recommend reading CMP instructions? Back: As subtracting the first operand from the second. 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 instruction class is TEST "based" on? Back: AND 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 distinguishes TEST from AND? Back: TEST does not update any destinations. 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 four variants do TEST instructions take on in x86-64? Back: testb, testw, testl, testq 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:CMP} is to {2:SUB} as {2:TEST} is to {1:AND}. 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 registers does TEST affect? Back: The condition code registers. Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.

END%%

SET

Instruction	Synonym	Effect	Description
sete	setz	D <- ZF	Equal / zero
setne	setnz	D <- ~ZF	Not equal / not zero
sets		D <- SF	Negative
setns		D <- ~SF	Nonnegative

%%ANKI Basic What value does a SET instruction assign to a destination? Back: 0 or 1 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 large is the destination of a SET instruction? Back: A single byte. 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 is q in the cmpq instruction short for? Back: Quad word. 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 is e in the sete instruction short for? Back: Equal. 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 is z in the setz instruction short for? Back: Zero. 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 {sete} is a synonym for {setz}. 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 is ne in the setne instruction short for? Back: Not equal. 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 is nz in the setnz instruction short for? Back: Not zero. 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 {setne} is a synonym for {setnz}. 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 is s in the sets instruction short for? Back: Signed. 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 is ns in the setns instruction short for? Back: Not signed. 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 {set[ez]} is to {ZF} whereas {sets} is to {SF}. 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 condition code(s) does sete refer to? Back: ZF 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 In terms of condition codes, what value does setz put in its specified destination? Back: ZF 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 condition code(s) does setnz refer to? Back: ZF 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 In terms of condition codes, what value does setne put in its specified destination? Back: ~ZF 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 condition code(s) does sets refer to? Back: SF 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 In terms of condition codes, what value does sets put in its specified destination? Back: SF 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 condition code(s) does setns refer to? Back: SF 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 In terms of condition codes, what value does setns put in its specified destination? Back: ~SF 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.