98 lines
3.4 KiB
Markdown
98 lines
3.4 KiB
Markdown
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---
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title: Condition Code Operations
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TARGET DECK: Obsidian::STEM
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FILE TAGS: x86-64
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tags:
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- x86-64
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---
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## Overview
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| Instruction | Operands | Based On | Description |
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| ------------ | ---------- | --------------------- | ----------- |
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| `cmp[bwlq]` | $S_1, S_2$ | $S_2 - S_1$ | Compare |
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| `test[bwlq]` | $S_1, S_2$ | $S_1 \mathop{\&} S_2$ | Test |
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%%ANKI
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Basic
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What four variants do `CMP` instructions take on in x86-64?
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Back: `cmpb`, `cmpw`, `cmpl`, `cmpq`
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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<!--ID: 1717941416479-->
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END%%
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%%ANKI
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Basic
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What instruction class is `CMP` "based" on?
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Back: `SUB`
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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<!--ID: 1717941416483-->
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END%%
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%%ANKI
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Basic
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What registers does `CMP` affect?
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Back: The condition code registers.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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<!--ID: 1717941416486-->
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END%%
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%%ANKI
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Basic
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What distinguishes `CMP` from `SUB`?
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Back: `CMP` does not update any destinations.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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<!--ID: 1717941416490-->
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END%%
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%%ANKI
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Basic
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How does Bryant et al. recommend reading `CMP` instructions?
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Back: As subtracting the first operand *from* the second.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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<!--ID: 1717941416493-->
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END%%
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%%ANKI
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Basic
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What instruction class is `TEST` "based" on?
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Back: `AND`
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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<!--ID: 1717941416497-->
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END%%
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%%ANKI
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Basic
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What distinguishes `TEST` from `AND`?
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Back: `TEST` does not update any destinations.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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<!--ID: 1717941416500-->
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END%%
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%%ANKI
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Basic
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What four variants do `TEST` instructions take on in x86-64?
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Back: `testb`, `testw`, `testl`, `testq`
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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<!--ID: 1717941416504-->
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END%%
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%%ANKI
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Cloze
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{1:`CMP`} is to {2:`SUB`} as {2:`TEST`} is to {1:`AND`}.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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<!--ID: 1717941416508-->
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END%%
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%%ANKI
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Basic
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What registers does `TEST` affect?
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Back: The condition code registers.
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Reference: Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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<!--ID: 1717941416513-->
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END%%
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## Bibliography
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* Bryant, Randal E., and David O'Hallaron. *Computer Systems: A Programmer's Perspective*. Third edition, Global edition. Always Learning. Pearson, 2016.
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