88 lines
3.4 KiB
Markdown
88 lines
3.4 KiB
Markdown
---
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title: Registers
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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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An x86-64 CPU contains a set of 16 general-purpose registers storing 64-bit values. They are used to store integers and pointers.
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1 Byte | 2 Bytes | 4 Bytes | 8 Bytes | Purpose
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------- | ------- | ------- | ------- | -------
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`%al` | `%ax` | `%eax` | `%rax` | Return value
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`%bl` | `%bx` | `%ebx` | `%rbx` | Callee saved
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`%cl` | `%cx` | `%ecx` | `%rcx` | 4th argument
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`%dl` | `%dx` | `%edx` | `%rdx` | 3rd argument
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`%sil` | `%si` | `%esi` | `%rsi` | 2nd argument
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`%dil` | `%di` | `%edi` | `%rdi` | 1st argument
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`%bpl` | `%bp` | `%ebp` | `%rbp` | Callee saved
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`%spl` | `%sp` | `%esp` | `%rsp` | Stack pointer
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`%r8b` | `%r8w` | `%r8d` | `%r8` | 5th argument
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`%r9b` | `%r9w` | `%r9d` | `%r9` | 6th argument
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`%r10b` | `%r10w` | `%r10d` | `%r10` | Caller saved
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`%r11b` | `%r11w` | `%r11d` | `%r11` | Caller saved
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`%r12b` | `%r12w` | `%r12d` | `%r12` | Callee saved
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`%r13b` | `%r13w` | `%r13d` | `%r13` | Callee saved
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`%r14b` | `%r14w` | `%r14d` | `%r14` | Callee saved
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`%r15b` | `%r15w` | `%r15d` | `%r15` | Callee saved
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%%ANKI
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Basic
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How many general-purpose registers are available to x86-64 instructions?
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Back: 16
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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: 1713212889856-->
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END%%
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%%ANKI
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Cloze
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The x86 64-bit registers all start with prefix {`%r`}.
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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: 1713212889861-->
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END%%
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%%ANKI
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Cloze
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The x86 32-bit registers all start with prefix {`%e`}.
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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: 1713212889864-->
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END%%
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%%ANKI
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Basic
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Instructions that generate 1-byte quantities do what to the remaining bytes of a register?
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Back: Leaves them alone.
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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: 1713212889866-->
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END%%
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%%ANKI
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Basic
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Instructions that generate 2-byte quantities do what to the remaining bytes of a register?
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Back: Leaves them alone.
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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: 1713212889869-->
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END%%
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%%ANKI
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Basic
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Instructions that generate 4-byte quantities do what to the remaining bytes of a register?
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Back: Zeroes them out.
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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: 1713212889872-->
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END%%
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%%ANKI
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Basic
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Instructions that generate 8-byte quantities do what to the remaining bytes of a register?
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Back: N/A
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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: 1713212889874-->
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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. |