15 KiB
| title | TARGET DECK | FILE TAGS | tags | |
|---|---|---|---|---|
| Arithmetic Operations | Obsidian::STEM | x86-64 |
|
LEAQ
| Instruction | Operands | Effect | Description |
|---|---|---|---|
leaq |
S, D | D <- &S | Load effective address |
leaq is a variant of MOV. The first operand appears to be a memory address, but instead of reading from the designated location, the instruction copies the effective address to the designated location (a register).
%%ANKI
Basic
leaq is considered a variant of what other instruction class?
Back: MOV
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
Why is the leaq instruction named the way it is?
Back: It stands for load effective address.
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
The {leaq} instruction is to x86-64 as the {&} unary operator is to C.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
Tags: c17
END%%
%%ANKI
Basic
Which x86-64 instruction is used to generate pointers?
Back: leaq
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
Why doesn't leaq have any other size variants?
Back: x96-64 addresses are always 64-bit.
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
Suppose %rdx contains x. Use leaq to set %rax to 5x + 7.
Back: leaq 7(%rdx, %rdx, 4), %rax
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
Besides effective memory computations, how else is leaq used?
Back: For certain arithmetic operations.
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
Assume %rdx holds q. What is the value of %rax in the following?
leaq 9(%rdx),%rax
Back: 9 + q
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
Assume %rbx holds p and %rdx holds q. What is the value of %rax in the following?
leaq (%rdx, %rbx),%rax
Back: q + p
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
Assume %rbx holds p. What is the value of %rax in the following?
leaq 2(%rbx, %rbx, 7),%rax
Back: N/A. A scaling factor of 7 is not allowed.
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
Assume %rdx holds q. What is the value of %rax in the following?
leaq 0xE(, %rdx, 4),%rax
Back: 14 + 4q
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
END%%
Unary Operations
| Instruction | Operands | Effect | Description |
|---|---|---|---|
inc[bwlq] |
D | D <- D + 1 | Increment |
dec[bwlq] |
D | D <- D - 1 | Decrement |
%%ANKI
Basic
What four variants do INC instructions take on in x86-64?
Back: incb, incw, incl, incq
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 instruction class corresponds to effect D \leftarrow D + 1?
Back: INC
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 source/destination types are permitted in unary instructions? Back: Registers and memory addresses. 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 do the instructions in the INC instruction class do?
Back: Increments the specified destination by 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
Cloze
The {INC} instruction class is to x86-64 whereas the {++} operator is to C.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
Tags: c17
END%%
%%ANKI
Basic
What do the instructions in the DEC instruction class do?
Back: Decrements the specified destination by 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
Which instruction class corresponds to effect D \leftarrow D - 1?
Back: DEC
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
The {DEC} instruction class is to x86-64 whereas the {--} operator is to C.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
Tags: c17
END%%
Binary Operations
| Instruction | Operands | Effect | Description |
|---|---|---|---|
add[bwlq] |
S, D | D <- D + S | Addition |
sub[bwlq] |
S, D | D <- D - S | Subtraction |
imul[bwlq] |
S, D | D <- D * S | Multiplication |
%%ANKI
Basic
What four variants do ADD instructions take on in x86-64?
Back: addb, addw, addl, addq
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 combination of source and destination types is prohibited in ADD instructions?
Back: A source and destination memory address.
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 instruction class corresponds to effect D \leftarrow D + S?
Back: ADD
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
The {ADD} instruction class is to x86-64 as the {+=} operator is to C.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
Tags: c17
END%%
%%ANKI
Basic
Which instruction class corresponds to effect D \leftarrow D - S?
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
How is decq %rcx equivalently written using the SUB instruction class?
Back:
subq $1, %rcx
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 SUB 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
Cloze
The {SUB} instruction class is to x86-64 as the {-=} operator is to C.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
Tags: c17
END%%
%%ANKI
Basic
Which instruction class corresponds to effect D \leftarrow D * S?
Back: IMUL
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
The {IMUL} instruction class is to x86-64 as the {*=} operator is to C.
Reference: Bryant, Randal E., and David O'Hallaron. Computer Systems: A Programmer's Perspective. Third edition, Global edition. Always Learning. Pearson, 2016.
Tags: c17
END%%
Shift Operations
| Instruction | Operands | Effect | Description |
|---|---|---|---|
sal[bwlq] |
k, D | D <- D << k | Left shift |
shl[bwlq] |
k, D | D <- D << k | Left shift |
sar[bwlq] |
k, D | D <- D >> k | Arithmetic right shift |
shr[bwlq] |
k, D | D <- D >>> k | Logical right shift |
%%ANKI
Basic
What do instructions in the SAL instruction class do?
Back: Performs a left shift.
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 do instructions in the SHL instruction class do?
Back: Performs a left shift.
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 instruction classes are related to left shifts?
Back: SAL and SHL.
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 instruction classes are related to right shifts?
Back: SAR and SHR.
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 do instructions in the SAR instruction class do?
Back: Performs an arithmetic right shift.
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 do instructions in the SHR instruction class do?
Back: Performs a logical right shift.
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 the SAR and SHR instruction classes?
Back: The former is arithmetic whereas the latter is logical.
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 the SAL and SHL instruction classes?
Back: N/A.
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 do shift operations refer to?
Back: %cl
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 many lower-order bits of %cl does e.g. salb look at?
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 can the source of a shift operation be?
Back: An immediate or the %cl register.
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 can the destination of a shift operation be? Back: A register or memory location. 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 many lower-order bits of %cl does e.g. salw look at?
Back: 4
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 many lower-order bits of %cl does e.g. sall look at?
Back: 5
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 many lower-order bits of %cl does e.g. salq look at?
Back: 6
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.