What does CLTQ do in assembly?
What does CLTQ do in assembly?
The cltq instruction is a specialized movs that operates on %rax . This no-operand instruction does sign-extension in-place on %rax ; source bitwidth is l, destination bitwidth is q. cltq # operates on %rax, sign-extend 4-byte src to 8-byte dst, shorthand for movslq êx,%rax.
What does LEA instruction do?
The lea instruction places the address specified by its first operand into the register specified by its second operand. Note, the contents of the memory location are not loaded, only the effective address is computed and placed into the register.
What is the difference between MOV and Movl?
movl is a mov with operand size 32, objdump leaves out the l suffix if the operand size is clear from the operands.
What is RCX used for?
Registers
| Register | Purpose | Saved across calls |
|---|---|---|
| %rcx | used to pass 4th argument to functions | No |
| %rdx | used to pass 3rd argument to functions | No |
| %rsp | stack pointer | Yes |
| %rbp | callee-saved; base pointer | Yes |
What is the difference between MOV AND Lea?
In short, LEA loads a pointer to the item you’re addressing whereas MOV loads the actual value at that address. Where there are just constants involved, MOV (through the assembler’s constant calculations) can sometimes appear to overlap with the simplest cases of usage of LEA .
What is FS register?
The registers FS and GS are segment registers. They have no processor-defined purpose, but instead are given purpose by the OS’s running them. In Windows 64-bit the GS register is used to point to operating system defined structures. FS and GS are commonly used by OS kernels to access thread-specific memory.
What is the meaning of Movl?
movl is a mov with operand size 32, objdump leaves out the l suffix if the operand size is clear from the operands. – fuz. Jun 5, 2018 at 7:44. 3. Your disassembler use an l operand-size suffix only where the size wasn’t implied by a register operand. (
What does RCX mean in assembly?
Name
| Name | Notes | 8-bit char |
|---|---|---|
| rcx | Typical scratch register. Some instructions also use it as a counter. | ch and cl |
| rdx | Scratch register. | dh and dl |
| rbx | Preserved register: don’t use it without saving it! | bh and bl |
| rsp | The stack pointer. Points to the top of the stack (details coming soon!) | spl |
What is form 1040-x?
Form 1040X is used by individual taxpayers to amend prior year tax returns. File Form 1040-X to do the following. About Form 1040-X, Amended U.S. Individual Income Tax Return | Internal Revenue Service
How do I amend Form 1040X?
Also, don’t complete Parts I or II on page 2 of Form 1040X. Enter in Part III the reason why you are filing Form 1040X. Complete a new or corrected return (Form 1040, Form 1040NR, etc.). Across the top of the new or corrected return, write “Amended.” Attach the new or corrected return to the back of Form 1040X.
What is the difference between RCX 1 and RCX 2?
RCX 1.0 brick, from all sides. The 1.5 brick is identical except that there’s no power jack at the bottom.The 2.0 brick is identical except that there’s no power jack at the bottom and it says “RCX 2.0” instead of “RCX 1.0”.
When do I have to file Form 1040X for a refund?
File Form 1040X only after you have filed your original return. Generally, for a credit or refund, you must file Form 1040X within 3 years (including extensions) after the date you filed your original return or within 2 years after the date you paid the tax, whichever is later.