What does Movl mean in assembly code?

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. 2. Your disassembler use an l operand-size suffix only where the size wasn’t implied by a register operand. (

What is Movl x86?

movl %cs:var, êx. Move the contents of memory location var in the code segment (register %cs) into number register êx.

What is sub in x86?

The SUB instruction performs integer subtraction. It evaluates the result for both signed and unsigned integer operands and sets the OF and CF flags to indicate an overflow in the signed or unsigned result, respectively.

What does sub do in assembly?

The SUB instruction subtracts the value of Operand2 or imm12 from the value in Rn . In certain circumstances, the assembler can substitute one instruction for another.

What does Movl do to upper 4 bytes?

movl will write into all 4 bytes. In your example, it’ll zero out the upper 3 bytes, and put 1 in the lowest byte.

What is the difference between MOV and Movl?

movq moves 8 bytes starting at the current specified memory address whereas movl moves 4 bytes starting at the current specificed memory address. FYI, there are two other move suffixes (movb which moves a single byte and movw which moves 2 byte). For each assembly instruction (e.g. mov, xchg, call, etc.)

What is sub microprocessor?

Microprocessor8085. In 8085 Instruction, SUB is a mnemonic that stands for ‘SUBtract contents of R from Accumulator. Here R stands for any of the following registers, or memory location M pointed by HL pair.

What is the difference between sub and CMP instruction?

CMP is used for comparing 2 registers by subtraction them from one another, but answer is not saved, whereas SUB subtracts 2 registers and saves the answer. The main difference between cmp and sub is that cmp does not store the result of the subtract operation; it performs subtraction only to set the status flags.

What is RSB in arm?

Usage. The RSB instruction subtracts the value in Rn from the value of Operand2 . This is useful because of the wide range of options for Operand2 .

What is x86 machine?

X86 is the term used to denote the microprocessor family based on the Intel 8086 and 8088 microprocessors. These microprocessors ensure backward compatibility for instruction set architectures. Initially x86 started with an 8-bit instruction set, but then grew to 16- and 32-bit instruction sets.

What is sub instruction?

SUB Instruction. The SUB instruction performs a subtraction on the first source register’s contents by the second source. register’s contents, and stores the result in the destination register.

What is the x86 assembly guide?

x86 Assembly Guide. This is a version adapted by Quentin Carbonneaux from David Evans’ original document. The syntax was changed from Intel to AT, the standard syntax on UNIX systems, and the HTML code was purified.

Is there a 16-bit subset of x86?

For example, there is a 16-bit subset of the x86 instruction set. Using the 16-bit programming model can be quite complex. It has a segmented memory model, more restrictions on register usage, and so on.

How big is the x86 instruction set?

The full x86 instruction set is large and complex (Intel’s x86 instruction set manuals comprise over 2900 pages), and we do not cover it all in this guide. For example, there is a 16-bit subset of the x86 instruction set.

What are the addressing modes of x86 instructions?

The addressing modes can be used with many x86 instructions (we’ll describe them in the next section). Here we illustrate some examples using the mov instruction that moves data between registers and memory. This instruction has two operands: the first is the source and the second specifies the destination.