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What does Imul do in assembly?
Description. The single-operand form of imul executes a signed multiply of a byte, word, or long by the contents of the AL, AX, or EAX register and stores the product in the AX, DX:AX or EDX:EAX register respectively.
Which is more efficient a mov with an offset or an LEA instruction?
Although using LEA proved that it has an advantage over using offset , it’s more efficient to use offset if the address isn’t very complex to write or both of them will do the same thing with the same number of instructions.
What is Jnz instruction?
The jnz (or jne) instruction is a conditional jump that follows a test. It jumps to the specified location if the Zero Flag (ZF) is cleared (0). jnz is commonly used to explicitly test for something not being equal to zero whereas jne is commonly found after a cmp instruction.
What is the purpose of the Lea instruction?
The lea (load effective address) instruction is used to put a memory address into the destination.
What is the Lea instruction in x86 used for?
The lea (load effective address) instruction is used to put a memory address into the destination. Put [ebx+8] into EAX. After this instruction, EAX will equal 0x00403A48.
What’s the difference between MOV and LEA instructions?
The destination is always a register whereas the source can be an offset address of a variable or a memory location. Both MOV and LEA instructions copy data from source to destination but the difference between them is LEA copies only offset address or a memory address to destination register. The syntax of LEA instruction is:
What’s the purpose of the Lea instruction in Pascal?
As others have pointed out, LEA (load effective address) is often used as a “trick” to do certain computations, but that’s not its primary purpose. The x86 instruction set was designed to support high-level languages like Pascal and C, where arrays—especially arrays of ints or small structs—are common.