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How does Imul work 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.
What is the difference between MUL and Imul?
mul is used for unsigned multiplication whereas imul is used for signed multiplication. Algorithm for both are same, which is as follows: when operand is a byte: AX = AL * operand.
Where is Imul stored?
The three forms of the IMUL instruction are similar in that the length of the product is calculated to twice the length of the operands. With the one-operand form, the product is stored exactly in the destination.
How many form does the Imul instruction have?
The imul instruction has two basic formats: two-operand (first two syntax listings above) and three-operand (last two syntax listings above). The two-operand form multiplies its two operands together and stores the result in the first operand. The result (i.e. first) operand must be a register.
How does MUL work in assembly?
The mul instruction is used to perform a multiplication. Always multiplies EAX by a value. The result of the multiplication is stored in a 64-bits value accross EDX (most significant 32 bits of the operation) and EAX (least significant 32 bits of the operation).
What is Movsx Assembly?
Description. movsx reads the contents of the register or effective address as a word or byte. movsx then sign-extends the 16- or 32-bit value to the operand-size attribute of the instruction.
When a word operand is multiplied with AX the result is stored in which register?
8086 Singed Multiplication Instruction (IMUL) When the operand is a byte, it is multiplied with AL register and when it is a word, it is multiplied with AX register.
How many operands are required by Imul instruction?
The IMUL instruction takes one, two or three operands. It can be used for byte, word or dword operation.
When a word operand is multiplied with ax the result is stored in which register?
What’s the difference between a mul and an Imul?
Which is the single operand form of Imul?
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.
Where is the intermediate product stored in IMUL?
The intermediate product (twice the size of the first source operand) is truncated and stored in the destination operand (a general-purpose register). When an immediate value is used as an operand, it is sign-extended to the length of the destination operand format.
Which is an example of an Imul fragment?
IMUL Examples The following fragment computes 8-bit signed multiplication (48 × 4): mov al, 48 mov bl, 4 imul bl ; AX = 00C0h (decimal +192), OF = 1 Because AH is not a sign extension of AL, the Overflow flag is set to 1.