The IDIV (signed divide) instruction
performs signed integer division
, using the same operands as the DIV instruction. For both DIV and IDIV, all of the arithmetic status flags are undefined after the operation. When doing 8-bit division, you must sign-extend the dividend into AH before using IDIV.
What does IDIV mean?
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What is Div and IDIV instructions?
The
DIV instruction divides unsigned numbers, and IDIV divides signed numbers
. Both return a quotient and a remainder. Table 4.1 summarizes the division operations. The dividend is the number to be divided, and the divisor is the number to divide by.
Which flag is affected by IDIV operation?
Flags Affected ¶
The CF, OF, SF, ZF, AF, and PF flags are
undefined
.
What does MUL and DIV instructions do?
There are two instructions for multiplying binary data. The
MUL (Multiply) instruction handles unsigned data and the IMUL (Integer Multiply) handles signed data
. Both instructions affect the Carry and Overflow flag.
What is MUL instruction?
Purpose
.
Multiplies the contents of two general-purpose registers
and stores the result in a third general-purpose register. Note: The mul instruction is supported only in the POWER® family architecture. Syntax.
How do you use IDIV?
The IDIV (signed divide) instruction performs signed integer division, using the same operands as the DIV instruction. For both DIV and IDIV, all of the arithmetic status flags are undefined after the operation. When doing 8-bit division, you must sign-
extend
the dividend into AH before using IDIV.
How does CDQ work?
The CDQ instruction
copies the sign (bit 31) of the value in the EAX register into every bit position in the EDX register
. … The CQO instruction can be used to produce a double quadword dividend from a quadword before a quadword division. The CWD and CDQ mnemonics reference the same opcode.
What does IDIV mean in assembly?
Description. idiv executes
signed division
. idiv divides a 16-, 32-, or 64-bit register value (dividend) by a register or memory byte, word, or long (divisor). The size of the divisor (8-, 16- or 32-bit operand) determines the particular register used as the dividend, quotient, and remainder.
What is CLTD Assembly?
Description. cltd
converts the signed long in EAX to a signed double long in EDX
:EAX by extending the most-significant bit (sign bit) of EAX into all bits of EDX.
How does MOV work in assembly?
The mov instruction
copies the data item referred to by its second operand
(i.e. register contents, memory contents, or a constant value) into the location referred to by its first operand (i.e. a register or memory). While register-to-register moves are possible, direct memory-to-memory moves are not.
How do you divide by 2 in assembly?
To divide by two,
you shift the register right one place
. The low bit is shifted into the Carry flag. So if the number is even, 0 is shifted into CF. If the number is odd, 1 is shifted into CF.
What does CQTO do in assembly?
There is a specific instruction for this, cqto (
convert quad to oct
) in AT&T and cqo in Intel syntax. AFAIK newer versions of gas accept both names. The idivq instruction divides a 128-bit integer ( rdx:rax ) by the given source operand. rax holds the lower 64-bits of the dividend.
What are the arithmetic instructions?
The arithmetic instructions
define the set of operations performed by the processor
Arithmetic Logic Unit (ALU). The arithmetic instructions are further classified into binary, decimal, logical, shift/rotate, and bit/byte manipulation instructions.
How does division instruction work?
div divides a 16-, 32-, or 64-bit register value (dividend)
by a register or memory byte, word, or long (divisor)
. The quotient is stored in the AL, AX, or EAX register respectively. The remainder is stored in AH, Dx, or EDX.
What is the use of push in 8086?
PUSH then places the operand on the new top of stack, which is pointed to by the stack pointer. The 80386 PUSH eSP instruction pushes the value of eSP as it existed before the instruction. This differs from the 8086, where PUSH SP
pushes the new
value (decremented by 2).
