Assembler:Commands:DIV

command div operand

Divids the data register (high) and the accumulator register (low) by the operand. Placing the quotient in the accumulator register and the remainder in the data register.

Divides (unsigned) the value in the AH:AL, DX:AX, EDX:EAX, or RDX:RAX registers (dividend) by the source operand (divisor) and stores the result in the AH:AL, DX:AX, EDX:EAX, or RDX:RAX registers.

Results

Dividend	Divisor	Quotient	Remainder	Maximum Quotient
Word/Byte	AX	r/m8	AL	AH	2^8 - 1
Doubleword/Word	DX:AX	r/m16	AX	DX	2^16 - 1
Quadword/Doubleword	EDX:EAX	r/m32	EAX	EDX	2^32 - 1
Octoword/Quadword	RDX:RAX	r/m64	RAX	RDX	2^64 - 1

The source operand can be a general-purpose register or a memory location. The action of this instruction depends on the operand size (dividend/divisor). See the table above. Non-integral results are truncated (chopped) towards 0. The remainder is always less than the divisor in magnitude. Overflow is indicated with the #DE (divide error) exception rather than with the CF flag.

The CF, OF, SF, ZF, AF, and PF flags are undefined.

AL AH = AH:AL/operand : byte
AX DX = DX:AX/operand : WORD
EAX EDX = EDX:EAX/operand : DWORD
RAX RDX = RDX:RAX/operand : QWORD

Command Parameters

Parameter	Description
operand	The dividend operand

Examples

div ecx

mov eax,6
mov edx,0
mov ecx,2
div ecx
// eax = 3, edx = 0

mov eax,9
mov edx,0
mov esi,2
div esi
// eax = 4, edx = 1

mov eax,0
mov edx,1
mov esi,0x10
div esi
// eax = 0x10000000, edx = 0

mov eax,6
mov edx,0
mov [00123ABC],2
div [00123ABC]
// eax = 6, edx = 0

mov eax,6
mov edx,0
mov [SomeSymbol],2
div [SomeSymbol]
// eax = 6, edx = 0

See also

• Assembler
• Auto Assembler
• Assembler Commands

External links

• wikipedia.org/wiki/X86_instruction_listings
• wikibooks.org/wiki/X86_Assembly/Other_Instructions
• asmpedia.org
• x86.renejeschke.de/html/file_module_x86_id_72.html