F6 /7         IDIV r/m8                 Signed divide AX (where AH must contain sign-extension

                       of AL) by r/m byte. (Results: AL=Quotient,

                       AH=Remainder)

F7 /7        IDIV r/m16         Signed divide DX:AX (where DX must contain sign-extension

                       of AX) by r/m word. (Results: AX=Quotient,

                       DX=Remainder)

F7 /7         IDIV r/m32         Signed divide EDX:EAX (where EDX must contain

                       sign-extension of EAX) by r/m doubleword. (Results:

                       EAX=Quotient, EDX=Remainder)


Description

Divides (signed) the value in the AL, AX, or EAX register by the source operand and stores the result in the AX, DX:AX, or EDX:EAX registers. The source operand can be a general-purpose register or a memory location. The action of this instruction depends on the operand size, as shown in the following table:


Operand Size         Dividend         Divisor         Quotient         Remainder         Quotient Range

Word/byte         AX                 r/m8         AL                 AH                 −128 to +127

Doubleword/word         DX:AX                 r/m16         AX                 DX                 −32,768 to +32,767

Quadword/

  doubleword         EDX:EAX                 r/m32         EAX                 EDX                 −2 31 to 2 32 − 1


Non-integral results are truncated (chopped) towards 0. The sign of the remainder is always the same as the sign of the dividend. The absolute value of the remainder is always less than the absolute value of the divisor. Overflow is indicated with the #DE (divide error) exception rather than with the OF (overflow) flag.


Operands        Bytes                Clocks

r8                  2                  22   NP

r16                 2                   30   NP

r32                 2                    46   NP

mem8           2+d(0-2)         22   NP

mem16          2+d(0-2)         30   NP

mem32          2+d(0-2)         46   NP


implied        operand        quotient        remainder

dividend

AX                      /  byte               = AL             AH

DX:AX           /  word               = AX             DX

EDX:EAX         /  dword              = EAX             EDX


Flags

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

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