User's Manual

THE 80286 INSTRUCTION SET
IDIV -Signed Divide
Opcode
F6 /7
F7 /7
FLAGS MODIFIED
None
Instruction
IDIVeb
IDIVew
FLAGS UNDEFINED
Clocks
17,mem=20
25,mem=28
Overflow, sign, zero, auxiliary carry, parity, carry
OPERATION
Description
Signed divide AX byEA byte (AL=Quo,
AH=Rem)
Signed divide DX:AX by EA word (AX=Quo,
DX=Rem)
/
IDlY performs a signed divide. The dividend is implicit; only the divisor is given as an operand. If the
source operand
is a BYTE operand, divide AX by the byte. The quotient is· stored in AL, and the
remainder
is stored in AH. If the source operand is a WORD operand, divide DX:AX by the word.
The high-order
16 bits of the dividend are in DX. The quotient is stored in AX, and the remainder is
stored in DX. Non-integral quotients are truncated towards o. The remainder has the same sign as the
dividend
and always has less magnitude than the dividend.
PROTECTED MODE EXCEPTIONS
Interrupt 0 if the quotient is too big to fit in the designated register (AL or AX), 'or if the divisor is O.
#GP(O) for an illegal memory operand effective address in the CS, DS, or ES segments; #SS(O) for an
illegal address in the SS segment. . .
REAL ADDRESS MODE EXCEPTIONS
InterJillpt 0 if the quotient is too big to fit in. the designated register (AL or AX), orif the divisor is O.
Interrupt 13 for a word operand at offset OFFFFH.
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