Intel 80286, 80287 manual IDIV-Signed Divide

THE 80286 INSTRUCTION SET

IDIV-Signed Divide

Opcode		Instruction	Clocks	Description
F6	/7	IDIVeb	17,mem=20	Signed divide AX byEA byte (AL=Quo,
				AH=Rem)
F7	/7	IDIVew	25,mem=28	Signed divide DX:AX by EA word (AX=Quo,
				DX=Rem)

/

FLAGS MODIFIED

None

FLAGS UNDEFINED

Overflow, sign, zero, auxiliary carry, parity, carry

OPERATION

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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