Intel 80C188XL, 80C186XL Instruction Set Descriptions, Table C-4.Instruction Set Continued, C-31

INSTRUCTION SET DESCRIPTIONS

Table C-4. Instruction Set (Continued)

Name	Description	Operation	Flags
			Affected
NEG	Negate:	When Source Operand is a Byte:	AF
	NEG dest	(dest) ← FFH – (dest)	CF
			DF –
	Subtracts the destination operand,	(dest) ← (dest) + 1 (affecting flags)
			IF –
	which may be a byte or a word, from 0	When Source Operand is a Word:
			OF
	and returns the result to the desti-	(dest) ← FFFFH – (dest)
			PF
	nation. This forms the two's
		(dest) ← (dest) + 1 (affecting flags)	SF
	complement of the number, effectively
			TF –
	reversing the sign of an integer. If the
			ZF ¸
	operand is zero, its sign is not
	changed. Attempting to negate a byte
	containing –128 or a word containing –
	32,768 causes no change to the
	operand and sets OF.
	Instruction Operands:
	NEG reg
	NEG mem
NOP	No Operation:	None	AF –
	NOP		CF –
			DF –
	Causes the CPU to do nothing.
			IF –
	Instruction Operands:
			OF –
	none		PF –
			SF –
			TF –
			ZF –
NOT	Logical Not:	When Source Operand is a Byte:	AF –
	NOT dest	(dest) ← FFH – (dest)	CF –
			DF –
	Inverts the bits (forms the one's	When Source Operand is a Word:
			IF –
	complement) of the byte or word	(dest) ← FFFFH – (dest)
			OF –
	operand.
			PF –
	Instruction Operands:
			SF –
	NOT reg		TF –
	NOT mem		ZF –

NOTE: The three symbols used in the Flags Affected column are defined as follows:

–the contents of the flag remain unchanged after the instruction is executed ¸? the contents of the flag is undefined after the instruction is executed

the flag is updated after the instruction is executed

C-31