Intel 80C188XL, 80C186XL user manual Subtract, SUB dest, src, Test

INSTRUCTION SET DESCRIPTIONS

Table C-4. Instruction Set (Continued)

Name	Description	Operation	Flags
			Affected
SUB	Subtract:	(dest) ← (dest) – (src)	AF
	SUB dest, src		CF
			DF –
	The source operand is subtracted from
			IF –
	the destination operand, and the result
			OF
	replaces the destination operand. The
			PF
	operands may be bytes or words. Both
			SF
	operands may be signed or unsigned
			TF –
	binary numbers (see AAS and DAS).
			ZF ¸
	Instruction Operands:
	SUB reg, reg
	SUB reg, mem
	SUB mem, reg
	SUB accum, immed
	SUB reg, immed
	SUB mem, immed
TEST	Test:	(dest) and (src)	AF ?
	TEST dest, src	(CF ) ← 0	CF
		(OF) ← 0	DF –
	Performs the logical "and" of the two
			IF –
	operands (bytes or words), updates
			OF
	the flags, but does not return the
			PF
	result, i.e., neither operand is
			SF
	changed. If a TEST instruction is
			TF –
	followed by a JNZ (jump if not zero)
			ZF ¸
	instruction, the jump will be taken if
	there are any corresponding one bits
	in both operands.
	Instruction Operands:
	TEST reg, reg
	TEST reg, mem
	TEST accum, immed
	TEST reg, immed
	TEST mem, immed

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

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