Samsung S3C84E5 user manual ADC Add with Carry, Adc

INSTRUCTION SET S3C84E5/C84E9/P84E9

ADC — Add with Carry

ADC	dst,src
Operation:	dst ← dst + src + c
	The source operand, along with the carry flag setting, is added to the destination operand and the
	sum is stored in the destination. The contents of the source are unaffected. Two's-complement
	addition is performed. In multiple-precision arithmetic, this instruction lets the carry value from the
	addition of low-order operands be carried into the addition of high-order operands.
Flags:	C: Set if there is a carry from the most significant bit of the result; cleared otherwise.
	Z: Set if the result is "0"; cleared otherwise.
	S: Set if the result is negative; cleared otherwise.

V:Set if arithmetic overflow occurs, that is, if both operands are of the same sign and the result is of the opposite sign; cleared otherwise.

D:Always cleared to "0".

H:Set if there is a carry from the most significant bit of the low-order four bits of the result; cleared otherwise.

Format:

			Bytes	Cycles	Opcode	Addr Mode
					(Hex)	dst	src
opc	dst src		2	4	12	r	r
				6	13	r	lr
opc	src	dst	3	6	14	R	R
					15	R	IR
opc	dst	src	3	6	16	R	IM

Examples: Given: R1 = 10H, R2 = 03H, C flag = "1", register 01H = 20H, register 02H = 03H, and register 03H = 0AH:

ADC	R1,R2	→	R1	= 14H, R2 = 03H
ADC	R1,@R2	→	R1	= 1BH, R2 = 03H
ADC	01H,02H	→	Register 01H		=	24H, register 02H	=	03H
ADC	01H,@02H	→	Register 01H		=	2BH, register 02H	=	03H
ADC	01H,#11H	→	Register 01H		=	32H

In the first example, the destination register R1 contains the value 10H, the carry flag is set to "1" and the source working register R2 contains the value 03H. The statement "ADC R1,R2" adds 03H and the carry flag value ("1") to the destination value 10H, leaving 14H in the register R1.

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