Samsung S3C84E5 user manual Cpijne Compare, Increment, and Jump on Non-Equal, Opc Src Dst

INSTRUCTION SET S3C84E5/C84E9/P84E9

CPIJNE — Compare, Increment, and Jump on Non-Equal

CPIJNE	dst,src,RA
Operation:	If dst–src ¡	"0", PC	← PC + RA
	Ir	← Ir +	1

The source operand is compared to (subtracted from) the destination operand. If the result is not "0", the relative address is added to the program counter and control passes to the statement whose address is now in the program counter. Otherwise the instruction following the CPIJNE instruction is executed. In either case the source pointer is incremented by one before the next instruction.

Flags: No flags are affected.

Format:

opc src dst RA

Bytes	Cycles	Opcode	Addr Mode
		(Hex)	dst	src
3	12	D2	r	Ir

Example: Given: R1 = 02H, R2 = 03H, and register 03H = 04H:

CPIJNE R1,@R2,SKIP → R2 = 04H, PC jumps to SKIP location

The working register R1 contains the value 02H, the working register R2 (the source pointer) the value 03H, and the general register 03 the value 04H. The statement "CPIJNE R1,@R2,SKIP" subtracts 04H (00000100B) from 02H (00000010B). Because the result of the comparison is non- equal, the relative address is added to the PC and the PC then jumps to the memory location pointed to by SKIP. The source pointer register (R2) is also incremented by one, leaving a value of 04H.

Remember that the memory location addressed by the CPIJNE instruction must be within the allowed range of + 127 to – 128.

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