Samsung S3F80JB manual Cpije Compare, Increment, and Jump on Equal

S3F80JBINSTRUCTION SET

CPIJE — Compare, Increment, and Jump on Equal

CPIJE	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 "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 immediately following the
	CPIJE instruction is executed. In either case, the source pointer is incremented by one before the
	next instruction is executed.

Flags: No flags are affected.

Format:

opc src dst RA

Bytes	Cycles	Opcode	Addr Mode
		(Hex)	dst	src
3	12	C2	r	Ir

NOTE: Execution time is 18 cycles if the jump is taken or 16 cycles if it is not taken.

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

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

In this example, working register R1 contains the value 02H, working register R2 the value 03H, and register 03 contains 02H. The statement "CPIJE R1,@R2,SKIP" compares the @R2 value 02H (00000010B) to 02H (00000010B). Because the result of the comparison is equal, the relative address is added to the PC and the PC then jumps to the memory location pointed to by SKIP. The source register (R2) is incremented by one, leaving a value of 04H. (Remember that the memory location must be within the allowed range of + 127 to – 128.)

6-31