S3C8245/P8245/C8249/P8249 INSTRUCTION SET
6-31
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:
Bytes Cycles Opcode
(Hex) Addr Mode
dst src
opc src dst RA 3 12 C2 rIr
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.)