Cpijne Compare, Increment, And Jump On Non-Equal - Samsung S3C80A5B User Manual

INSTRUCTION SET
CPIJNE
— Compare, Increment, and Jump on Non-Equal
CPIJNE dst,src,RA
If dst – src "0", PC ← PC + RA
Operation:
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
NOTE:
Example: Given: R1 = 02H, R2 = 03H, and register 03H = 04H:
CPIJNE R1,@R2,SKIP
Working register R1 contains the value 02H, working register R2 (the source pointer) the value 03H,
and 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 must be within the allowed range of + 127 to – 128.)
6-32
src dst RA
Execution time is 18 cycles if the jump is taken or 16 cycles if it is not taken.
→ R2 = 04H, PC jumps to SKIP location
Bytes Cycles Opcode
3 12
S3C80A5B
Addr Mode
(Hex) dst src
D2 r Ir