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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: 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 = 04H:
CPIJNE
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
R1,@R2,SKIP →
S3C8248/C8245/P8245/C8247/C8249/P8249
Bytes
Cycles
3
12
R2 = 04H, PC jumps to SKIP location
Opcode
Addr Mode
(Hex)
dst
src
D2
r
Ir
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