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INSTRUCTION SET S3C84E5/C84E9/P84E9
6-48
JR — Jump Relative
JR cc,dst
Operation: If cc is true, PC ← PC + dst
If the condition specified by the condition code (cc) is true, 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 JR instruction is executed. (See the list of condition codes at
the beginning of this chapter).
The range of the relative address is +127, –128, and the original value of the program counter is
taken to be the address of the first instruction byte following the JR statement.
Flags: No flags are affected.
Format:
(note)
Bytes Cycles Opcode
(Hex)
Addr Mode
dst
cc | opc dst 2 6 ccB RA
cc = 0 to F
NOTE: In the first byte of the two-byte instruction format, the condition code and the opcode are each four
bits in length.
Example: Given: The carry flag = "1" and LABEL_X = 1FF7H:
JR C,LABEL_X → PC = 1FF7H
If the carry flag is set (that is, if the condition code is “true”), the statement "JR C,LABEL_X" will
pass control to the statement whose address is currently in the program counter. Otherwise, the
program instruction following the JR will be executed.