INSTRUCTION SET

S3C84E5/C84E9/P84E9

 

 

JR — Jump Relative

JRcc,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)

cc opc

dst

 

 

Bytes

Cycles

Opcode

Addr Mode

 

 

(Hex)

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.

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Samsung S3C84E5 user manual JR Jump Relative, Hex Dst CcB Cc = 0 to F, Jr C,Labelx