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S3C8235B/F8235B INSTRUCTION SET JP — JUMP JP cc,dst (Conditional) JP dst (Unconditional) Operation: If cc is true, PC ← dst The conditional JUMP instruction transfers program control to the destination address if the condition specified by the condition code (cc) is true, otherwise, the instruction following the JP instruction is executed. The unconditional JP simply replaces the contents of the PC with the contents of the specified register pair. Control then passes to the statement addressed by the PC. Flags: No flags are affected. Format: (1) Bytes Cycles Opcode (Hex) Addr Mode dst 3 8 ccD DA (2) cc | opc dst cc = 0 to F opc dst 2 8 30 IRR NOTES: 1. The 3-byte format is used for a conditional jump and the 2-byte format for an unconditional jump. 2. In the first byte of the 3-byte instruction format (conditional jump), the condition code and the OPCODE are both four bits. Examples: Given: The carry flag (C) = "1", register 00 = 01H, and register 01 = 20H:Secs JP C,LABEL_W JP @00H → → LABEL_W = 1000H, PC = 1000H PC = 0120H The first example shows a conditional JP. Assuming that the carry flag is set to "1", the statement "JP C,LABEL_W" replaces the contents of the PC with the value 1000H and transfers control to that location. Had the carry flag not been set, control would then have passed to the statement immediately following the JP instruction. The second example shows an unconditional JP. The statement "JP @00" replaces the contents of the PC with the contents of the register pair 00H and 01H, leaving the value 0120H. 6-47