| 摘要 |
In a data processing system having a memory and employing N-bit bytes and two byte addresses, a branch instruction which can cross one page boundary is executed without having to use calculations to effect a change in the contents of the program counter (PC). It is determined whether the value V1 of the (N-1) least significant bits (LSB's ) of the lower order byte of the two byte branch address is greater or less than the value V2 of the (N-1) least significant bits (LSB's) of the lower order byte of the address to which the PC is pointing and also whether PC N NOTEQUAL BR N where PC N and BR N are the most significant bits of the lower order bytes of the PC address and the branch address, respectively. If V1<V2, PC N=1, and PC N NOTEQUAL BR N, the upper order byte of the PC address is incremented by 1 and if V1>V2, PC N=0, and PC N NOTEQUAL BR 7, the upper order byte of the PC address is decremented by 1.
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