| 摘要 |
PROBLEM TO BE SOLVED: To provide an effective method for extending an instruction set without increasing complexity of hardware. SOLUTION: A method, apparatus and system are disclosed for decoding an instruction in a variable-length instruction set. The instruction is one of a set of new types of instructions that uses a new escape code value, which is two bytes in length, to indicate that a third opcode byte includes the instruction-specific opcode for a new instruction. The new instructions are defined such that the length of each instruction in the opcode map for one of the new escape opcode values may be determined using the same set of inputs, where each of the inputs is relevant for determining the length of each instruction in the new opcode map. For at least one embodiment, the length of one of the new instructions is determined without evaluating the instruction-specific opcode. COPYRIGHT: (C)2005,JPO&NCIPI |
