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2015-07-17x86: decode instructions with vex prefixNilay Vaish
This patch updates the x86 decoder so that it can decode instructions with vex prefix. It also updates the isa with opcodes from vex opcode maps 1, 2 and 3. Note that none of the instructions have been implemented yet. The implementations would be provided in due course of time.
2014-12-04x86: Rework opcode parsing to support 3 byte opcodes properly.Gabe Black
Instead of counting the number of opcode bytes in an instruction and recording each byte before the actual opcode, we can represent the path we took to get to the actual opcode byte by using a type code. That has a couple of advantages. First, we can disambiguate the properties of opcodes of the same length which have different properties. Second, it reduces the amount of data stored in an ExtMachInst, making them slightly easier/faster to create and process. This also adds some flexibility as far as how different types of opcodes are handled, which might come in handy if we decide to support VEX or XOP instructions. This change also adds tables to support properly decoding 3 byte opcodes. Before we would fall off the end of some arrays, on top of the ambiguity described above. This change doesn't measureably affect performance on the twolf benchmark. --HG-- rename : src/arch/x86/isa/decoder/three_byte_opcodes.isa => src/arch/x86/isa/decoder/three_byte_0f38_opcodes.isa rename : src/arch/x86/isa/decoder/three_byte_opcodes.isa => src/arch/x86/isa/decoder/three_byte_0f3a_opcodes.isa
2012-05-26CPU: Merge the predecoder and decoder.Gabe Black
These classes are always used together, and merging them will give the ISAs more flexibility in how they cache things and manage the process. --HG-- rename : src/arch/x86/predecoder_tables.cc => src/arch/x86/decoder_tables.cc