Context Switch Optimization

In an embodiment, a processor may include a register file including one or more sets of registers for one or more data types specified by the ISA implemented by the processor. The processor may have a processor mode in which the context is reduced, as compared to the full context. For example, for at least one of the data types, the registers included in the reduced context exclude one or more of the registers defined in the ISA for that data type. In an embodiment, one half or more of the registers for the data type may be excluded. When the processor is operating in a reduced context mode, the processor may detect instructions that use excluded registers, and may signal an exception for such instructions to prevent use of the excluded registers.