Executing misaligned load dependent instruction in second execution stage in parity protected mode in configurable pipelined processor
A method includes providing a data processor having an instruction pipeline, where the instruction pipeline has a plurality of instruction pipeline stages, and where the plurality of instruction pipeline stages includes a first instruction pipeline stage and a second instruction pipeline stage. The method further includes providing a load instruction and a data-dependent instruction to the instruction pipeline. Based on an operating mode, such as ECC mode or parity mode, the data-dependent instruction may execute in either the first of the second instruction pipeline stage. Further, the execution of the data-dependent instruction may depend on whether the most recently executed instruction was misaligned.
1. A method, comprising:
providing a data processor having an instruction pipeline, wherein the instruction pipeline has a plurality of instruction pipeline stages, and wherein the plurality of instruction pipeline stages comprise a first instruction pipeline stage and a second instruction pipeline stage;
providing a load instruction to the instruction pipeline;
providing a data-dependent instruction to the instruction pipeline;
executing the data-dependent instruction in the first instruction pipeline stage if a most recently executed instruction was the load instruction and if the most recently executed instruction was for aligned memory access;
executing the data-dependent instruction in the second instruction pipeline stage if the most recently executed instruction was the load instruction and if the most recently executed instruction was for misaligned memory access and if a first mode is selected; and
executing the data-dependent instruction in the first instruction pipeline stage if the most recently executed instruction was the load instruction and if the most recently executed instruction was for misaligned memory access and if a second mode is selected.
2. A method as in claim 1 , wherein the first mode comprises a parity protected mode and the second mode comprises an error correction code (ECC) protected mode.
3. A method as in claim 1 , wherein the data-dependent instruction comprises an arithmetic instruction.
4. A method as in claim 1 wherein the data-dependent instruction comprises a logic instruction.
5. A method for executing instructions in a data processor having an instruction pipeline, wherein the instruction pipeline comprises a plurality of instruction pipeline stages including a first instruction pipeline stage and a second instruction pipeline stage, comprising:
providing a load instruction to the instruction pipeline;
providing a data-dependent instruction to the instruction pipeline;
determining an error detection mode operating on the instruction pipeline;
executing the data-dependent instruction in the first instruction pipeline stage if a most recently executed instruction was the load instruction and if the most recently executed instruction was for aligned memory access;
executing the data-dependent instruction in the second instruction pipeline stage if the most recently executed instruction was the load instruction and if the most recently executed instruction was for misaligned memory access and if the determined error detection mode is a parity protected mode.