There are some other of Intel's x86 lines that don't have a register file in their internal design, Geode GX and Vortex86 and many embedded processors that aren't Pentium-compatible or reverse-engineered early 80x86 processors. Therefore, most of them don't have a register file for their decoders, but their GPRs are used individually. Pentium 4, on the other hand, does not have a register file for its decoder, as its x86 GPRs didn't exist within its structure, due to the introduction of a physical unified renaming register file (similar to Sandy Bridge, but slightly different due to the inability of Pentium 4 to use the register before naming) for attempting to replace the architectural register file and skip the x86 decoding scheme. Instead it uses SSE for integer execution and storage before the ALU and after result, SSE2/SSE3/SSSE3 use the same mechanism as well for its integer operation.