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Old 2009-02-20, 22:07   #6
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Oct 2004

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Anyone who is interested in these sorts of issues could look at some of the work of the F-CPU project, which is (was?) an attempt to design a general-purpose 64-bit CPU from scratch, with SIMD designed in from the ground up. Because the first implementations needed to be efficient on FPGAs, and these have a strict limit on the number of read and write ports to the logic you would use for register files, the instruction set has many instructions that write two registers (e.g. a sum and a carry out in register (X) and (X XOR 1), respectively). I don't envy whoever tried to modify gcc to emit code for it :)
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