It does not make sense to dedicate full read port for reading PC. Just run a bus directly from the register cells, which is exactly how it is done in ARM7TDMI in question.
Sure, but then you're half way to a special purpose register. And then you get to add in the logic to arbitrate writes from the GPR ports with reads from the PC-dedicated port. At which point you have more hardware complexity than just a dedicated SPR.
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It does not make sense to dedicate full read port for reading PC. Just run a bus directly from the register cells, which is exactly how it is done in ARM7TDMI in question.
Sure, but then you're half way to a special purpose register. And then you get to add in the logic to arbitrate writes from the GPR ports with reads from the PC-dedicated port. At which point you have more hardware complexity than just a dedicated SPR.