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24 lines
760 B
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24 lines
760 B
Plaintext
This directory contains mpn functions optimized for MIPS3. Example of
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processors that implement MIPS3 are R4000, R4400, R4600, R4700, and R8000.
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RELEVANT OPTIMIZATION ISSUES
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1. On the R4000 and R4400, branches, both the plain and the "likely" ones,
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take 3 cycles to execute. (The fastest possible loop will take 4 cycles,
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because of the delay insn.)
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On the R4600, branches takes a single cycle
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On the R8000, branches often take no noticable cycles, as they are
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executed in a separate function unit..
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2. The R4000 and R4400 have a load latency of 4 cycles.
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3. On the R4000 and R4400, multiplies take a data-dependent number of
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cycles, contrary to the SGI documentation. There seem to be 3 or 4
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possible latencies.
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STATUS
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Good...
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