S3 ViRGE: Add cycle timing to MMIO read functions to fix polling performance issue#6651
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Added wait states for MMIO reads to reduce excessive polling.
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Summary
Games that poll the S3 ViRGE status registers via MMIO (such as Star Trek: Generations) experience extreme slowdowns, particularly with the GX2 variant. Profiling revealed that and related functions were consuming ~25% of CPU time due to tight polling loops executing millions of iterations per second. s3_virge_mmio_read.
Root Cause
The MMIO read functions were missing cycle timing, so any polling loop on the status registers would run at unrealistic speeds. The palette fading in Raptor probably hammers those registers waiting for the GPU to be ready, causing the same issue. This fix adds proper wait states to all MMIO reads, which should resolve it.
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