Files
psxrecomp/runtime
Matthew Stanley ec1fd76b56 timing: faithful GTE (COP2) per-command completion-stall
Models the GTE command latency + stall-on-COP2-access, the next Stage-2 cycle
component. Mirrors the mult/div completion-stall mechanism:

- cpu->gte_ts_done (new CPUState field, appended): a GTE command sets it to
  psx_cycle_count + (cost-1); back-to-back commands serialize (psx_gte_set
  stalls to the prior deadline first). Any COP2 register access
  (MFC2/CFC2/MTC2/CTC2/LWC2/SWC2) calls psx_gte_stall, advancing guest cycles
  to the deadline if the op is still in flight.
- Cost table (psx_cycles.c, psx_gte_cmd_latency): per-op cost-1, transcribed +
  verified from beetle-psx gte.cpp op returns (RTPS15 NCLIP8 MVMVA8 NCDS19
  NCDT44 RTPT23 NCCT39 ... AVSZ4=5 not 6). cost-1 because the COP2 instruction's
  own +1 base is charged separately (Beetle GTE_Instruction returns ret-1).
- Set armed in the shared gte_execute() (one site for both backends); stall
  emitted before every COP2 reg access in both emitters (code_generator,
  strict_translator) and the dirty interp. The compiled "+1 at top" vs interp
  "base after exec_one" offset cancels (same as muldiv).

Validated EXACT on ruler #2 (new gte_rtps + gte_nclip loops): native +15/+8 ==
Beetle +15/+8. All other components unchanged (no regression); Tomba2 boots to
FMV. Requires regen (emitters changed); runtime+BIOS+game regenerated.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
2026-06-27 12:41:22 -07:00
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