mirror of
https://github.com/RetroPortingToolKit/psxrecomp
synced 2026-10-27 10:38:46 -04:00
Matthew Stanley
2d915c3fa9
Phase 1 of the cycle-budgeted precise interrupt-take-point fix (root cause: compiled blocks take IRQs only at block edges; HW + the dirty-RAM interpreter take them at the exact instruction — oracle-confirmed at the Tomba 2 logo Timer1 debounce). Design validated with ChatGPT; full spec in PRECISE_IRQ_SLICE.md. This commit lands the additive, no-behavior-change foundation (Task #2) plus the prior session's diagnostic take-PC capture, and a build-hygiene dedup: - cycles_to_next_event() (interrupts.c): single source of truth — min guest-cycle distance to the next DELIVERABLE interrupt (source raises its I_STAT bit AND that bit is unmasked in i_mask). Aggregates VBLANK + per-peripheral queries. - timers/cdrom/dma/sio _cycles_to_irq(i_mask): each peripheral owns its own next-IRQ-distance query; all conservative under-estimates (smaller => slice more => never run past an event). - debug_server: cycles_to_next_event command for live validation. - interrupts.c: take-PC capture into the IRQ_DELIVER event-ring aux (prior session's diagnostic; records the architectural take-PC for cross-backend diff). - overlay_loader.c: remove duplicate psx_native_bad_entry definition (HEAD had it twice; would not link cleanly). Live-validated at the logo: returns the VBLANK distance, correctly excludes the three free-running (unarmed/masked) timers and idle CD/DMA/SIO. Runtime-only, no regen. The two-tier executor (Task #3) that consumes this is next. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
84 lines
3.2 KiB
C
84 lines
3.2 KiB
C
#ifndef PSXRECOMP_INTERRUPTS_H
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#define PSXRECOMP_INTERRUPTS_H
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#include <stdint.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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struct CPUState;
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/* IRQ bit positions in I_STAT/I_MASK */
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#define IRQ_VBLANK 0
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#define IRQ_GPU 1
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#define IRQ_CDROM 2
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#define IRQ_DMA 3
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#define IRQ_TIMER0 4
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#define IRQ_TIMER1 5
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#define IRQ_TIMER2 6
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#define IRQ_SIO0 7
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#define IRQ_SIO1 8
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#define IRQ_SPU 9
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#define IRQ_PIO 10
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void interrupts_init(void);
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/* Called from the dispatch loop after each function returns.
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* Fires vblank on schedule, checks (i_stat & i_mask), and if
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* pending + COP0 allows, dispatches the exception handler. */
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void psx_check_interrupts(struct CPUState* cpu);
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/* Interrupt check with the compiled guest PC to resume if a game-installed
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* handler later RFEs to the sentinel outside the synchronous host window. */
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void psx_check_interrupts_at(struct CPUState* cpu, uint32_t resume_pc);
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/* Accumulate emitted PSX cycles toward the next VBlank trigger.
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* Called from psx_advance_cycles() so the VBlank rate is gated on
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* guest cycles (correct PSX timing) rather than block-dispatch
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* count (which was 5-6x too fast and squeezed game-time to ~60% of
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* real). One real-PSX VBlank = 564480 cycles (33.8688 MHz / 60). */
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void interrupts_advance_cycles(uint32_t cycles);
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/* Cycle-budgeted precise event slicing: minimum guest-CPU-cycle distance to the
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* next DELIVERABLE hardware interrupt (source raises its I_STAT bit AND that bit
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* is unmasked in i_mask). UINT32_MAX if none scheduled. Single source of truth
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* for the two-tier block executor's fast/slice decision. See PRECISE_IRQ_SLICE.md. */
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uint32_t cycles_to_next_event(void);
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/* Query whether we are currently inside an exception handler dispatch. */
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int psx_get_in_exception(void);
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/* Snapshot internal counters for the freeze_check diagnostic. Any out_*
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* pointer may be NULL. All counters are monotonically non-decreasing
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* (dispatch_count resets each VBlank). */
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void psx_get_freeze_diag(uint64_t *out_total_checks,
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uint32_t *out_dispatch_count,
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int *out_in_exception,
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int *out_post_exc_cooldown,
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uint64_t *out_exc_entries,
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uint64_t *out_exc_reentry_blocks);
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/* longjmp back to psx_check_interrupts, unwinding the exception handler.
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* Called by ReturnFromException (B0:0x17 or SYSCALL(3)) when inside
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* the exception handler to model real hardware's RFE+JR $k0 unwind. */
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void psx_exception_longjmp(void);
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/* longjmp back to psx_check_interrupts for RestoreState redirection.
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*
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* On real hardware, RestoreState (A0:0x14) restores all GPRs from a
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* save buffer and does `jr $ra`, which jumps to the restored $ra —
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* abandoning the current call stack. In our model, a plain `return;`
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* would go back to the C caller (the chain walker), not to $ra.
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*
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* This function longjmps with code 2 (vs. 1 for ReturnFromException),
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* so psx_check_interrupts can re-dispatch to cpu->pc while still in
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* exception context. The redirected code (e.g., VSync callback loop)
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* will eventually call ReturnFromException (longjmp code 1) to exit. */
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void psx_restore_state_escape(void);
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#ifdef __cplusplus
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}
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#endif
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#endif /* PSXRECOMP_INTERRUPTS_H */
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