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>
Framework work on codex/mmx6-support that makes Tomba build and play
(title screen, 0 dispatch misses) and MMX6 boot through BIOS to its
intro. Touches recompiler codegen (code_generator, function_analysis)
and runtime CD-ROM/DMA/MDEC/GPU/SIO timing (cdrom, dma, mdec, gpu,
psx_cycles, traps, fntrace, debug_server) + headers + runtime.cmake.
Milestone snapshot for collapsing onto master. Build dir excluded.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The "v4" suffix was a holdover from iterative project restarts.
There is now one psxrecomp; all identifiers, include guards, cmake
variables, function names, log strings, schema tags, and tool paths
drop the v4 suffix.
Changes:
- PSXRECOMP_V4_ROOT → PSXRECOMP_ROOT (cmake)
- PSXRECOMP_V4_RUNTIME_SOURCES/_INCLUDE_DIRS/_BIOS_GENERATED → no V4
- psxrecomp_v4_add_runtime_target → psxrecomp_add_runtime_target
- PSXRECOMP_V4_*_H include guards → PSXRECOMP_*_H
- "psxrecomp-v4" log/window strings → "psxrecomp"
- Schema version strings in recompiler JSON output
- Tool script hardcoded absolute paths updated
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
timers.c — timers_advance(cycles) replaces per-frame timers_tick().
Per-timer fractional accumulator + proper divisors:
- Timer 0 dotclock approx (cycles/5)
- Timer 1 HBlank clock (cycles/2146, ~263 HBlanks per NTSC frame)
- Timer 2 SYSCLK or SYSCLK/8 per mode register bit 8..9
Target/overflow flags fire IRQ when bit 4/5 of mode is set.
cdrom.c — cdrom_advance(cycles) replaces per-frame cdrom_tick().
Sector pacing from CPU clock: 451584 cycles at 1x, 225792 at 2x
(SetMode bit 7). Whole-sector mode bit 5 prepends a 12-byte BCD-MSF
header to the data buffer; SECTOR_BUFFER_SIZE = 12 + 2048.
cdrom_trace ring: always-on CDROMTraceEntry[1<<16] capturing every
register write, IRQ raise/mask, sector load, and command dispatch
with the current func/PC/frame snapshot. Query via the new
debug_server commands landed in a later commit.
psx_cycles.c — psx_advance_cycles now drives cdrom_advance and
timers_advance in addition to sio_advance.
interrupts.c — legacy per-frame timers_tick + cdrom_tick now gated
behind #ifndef PSX_ENABLE_BLOCK_CYCLES, so block-cycle builds use
the cycle-paced path exclusively.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Matthew Stanley