debug/fmv: always-on CD data-ready + CD-IRQ-delivery counters in fmv_state

Add two always-on counters (per the no-printf / ring-buffer rule) to diagnose the
MMX5 intro-FMV stall:
- cdrom.c: s_dataready_fires — CD INT1 (data-ready) raised per streamed sector,
  exposed via cdrom_get_dataready_fires().
- interrupts.c: g_cdrom_deliver_count — CD IRQ (IRQ_CDROM) exceptions actually
  taken by the guest.
Both surfaced in the fmv_state debug command (cd_dataready_fires / cd_irq_delivered).

These proved CD INT1 + CD-IRQ delivery are NOT the MMX5 FMV blocker (fires=627,
delivered=746 during the movie while the STR ring still never commits a frame) —
narrowing the bug to the CD-DMA-ch3-completion -> frame-commit path. Harmless
observability; no behavior change.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

runtime/src/cdrom.c

@@ -892,6 +892,9 @@ static int data_fifo_ready(void) {
            sector_read_pos < sector_size;
 }
 
+static uint64_t s_dataready_fires;  /* INT1 (data-ready) raised per streamed sector — FMV dispatch probe */
+uint64_t cdrom_get_dataready_fires(void) { return s_dataready_fires; }
+
 static int deliver_read_sector(void) {
     int delivered = read_sector_at(read_min, read_sec, read_sect);
     advance_msf(&read_min, &read_sec, &read_sect);
@@ -900,6 +903,7 @@ static int deliver_read_sector(void) {
     response_push(stat_reg);
     set_irq(CDIRQ_DATA_READY);
     fire_cdrom_irq();
+    s_dataready_fires++;
     return 1;
 }
 

runtime/src/debug_server.c

@@ -9172,6 +9172,8 @@ static void handle_fmv_state(int id, const char *json)
     extern uint32_t mdec_get_decode_count(void);
     extern int cdrom_xa_stream_active(void);
     extern uint16_t sio_get_pad_buttons(void);
+    extern uint64_t cdrom_get_dataready_fires(void);
+    extern uint64_t g_cdrom_deliver_count;
     int auto_skip = -1; uint32_t total_table = 0, movie_id = 0; const char *cfg = "(null)";
     debug_get_fmv_config(&auto_skip, &total_table, &movie_id, &cfg);
     MDECDebugState s; mdec_debug_get_state(&s);
@@ -9181,11 +9183,14 @@ static void handle_fmv_state(int id, const char *json)
              "\"fmv_skip_total_table\":\"0x%08X\",\"fmv_skip_movie_id\":\"0x%08X\","
              "\"mdec_decode_count\":%u,\"mdec_decode_macroblocks\":%u,\"mdec_dma_out_words\":%u,"
              "\"xa_stream_active\":%d,"
+             "\"cd_dataready_fires\":%llu,\"cd_irq_delivered\":%llu,"
              "\"pad1\":\"0x%04X\"}",
              id, cfg ? cfg : "(null)", auto_skip,
              total_table, movie_id,
              mdec_get_decode_count(), s.decode_macroblocks, s.dma_out_words,
              cdrom_xa_stream_active(),
+             (unsigned long long)cdrom_get_dataready_fires(),
+             (unsigned long long)g_cdrom_deliver_count,
              (unsigned)(sio_get_pad_buttons() & 0xFFFFu));
 }
 

runtime/src/interrupts.c

@@ -375,6 +375,7 @@ uint64_t g_nestgate_depth, g_nestgate_rfepend, g_nestgate_escreason, g_nestgate_
 uint64_t g_vblank_raise_count   = 0;  /* bit0 set at the cycle-paced raise site */
 uint64_t g_vblank_deliver_count = 0;  /* VBLANK delivered to the guest (exception taken) */
 uint64_t g_irq_deliver_count    = 0;  /* ANY hardware interrupt delivered */
+uint64_t g_cdrom_deliver_count  = 0;  /* CD IRQ (IRQ_CDROM) delivered to the guest — FMV dispatch probe */
 extern uint64_t g_vblank_ack_count;   /* defined in memory.c */
 
 /* Blocks of guaranteed main-code forward progress imposed after a CLAIMED
@@ -766,6 +767,7 @@ void psx_check_interrupts(CPUState* cpu) {
     }
     g_irq_deliver_count++;
     if ((i_stat & i_mask) & (1u << IRQ_VBLANK)) g_vblank_deliver_count++;
+    if ((i_stat & i_mask) & (1u << IRQ_CDROM))  g_cdrom_deliver_count++;
     /* IRQ-delivery context ring (MMX6 VSync-vs-CD-DMA hunt). Capture, at every IRQ
      * delivery, whether the kernel VSync callback-block word at 0x80079D44 is the
      * clobbered game value AND whether a CD DMA (ch3) is mid-transfer / a DMA is