cdrom: adjust a timing hack

notaz/pcsx_rearmed#276

diff --git a/libpcsxcore/cdrom.c b/libpcsxcore/cdrom.c
index 10fc615..098b77d 100644 (file)
--- a/libpcsxcore/cdrom.c
+++ b/libpcsxcore/cdrom.c
@@ -1503,14 +1503,22 @@ void cdrWrite3(unsigned char rt) {
                break; // transfer
        case 1:
                if (cdr.Stat & rt) {
+                       u32 nextCycle = psxRegs.intCycle[PSXINT_CDR].sCycle
+                               + psxRegs.intCycle[PSXINT_CDR].cycle;
 #ifdef CDR_LOG_CMD_IRQ
-                       SysPrintf("%u cdrom: ack %02x (w %02x)\n",
-                               psxRegs.cycle, cdr.Stat & rt, rt);
+                       SysPrintf("%u cdrom: ack %02x (w=%02x p=%d,%d)\n",
+                               psxRegs.cycle, cdr.Stat & rt, rt,
+                               !!(psxRegs.interrupt & (1 << PSXINT_CDR)),
+                               nextCycle - psxRegs.cycle);
 #endif
-                       // note: Croc vs Discworld Noir
+                       // note: Croc, Shadow Tower (more) vs Discworld Noir (<993)
                        if (!(psxRegs.interrupt & (1 << PSXINT_CDR)) &&
                            (cdr.CmdInProgress || cdr.Irq1Pending))
-                               CDR_INT(850); // 711-993
+                       {
+                               s32 c = 2048 - (psxRegs.cycle - nextCycle);
+                               c = MAX_VALUE(c, 512);
+                               CDR_INT(c);
+                       }
                }
                cdr.Stat &= ~rt;