cdrom: adjust a timing hack
[pcsx_rearmed.git] / libpcsxcore / cdrom.c
index a3ddb44..098b77d 100644 (file)
@@ -21,6 +21,7 @@
 * Handles all CD-ROM registers and functions.
 */
 
+#include <assert.h>
 #include "cdrom.h"
 #include "ppf.h"
 #include "psxdma.h"
@@ -35,7 +36,7 @@
 #if 0
 #define CDR_LOG_I SysPrintf
 #else
-#define CDR_LOG_I(...)
+#define CDR_LOG_I log_unhandled
 #endif
 #if 0
 #define CDR_LOG_IO SysPrintf
@@ -76,7 +77,7 @@ static struct {
        unsigned char ResultP;
        unsigned char ResultReady;
        unsigned char Cmd;
-       unsigned char unused4;
+       unsigned char SubqForwardSectors;
        unsigned char SetlocPending;
        u32 Reading;
 
@@ -89,8 +90,7 @@ static struct {
        boolean Play, Muted;
        int CurTrack;
        int Mode, File, Channel;
-       int Reset;
-       int NoErr;
+       unsigned char LocL[8];
        int FirstSector;
 
        xa_decode_t Xa;
@@ -208,6 +208,9 @@ unsigned char Test23[] = { 0x43, 0x58, 0x44, 0x32, 0x39 ,0x34, 0x30, 0x51 };
 // so (PSXCLK / 75) = cdr read time (linuzappz)
 #define cdReadTime (PSXCLK / 75)
 
+#define LOCL_INVALID 0xff
+#define SUBQ_FORWARD_SECTORS 2u
+
 enum drive_state {
        DRIVESTATE_STANDBY = 0, // pause, play, read
        DRIVESTATE_LID_OPEN,
@@ -243,8 +246,8 @@ static void sec2msf(unsigned int s, u8 *msf) {
        new_dyna_set_event(PSXINT_CDR, eCycle); \
 }
 
-// cdrPlaySeekReadInterrupt
-#define CDRPLAYSEEKREAD_INT(eCycle, isFirst) { \
+// cdrPlayReadInterrupt
+#define CDRPLAYREAD_INT(eCycle, isFirst) { \
        u32 e_ = eCycle; \
        psxRegs.interrupt |= (1 << PSXINT_CDREAD); \
        if (isFirst) \
@@ -295,8 +298,8 @@ static void setIrq(int log_cmd)
        if (cdr.Stat)
        {
                int i;
-               SysPrintf("CDR IRQ=%d cmd %02x stat %02x: ",
-                       !!(cdr.Stat & cdr.Reg2), log_cmd, cdr.Stat);
+               SysPrintf("%u cdrom: CDR IRQ=%d cmd %02x stat %02x: ",
+                       psxRegs.cycle, !!(cdr.Stat & cdr.Reg2), log_cmd, cdr.Stat);
                for (i = 0; i < cdr.ResultC; i++)
                        SysPrintf("%02x ", cdr.Result[i]);
                SysPrintf("\n");
@@ -308,6 +311,8 @@ static void setIrq(int log_cmd)
 // (yes it's slow, but you probably don't want to modify it)
 void cdrLidSeekInterrupt(void)
 {
+       CDR_LOG_I("%u %s cdr.DriveState=%d\n", psxRegs.cycle, __func__, cdr.DriveState);
+
        switch (cdr.DriveState) {
        default:
        case DRIVESTATE_STANDBY:
@@ -320,6 +325,7 @@ void cdrLidSeekInterrupt(void)
 
                if (stat.Status & STATUS_SHELLOPEN)
                {
+                       memset(cdr.Prev, 0xff, sizeof(cdr.Prev));
                        cdr.DriveState = DRIVESTATE_LID_OPEN;
                        CDRLID_INT(0x800);
                }
@@ -369,10 +375,14 @@ void cdrLidSeekInterrupt(void)
                break;
 
        case DRIVESTATE_PREPARE_CD:
-               cdr.StatP |= STATUS_SEEK;
-
-               cdr.DriveState = DRIVESTATE_STANDBY;
-               CDRLID_INT(cdReadTime * 26);
+               if (cdr.StatP & STATUS_SEEK) {
+                       SetPlaySeekRead(cdr.StatP, 0);
+                       cdr.DriveState = DRIVESTATE_STANDBY;
+               }
+               else {
+                       SetPlaySeekRead(cdr.StatP, STATUS_SEEK);
+                       CDRLID_INT(cdReadTime * 26);
+               }
                break;
        }
 }
@@ -440,27 +450,35 @@ static void generate_subq(const u8 *time)
        cdr.subq.Absolute[2] = itob(time[2]);
 }
 
-static void ReadTrack(const u8 *time) {
+static int ReadTrack(const u8 *time)
+{
        unsigned char tmp[3];
-       struct SubQ *subq;
-       u16 crc;
+       int read_ok;
 
        tmp[0] = itob(time[0]);
        tmp[1] = itob(time[1]);
        tmp[2] = itob(time[2]);
 
        if (memcmp(cdr.Prev, tmp, 3) == 0)
-               return;
+               return 1;
 
        CDR_LOG("ReadTrack *** %02x:%02x:%02x\n", tmp[0], tmp[1], tmp[2]);
 
-       cdr.NoErr = CDR_readTrack(tmp);
-       memcpy(cdr.Prev, tmp, 3);
+       read_ok = CDR_readTrack(tmp);
+       if (read_ok)
+               memcpy(cdr.Prev, tmp, 3);
+       return read_ok;
+}
+
+static void UpdateSubq(const u8 *time)
+{
+       const struct SubQ *subq;
+       u16 crc;
 
        if (CheckSBI(time))
                return;
 
-       subq = (struct SubQ *)CDR_getBufferSub();
+       subq = (struct SubQ *)CDR_getBufferSub(MSF2SECT(time[0], time[1], time[2]));
        if (subq != NULL && cdr.CurTrack == 1) {
                crc = calcCrc((u8 *)subq + 12, 10);
                if (crc == (((u16)subq->CRC[0] << 8) | subq->CRC[1])) {
@@ -470,8 +488,8 @@ static void ReadTrack(const u8 *time) {
                        memcpy(cdr.subq.Absolute, subq->AbsoluteAddress, 3);
                }
                else {
-                       CDR_LOG_I("subq bad crc @%02x:%02x:%02x\n",
-                               tmp[0], tmp[1], tmp[2]);
+                       CDR_LOG_I("subq bad crc @%02d:%02d:%02d\n",
+                               time[0], time[1], time[2]);
                }
        }
        else {
@@ -500,7 +518,7 @@ static void cdrPlayInterrupt_Autopause()
                //cdr.ResultReady = 1;
                //cdr.Stat = DataReady;
                cdr.Stat = DataEnd;
-               setIrq(0x200);
+               setIrq(0x1000); // 0x1000 just for logging purposes
 
                StopCdda();
                SetPlaySeekRead(cdr.StatP, 0);
@@ -539,13 +557,14 @@ static void cdrPlayInterrupt_Autopause()
                cdr.Stat = DataReady;
 
                SetResultSize(8);
-               setIrq(0x201);
+               setIrq(0x1001);
        }
 }
 
 static int cdrSeekTime(unsigned char *target)
 {
-       int seekTime = abs(msf2sec(cdr.SetSectorPlay) - msf2sec(target)) * (cdReadTime / 200);
+       int diff = msf2sec(cdr.SetSectorPlay) - msf2sec(target);
+       int seekTime = abs(diff) * (cdReadTime / 200);
        /*
        * Gameblabla :
        * It was originally set to 1000000 for Driver, however it is not high enough for Worms Pinball
@@ -566,31 +585,56 @@ static int cdrSeekTime(unsigned char *target)
        return seekTime;
 }
 
+static u32 cdrAlignTimingHack(u32 cycles)
+{
+       /*
+        * timing hack for T'ai Fu - Wrath of the Tiger:
+        * The game has a bug where it issues some cdc commands from a low priority
+        * vint handler, however there is a higher priority default bios handler
+        * that acks the vint irq and returns, so game's handler is not reached
+        * (see bios irq handler chains at e004 and the game's irq handling func
+        * at 80036810). For the game to work, vint has to arrive after the bios
+        * vint handler rejects some other irq (of which only cd and rcnt2 are
+        * active), but before the game's handler loop reads I_STAT. The time
+        * window for this is quite small (~1k cycles of so). Apparently this
+        * somehow happens naturally on the real hardware.
+        *
+        * Note: always enforcing this breaks other games like Crash PAL version
+        * (inputs get dropped because bios handler doesn't see interrupts).
+        */
+       u32 vint_rel;
+       if (psxRegs.cycle - rcnts[3].cycleStart > 250000)
+               return cycles;
+       vint_rel = rcnts[3].cycleStart + 63000 - psxRegs.cycle;
+       vint_rel += PSXCLK / 60;
+       while ((s32)(vint_rel - cycles) < 0)
+               vint_rel += PSXCLK / 60;
+       return vint_rel;
+}
+
+static void cdrUpdateTransferBuf(const u8 *buf);
 static void cdrReadInterrupt(void);
+static void cdrPrepCdda(s16 *buf, int samples);
+static void cdrAttenuate(s16 *buf, int samples, int stereo);
 
-void cdrPlaySeekReadInterrupt(void)
+static void msfiAdd(u8 *msfi, u32 count)
 {
-       if (cdr.Reading) {
-               cdrReadInterrupt();
-               return;
-       }
-
-       if (!cdr.Play && (cdr.StatP & STATUS_SEEK)) {
-               if (cdr.Stat) {
-                       CDR_LOG_I("cdrom: seek stat hack\n");
-                       CDRPLAYSEEKREAD_INT(0x1000, 1);
-                       return;
+       assert(count < 75);
+       msfi[2] += count;
+       if (msfi[2] >= 75) {
+               msfi[2] -= 75;
+               msfi[1]++;
+               if (msfi[1] == 60) {
+                       msfi[1] = 0;
+                       msfi[0]++;
                }
-               SetResultSize(1);
-               cdr.StatP |= STATUS_ROTATING;
-               SetPlaySeekRead(cdr.StatP, 0);
-               cdr.Result[0] = cdr.StatP;
-               cdr.Stat = Complete;
-               setIrq(0x202);
+       }
+}
 
-               Find_CurTrack(cdr.SetSectorPlay);
-               ReadTrack(cdr.SetSectorPlay);
-               cdr.TrackChanged = FALSE;
+void cdrPlayReadInterrupt(void)
+{
+       if (cdr.Reading) {
+               cdrReadInterrupt();
                return;
        }
 
@@ -613,44 +657,53 @@ void cdrPlaySeekReadInterrupt(void)
                cdrPlayInterrupt_Autopause();
 
        if (!cdr.Muted && !Config.Cdda) {
+               cdrPrepCdda(read_buf, CD_FRAMESIZE_RAW / 4);
                cdrAttenuate(read_buf, CD_FRAMESIZE_RAW / 4, 1);
                SPU_playCDDAchannel(read_buf, CD_FRAMESIZE_RAW, psxRegs.cycle, cdr.FirstSector);
                cdr.FirstSector = 0;
        }
 
-       cdr.SetSectorPlay[2]++;
-       if (cdr.SetSectorPlay[2] == 75) {
-               cdr.SetSectorPlay[2] = 0;
-               cdr.SetSectorPlay[1]++;
-               if (cdr.SetSectorPlay[1] == 60) {
-                       cdr.SetSectorPlay[1] = 0;
-                       cdr.SetSectorPlay[0]++;
-               }
-       }
+       msfiAdd(cdr.SetSectorPlay, 1);
 
        // update for CdlGetlocP/autopause
        generate_subq(cdr.SetSectorPlay);
 
-       CDRPLAYSEEKREAD_INT(cdReadTime, 0);
+       CDRPLAYREAD_INT(cdReadTime, 0);
 }
 
+#define CMD_PART2           0x100
+#define CMD_WHILE_NOT_READY 0x200
+
 void cdrInterrupt(void) {
-       int no_busy_error = 0;
        int start_rotating = 0;
        int error = 0;
-       unsigned int seekTime = 0;
+       u32 cycles, seekTime = 0;
        u32 second_resp_time = 0;
+       const void *buf;
        u8 ParamC;
        u8 set_loc[3];
+       int read_ok;
+       u16 not_ready = 0;
        u16 Cmd;
        int i;
 
        if (cdr.Stat) {
-               CDR_LOG_I("cdrom: cmd %02x with irqstat %x\n", cdr.CmdInProgress, cdr.Stat);
+               CDR_LOG_I("%u cdrom: cmd %02x with irqstat %x\n",
+                       psxRegs.cycle, cdr.CmdInProgress, cdr.Stat);
+               return;
+       }
+       if (cdr.Irq1Pending) {
+               // hand out the "newest" sector, according to nocash
+               cdrUpdateTransferBuf(CDR_getBuffer());
+               CDR_LOG_I("cdrom: %x:%02x:%02x loaded on ack\n",
+                       cdr.Transfer[0], cdr.Transfer[1], cdr.Transfer[2]);
+               SetResultSize(1);
+               cdr.Result[0] = cdr.Irq1Pending;
+               cdr.Stat = (cdr.Irq1Pending & STATUS_ERROR) ? DiskError : DataReady;
+               cdr.Irq1Pending = 0;
+               setIrq(0x1003);
                return;
        }
-
-       cdr.Ctrl &= ~0x80;
 
        // default response
        SetResultSize(1);
@@ -662,24 +715,44 @@ void cdrInterrupt(void) {
        ParamC = cdr.ParamC;
 
        if (Cmd < 0x100) {
-               cdr.Cmd = 0;
+               cdr.Ctrl &= ~0x80;
                cdr.ParamC = 0;
+               cdr.Cmd = 0;
+       }
+
+       switch (cdr.DriveState) {
+       case DRIVESTATE_PREPARE_CD:
+               if (Cmd > 2) {
+                       // Syphon filter 2 expects commands to work shortly after it sees
+                       // STATUS_ROTATING, so give up trying to emulate the startup seq
+                       cdr.DriveState = DRIVESTATE_STANDBY;
+                       cdr.StatP &= ~STATUS_SEEK;
+                       psxRegs.interrupt &= ~(1 << PSXINT_CDRLID);
+                       break;
+               }
+               // fallthrough
+       case DRIVESTATE_LID_OPEN:
+       case DRIVESTATE_RESCAN_CD:
+               // no disk or busy with the initial scan, allowed cmds are limited
+               not_ready = CMD_WHILE_NOT_READY;
+               break;
        }
 
-       switch (Cmd) {
+       switch (Cmd | not_ready) {
                case CdlNop:
+               case CdlNop + CMD_WHILE_NOT_READY:
                        if (cdr.DriveState != DRIVESTATE_LID_OPEN)
                                cdr.StatP &= ~STATUS_SHELLOPEN;
-                       no_busy_error = 1;
                        break;
 
                case CdlSetloc:
+               case CdlSetloc + CMD_WHILE_NOT_READY:
                        CDR_LOG("CDROM setloc command (%02X, %02X, %02X)\n", cdr.Param[0], cdr.Param[1], cdr.Param[2]);
 
                        // MM must be BCD, SS must be BCD and <0x60, FF must be BCD and <0x75
                        if (((cdr.Param[0] & 0x0F) > 0x09) || (cdr.Param[0] > 0x99) || ((cdr.Param[1] & 0x0F) > 0x09) || (cdr.Param[1] >= 0x60) || ((cdr.Param[2] & 0x0F) > 0x09) || (cdr.Param[2] >= 0x75))
                        {
-                               CDR_LOG("Invalid/out of range seek to %02X:%02X:%02X\n", cdr.Param[0], cdr.Param[1], cdr.Param[2]);
+                               CDR_LOG_I("Invalid/out of range seek to %02X:%02X:%02X\n", cdr.Param[0], cdr.Param[1], cdr.Param[2]);
                                error = ERROR_INVALIDARG;
                                goto set_error;
                        }
@@ -740,7 +813,9 @@ void cdrInterrupt(void) {
                        - plays tracks without retry play
                        */
                        Find_CurTrack(cdr.SetSectorPlay);
-                       ReadTrack(cdr.SetSectorPlay);
+                       generate_subq(cdr.SetSectorPlay);
+                       cdr.LocL[0] = LOCL_INVALID;
+                       cdr.SubqForwardSectors = 1;
                        cdr.TrackChanged = FALSE;
                        cdr.FirstSector = 1;
 
@@ -752,7 +827,7 @@ void cdrInterrupt(void) {
                        // BIOS player - set flag again
                        cdr.Play = TRUE;
 
-                       CDRPLAYSEEKREAD_INT(cdReadTime + seekTime, 1);
+                       CDRPLAYREAD_INT(cdReadTime + seekTime, 1);
                        start_rotating = 1;
                        break;
 
@@ -782,7 +857,7 @@ void cdrInterrupt(void) {
                        start_rotating = 1;
                        break;
 
-               case CdlStandby + 0x100:
+               case CdlStandby + CMD_PART2:
                        cdr.Stat = Complete;
                        break;
 
@@ -800,6 +875,7 @@ void cdrInterrupt(void) {
                        StopReading();
                        SetPlaySeekRead(cdr.StatP, 0);
                        cdr.StatP &= ~STATUS_ROTATING;
+                       cdr.LocL[0] = LOCL_INVALID;
 
                        second_resp_time = 0x800;
                        if (cdr.DriveState == DRIVESTATE_STANDBY)
@@ -808,7 +884,7 @@ void cdrInterrupt(void) {
                        cdr.DriveState = DRIVESTATE_STOPPED;
                        break;
 
-               case CdlStop + 0x100:
+               case CdlStop + CMD_PART2:
                        cdr.Stat = Complete;
                        break;
 
@@ -839,25 +915,26 @@ void cdrInterrupt(void) {
                                second_resp_time = (((cdr.Mode & MODE_SPEED) ? 2 : 1) * 1000000);
                        }
                        SetPlaySeekRead(cdr.StatP, 0);
-                       cdr.Ctrl |= 0x80;
                        break;
 
-               case CdlPause + 0x100:
+               case CdlPause + CMD_PART2:
                        cdr.Stat = Complete;
                        break;
 
                case CdlReset:
+               case CdlReset + CMD_WHILE_NOT_READY:
                        StopCdda();
                        StopReading();
                        SetPlaySeekRead(cdr.StatP, 0);
+                       cdr.LocL[0] = LOCL_INVALID;
                        cdr.Muted = FALSE;
                        cdr.Mode = 0x20; /* This fixes This is Football 2, Pooh's Party lockups */
-                       second_resp_time = 4100000;
-                       no_busy_error = 1;
+                       second_resp_time = not_ready ? 70000 : 4100000;
                        start_rotating = 1;
                        break;
 
-               case CdlReset + 0x100:
+               case CdlReset + CMD_PART2:
+               case CdlReset + CMD_PART2 + CMD_WHILE_NOT_READY:
                        cdr.Stat = Complete;
                        break;
 
@@ -875,24 +952,28 @@ void cdrInterrupt(void) {
                        break;
 
                case CdlSetmode:
+               case CdlSetmode + CMD_WHILE_NOT_READY:
                        CDR_LOG("cdrWrite1() Log: Setmode %x\n", cdr.Param[0]);
                        cdr.Mode = cdr.Param[0];
-                       no_busy_error = 1;
                        break;
 
                case CdlGetparam:
+               case CdlGetparam + CMD_WHILE_NOT_READY:
                        /* Gameblabla : According to mednafen, Result size should be 5 and done this way. */
                        SetResultSize(5);
                        cdr.Result[1] = cdr.Mode;
                        cdr.Result[2] = 0;
                        cdr.Result[3] = cdr.File;
                        cdr.Result[4] = cdr.Channel;
-                       no_busy_error = 1;
                        break;
 
                case CdlGetlocL:
+                       if (cdr.LocL[0] == LOCL_INVALID) {
+                               error = 0x80;
+                               goto set_error;
+                       }
                        SetResultSize(8);
-                       memcpy(cdr.Result, cdr.Transfer, 8);
+                       memcpy(cdr.Result, cdr.LocL, 8);
                        break;
 
                case CdlGetlocP:
@@ -906,7 +987,7 @@ void cdrInterrupt(void) {
                        start_rotating = 1;
                        break;
 
-               case CdlReadT + 0x100:
+               case CdlReadT + CMD_PART2:
                        cdr.Stat = Complete;
                        break;
 
@@ -943,7 +1024,7 @@ void cdrInterrupt(void) {
                case CdlSeekP:
                        StopCdda();
                        StopReading();
-                       SetPlaySeekRead(cdr.StatP, STATUS_SEEK);
+                       SetPlaySeekRead(cdr.StatP, STATUS_SEEK | STATUS_ROTATING);
 
                        seekTime = cdrSeekTime(cdr.SetSector);
                        memcpy(cdr.SetSectorPlay, cdr.SetSector, 4);
@@ -960,11 +1041,26 @@ void cdrInterrupt(void) {
                        Rockman X5 = 0.5-4x
                        - fix capcom logo
                        */
-                       CDRPLAYSEEKREAD_INT(cdReadTime + seekTime, 1);
+                       second_resp_time = cdReadTime + seekTime;
                        start_rotating = 1;
                        break;
 
+               case CdlSeekL + CMD_PART2:
+               case CdlSeekP + CMD_PART2:
+                       SetPlaySeekRead(cdr.StatP, 0);
+                       cdr.Result[0] = cdr.StatP;
+                       cdr.Stat = Complete;
+
+                       Find_CurTrack(cdr.SetSectorPlay);
+                       read_ok = ReadTrack(cdr.SetSectorPlay);
+                       if (read_ok && (buf = CDR_getBuffer()))
+                               memcpy(cdr.LocL, buf, 8);
+                       UpdateSubq(cdr.SetSectorPlay);
+                       cdr.TrackChanged = FALSE;
+                       break;
+
                case CdlTest:
+               case CdlTest + CMD_WHILE_NOT_READY:
                        switch (cdr.Param[0]) {
                                case 0x20: // System Controller ROM Version
                                        SetResultSize(4);
@@ -979,14 +1075,13 @@ void cdrInterrupt(void) {
                                        memcpy(cdr.Result, Test23, 4);
                                        break;
                        }
-                       no_busy_error = 1;
                        break;
 
                case CdlID:
                        second_resp_time = 20480;
                        break;
 
-               case CdlID + 0x100:
+               case CdlID + CMD_PART2:
                        SetResultSize(8);
                        cdr.Result[0] = cdr.StatP;
                        cdr.Result[1] = 0;
@@ -1011,6 +1106,7 @@ void cdrInterrupt(void) {
                        break;
 
                case CdlInit:
+               case CdlInit + CMD_WHILE_NOT_READY:
                        StopCdda();
                        StopReading();
                        SetPlaySeekRead(cdr.StatP, 0);
@@ -1018,27 +1114,30 @@ void cdrInterrupt(void) {
                        cdr.StatP |= STATUS_SHELLOPEN;
                        cdr.DriveState = DRIVESTATE_RESCAN_CD;
                        CDRLID_INT(20480);
-                       no_busy_error = 1;
                        start_rotating = 1;
                        break;
 
                case CdlGetQ:
-                       no_busy_error = 1;
+               case CdlGetQ + CMD_WHILE_NOT_READY:
                        break;
 
                case CdlReadToc:
+               case CdlReadToc + CMD_WHILE_NOT_READY:
+                       cdr.LocL[0] = LOCL_INVALID;
                        second_resp_time = cdReadTime * 180 / 4;
-                       no_busy_error = 1;
                        start_rotating = 1;
                        break;
 
-               case CdlReadToc + 0x100:
+               case CdlReadToc + CMD_PART2:
+               case CdlReadToc + CMD_PART2 + CMD_WHILE_NOT_READY:
                        cdr.Stat = Complete;
-                       no_busy_error = 1;
                        break;
 
                case CdlReadN:
                case CdlReadS:
+                       if (cdr.Reading && !cdr.SetlocPending)
+                               break;
+
                        Find_CurTrack(cdr.SetlocPending ? cdr.SetSector : cdr.SetSectorPlay);
 
                        if ((cdr.Mode & MODE_CDDA) && cdr.CurTrack > 1)
@@ -1056,23 +1155,30 @@ void cdrInterrupt(void) {
 
                        // Fighting Force 2 - update subq time immediately
                        // - fixes new game
-                       ReadTrack(cdr.SetSectorPlay);
+                       UpdateSubq(cdr.SetSectorPlay);
+                       cdr.LocL[0] = LOCL_INVALID;
+                       cdr.SubqForwardSectors = 1;
 
-                       CDRPLAYSEEKREAD_INT(((cdr.Mode & 0x80) ? (cdReadTime) : cdReadTime * 2) + seekTime, 1);
+                       cycles = (cdr.Mode & 0x80) ? cdReadTime : cdReadTime * 2;
+                       cycles += seekTime;
+                       if (Config.hacks.cdr_read_timing)
+                               cycles = cdrAlignTimingHack(cycles);
+                       CDRPLAYREAD_INT(cycles, 1);
 
                        SetPlaySeekRead(cdr.StatP, STATUS_SEEK);
                        start_rotating = 1;
                        break;
+
                case CdlSync:
                default:
-                       CDR_LOG_I("Invalid command: %02x\n", Cmd);
                        error = ERROR_INVALIDCMD;
                        // FALLTHROUGH
 
                set_error:
+                       CDR_LOG_I("cdrom: cmd %02x error %02x\n", Cmd, error);
                        SetResultSize(2);
                        cdr.Result[0] = cdr.StatP | STATUS_ERROR;
-                       cdr.Result[1] = error;
+                       cdr.Result[1] = not_ready ? ERROR_NOTREADY : error;
                        cdr.Stat = DiskError;
                        break;
        }
@@ -1082,26 +1188,14 @@ void cdrInterrupt(void) {
                cdr.StatP |= STATUS_ROTATING;
        }
 
-       if (!no_busy_error) {
-               switch (cdr.DriveState) {
-               case DRIVESTATE_LID_OPEN:
-               case DRIVESTATE_RESCAN_CD:
-               case DRIVESTATE_PREPARE_CD:
-                       SetResultSize(2);
-                       cdr.Result[0] = cdr.StatP | STATUS_ERROR;
-                       cdr.Result[1] = ERROR_NOTREADY;
-                       cdr.Stat = DiskError;
-                       break;
-               }
-       }
-
        if (second_resp_time) {
                cdr.CmdInProgress = Cmd | 0x100;
                CDR_INT(second_resp_time);
        }
        else if (cdr.Cmd && cdr.Cmd != (Cmd & 0xff)) {
                cdr.CmdInProgress = cdr.Cmd;
-               CDR_LOG_I("cdrom: cmd %02x came before %02x finished\n", cdr.Cmd, Cmd);
+               CDR_LOG_I("%u cdrom: cmd %02x came before %02x finished\n",
+                       psxRegs.cycle, cdr.Cmd, Cmd);
        }
 
        setIrq(Cmd);
@@ -1117,7 +1211,18 @@ void cdrInterrupt(void) {
  } while (0)
 #endif
 
-void cdrAttenuate(s16 *buf, int samples, int stereo)
+static void cdrPrepCdda(s16 *buf, int samples)
+{
+#if __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+       int i;
+       for (i = 0; i < samples; i++) {
+               buf[i * 2 + 0] = SWAP16(buf[i * 2 + 0]);
+               buf[i * 2 + 1] = SWAP16(buf[i * 2 + 1]);
+       }
+#endif
+}
+
+static void cdrAttenuate(s16 *buf, int samples, int stereo)
 {
        int i, l, r;
        int ll = cdr.AttenuatorLeftToLeft;
@@ -1167,7 +1272,7 @@ static void cdrReadInterruptSetResult(unsigned char result)
        SetResultSize(1);
        cdr.Result[0] = result;
        cdr.Stat = (result & STATUS_ERROR) ? DiskError : DataReady;
-       setIrq(0x203);
+       setIrq(0x1004);
 }
 
 static void cdrUpdateTransferBuf(const u8 *buf)
@@ -1184,21 +1289,33 @@ static void cdrUpdateTransferBuf(const u8 *buf)
 static void cdrReadInterrupt(void)
 {
        u8 *buf = NULL, *hdr;
+       u8 subqPos[3];
+       int read_ok;
+
+       memcpy(subqPos, cdr.SetSectorPlay, sizeof(subqPos));
+       msfiAdd(subqPos, cdr.SubqForwardSectors);
+       UpdateSubq(subqPos);
+       if (cdr.SubqForwardSectors < SUBQ_FORWARD_SECTORS) {
+               cdr.SubqForwardSectors++;
+               CDRPLAYREAD_INT((cdr.Mode & MODE_SPEED) ? (cdReadTime / 2) : cdReadTime, 0);
+               return;
+       }
 
+       // note: CdlGetlocL should work as soon as STATUS_READ is indicated
        SetPlaySeekRead(cdr.StatP, STATUS_READ | STATUS_ROTATING);
 
-       ReadTrack(cdr.SetSectorPlay);
-       if (cdr.NoErr)
+       read_ok = ReadTrack(cdr.SetSectorPlay);
+       if (read_ok)
                buf = CDR_getBuffer();
        if (buf == NULL)
-               cdr.NoErr = 0;
+               read_ok = 0;
 
-       if (!cdr.NoErr) {
+       if (!read_ok) {
                CDR_LOG_I("cdrReadInterrupt() Log: err\n");
-               memset(cdr.Transfer, 0, DATA_SIZE);
                cdrReadInterruptSetResult(cdr.StatP | STATUS_ERROR);
                return;
        }
+       memcpy(cdr.LocL, buf, 8);
 
        if (!cdr.Irq1Pending)
                cdrUpdateTransferBuf(buf);
@@ -1236,41 +1353,9 @@ static void cdrReadInterrupt(void)
        if (!(cdr.Mode & MODE_STRSND) || !(buf[4+2] & 0x4))
                cdrReadInterruptSetResult(cdr.StatP);
 
-       cdr.SetSectorPlay[2]++;
-       if (cdr.SetSectorPlay[2] == 75) {
-               cdr.SetSectorPlay[2] = 0;
-               cdr.SetSectorPlay[1]++;
-               if (cdr.SetSectorPlay[1] == 60) {
-                       cdr.SetSectorPlay[1] = 0;
-                       cdr.SetSectorPlay[0]++;
-               }
-       }
-
-       if (!cdr.Irq1Pending) {
-               // update for CdlGetlocP
-               ReadTrack(cdr.SetSectorPlay);
-       }
+       msfiAdd(cdr.SetSectorPlay, 1);
 
-       CDRPLAYSEEKREAD_INT((cdr.Mode & MODE_SPEED) ? (cdReadTime / 2) : cdReadTime, 0);
-}
-
-static void doMissedIrqs(void)
-{
-       if (cdr.Irq1Pending)
-       {
-               // hand out the "newest" sector, according to nocash
-               cdrUpdateTransferBuf(CDR_getBuffer());
-               CDR_LOG_I("cdrom: %x:%02x:%02x loaded on ack\n",
-                       cdr.Transfer[0], cdr.Transfer[1], cdr.Transfer[2]);
-               SetResultSize(1);
-               cdr.Result[0] = cdr.Irq1Pending;
-               cdr.Stat = (cdr.Irq1Pending & STATUS_ERROR) ? DiskError : DataReady;
-               cdr.Irq1Pending = 0;
-               setIrq(0x205);
-               return;
-       }
-       if (!(psxRegs.interrupt & (1 << PSXINT_CDR)) && cdr.CmdInProgress)
-               CDR_INT(256);
+       CDRPLAYREAD_INT((cdr.Mode & MODE_SPEED) ? (cdReadTime / 2) : cdReadTime, 0);
 }
 
 /*
@@ -1335,7 +1420,7 @@ void cdrWrite1(unsigned char rt) {
        }
 
 #ifdef CDR_LOG_CMD_IRQ
-       SysPrintf("CD1 write: %x (%s)", rt, CmdName[rt]);
+       SysPrintf("%u cdrom: CD1 write: %x (%s)", psxRegs.cycle, rt, CmdName[rt]);
        if (cdr.ParamC) {
                int i;
                SysPrintf(" Param[%d] = {", cdr.ParamC);
@@ -1356,8 +1441,8 @@ void cdrWrite1(unsigned char rt) {
                CDR_INT(5000);
        }
        else {
-               CDR_LOG_I("cdr: cmd while busy: %02x, prev %02x, busy %02x\n",
-                       rt, cdr.Cmd, cdr.CmdInProgress);
+               CDR_LOG_I("%u cdrom: cmd while busy: %02x, prev %02x, busy %02x\n",
+                       psxRegs.cycle, rt, cdr.Cmd, cdr.CmdInProgress);
                if (cdr.CmdInProgress < 0x100) // no pending 2nd response
                        cdr.CmdInProgress = rt;
        }
@@ -1366,7 +1451,7 @@ void cdrWrite1(unsigned char rt) {
 }
 
 unsigned char cdrRead2(void) {
-       unsigned char ret = 0;
+       unsigned char ret = cdr.Transfer[0x920];
 
        if (cdr.FifoOffset < cdr.FifoSize)
                ret = cdr.Transfer[cdr.FifoOffset++];
@@ -1388,7 +1473,7 @@ void cdrWrite2(unsigned char rt) {
                return;
        case 1:
                cdr.Reg2 = rt;
-               setIrq(0x204);
+               setIrq(0x1005);
                return;
        case 2:
                cdr.AttenuatorLeftToLeftT = rt;
@@ -1417,15 +1502,28 @@ void cdrWrite3(unsigned char rt) {
        case 0:
                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
-               if (cdr.Stat & rt)
-                       SysPrintf("ack %02x\n", cdr.Stat & 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, Shadow Tower (more) vs Discworld Noir (<993)
+                       if (!(psxRegs.interrupt & (1 << PSXINT_CDR)) &&
+                           (cdr.CmdInProgress || cdr.Irq1Pending))
+                       {
+                               s32 c = 2048 - (psxRegs.cycle - nextCycle);
+                               c = MAX_VALUE(c, 512);
+                               CDR_INT(c);
+                       }
+               }
                cdr.Stat &= ~rt;
 
                if (rt & 0x40)
                        cdr.ParamC = 0;
-               doMissedIrqs();
                return;
        case 2:
                cdr.AttenuatorLeftToRightT = rt;
@@ -1473,7 +1571,7 @@ void psxDma3(u32 madr, u32 bcr, u32 chcr) {
        switch (chcr & 0x71000000) {
                case 0x11000000:
                        ptr = (u8 *)PSXM(madr);
-                       if (ptr == NULL) {
+                       if (ptr == INVALID_PTR) {
                                CDR_LOG_I("psxDma3() Log: *** DMA 3 *** NULL Pointer!\n");
                                break;
                        }
@@ -1493,8 +1591,12 @@ void psxDma3(u32 madr, u32 bcr, u32 chcr) {
                        {
                                memcpy(ptr, cdr.Transfer + cdr.FifoOffset, size);
                                cdr.FifoOffset += size;
-                               psxCpu->Clear(madr, size / 4);
                        }
+                       if (size < cdsize) {
+                               CDR_LOG_I("cdrom: dma3 %d/%d\n", size, cdsize);
+                               memset(ptr + size, cdr.Transfer[0x920], cdsize - size);
+                       }
+                       psxCpu->Clear(madr, cdsize / 4);
 
                        CDRDMA_INT((cdsize/4) * 24);
 
@@ -1510,7 +1612,7 @@ void psxDma3(u32 madr, u32 bcr, u32 chcr) {
                        return;
 
                default:
-                       CDR_LOG("psxDma3() Log: Unknown cddma %x\n", chcr);
+                       CDR_LOG_I("psxDma3() Log: Unknown cddma %x\n", chcr);
                        break;
        }
 
@@ -1545,9 +1647,15 @@ void cdrReset() {
        cdr.Channel = 1;
        cdr.Reg2 = 0x1f;
        cdr.Stat = NoIntr;
-       cdr.DriveState = DRIVESTATE_STANDBY;
-       cdr.StatP = STATUS_ROTATING;
        cdr.FifoOffset = DATA_SIZE; // fifo empty
+       if (CdromId[0] == '\0') {
+               cdr.DriveState = DRIVESTATE_STOPPED;
+               cdr.StatP = 0;
+       }
+       else {
+               cdr.DriveState = DRIVESTATE_STANDBY;
+               cdr.StatP = STATUS_ROTATING;
+       }
        
        // BIOS player - default values
        cdr.AttenuatorLeftToLeft = 0x80;
@@ -1578,8 +1686,10 @@ int cdrFreeze(void *f, int Mode) {
        if (Mode == 0) {
                getCdInfo();
 
-               cdr.FifoOffset = tmp;
+               cdr.FifoOffset = tmp < DATA_SIZE ? tmp : DATA_SIZE;
                cdr.FifoSize = (cdr.Mode & 0x20) ? 2340 : 2048 + 12;
+               if (cdr.SubqForwardSectors > SUBQ_FORWARD_SECTORS)
+                       cdr.SubqForwardSectors = SUBQ_FORWARD_SECTORS;
 
                // read right sub data
                tmpp[0] = btoi(cdr.Prev[0]);
@@ -1596,7 +1706,7 @@ int cdrFreeze(void *f, int Mode) {
                        if (!Config.Cdda)
                                CDR_play(cdr.SetSectorPlay);
                        if (psxRegs.interrupt & (1 << PSXINT_CDRPLAY_OLD))
-                               CDRPLAYSEEKREAD_INT((cdr.Mode & 0x80) ? (cdReadTime / 2) : cdReadTime, 1);
+                               CDRPLAYREAD_INT((cdr.Mode & 0x80) ? (cdReadTime / 2) : cdReadTime, 1);
                }
 
                if ((cdr.freeze_ver & 0xffffff00) != 0x63647200) {