Fixed CD-ROM timings on the NCR 53x8xx SCSI controllers, the IDE_TIME, CDROM_TIME, and ZIP_TIME values, and the delay added to the CD-ROM READ SUBCHANNEL command, fixes slowdowns on several games that use CD Audio, such as Tomb Raider II.

src/scsi/scsi_cdrom.c

@@ -9,7 +9,7 @@
  *		Implementation of the CD-ROM drive with SCSI(-like)
  *		commands, for both ATAPI and SCSI usage.
  *
- * Version:	@(#)scsi_cdrom.c	1.0.71	2019/09/26
+ * Version:	@(#)scsi_cdrom.c	1.0.72	2019/11/19
  *
  * Author:	Miran Grca, <mgrca8@gmail.com>
  *
@@ -604,15 +604,19 @@ scsi_cdrom_update_request_length(scsi_cdrom_t *dev, int len, int block_len)
 static double
 scsi_cdrom_bus_speed(scsi_cdrom_t *dev)
 {
+    double ret = -1.0;
+
     if (dev->drv->bus_type == CDROM_BUS_SCSI) {
 	dev->callback = -1.0;	/* Speed depends on SCSI controller */
 	return 0.0;
     } else {
-	/* TODO: Get the actual selected speed from IDE. */
-	if (scsi_cdrom_current_mode(dev) == 2)
-		return 66666666.666666666666666;	/* 66 MB/s MDMA-2 speed */
-	else
-		return  8333333.333333333333333;	/* 8.3 MB/s PIO-2 speed */
+	if (dev && dev->drv)
+		ret = ide_atapi_get_period(dev->drv->ide_channel);
+	if (ret == -1.0) {
+		dev->callback = -1.0;
+		return 0.0;
+	} else
+		return ret * 1000000.0;
     }
 }
 
@@ -663,7 +667,7 @@ scsi_cdrom_command_common(scsi_cdrom_t *dev)
 		case 0xb9:
 		case 0xbe:
 			if (dev->current_cdb[0] == 0x42)
-				dev->callback += 200.0 * CDROM_TIME;
+				dev->callback += 40.0;
 			/* Account for seek time. */
 			bytes_per_second = 176.0 * 1024.0;
 			bytes_per_second *= (double) dev->drv->cur_speed;

src/scsi/scsi_cdrom.h

@@ -9,17 +9,17 @@
  *		Implementation of the CD-ROM drive with SCSI(-like)
  *		commands, for both ATAPI and SCSI usage.
  *
- * Version:	@(#)scsi_cdrom.h	1.0.1	2018/10/17
+ * Version:	@(#)scsi_cdrom.h	1.0.2	2019/11/19
  *
  * Author:	Miran Grca, <mgrca8@gmail.com>
  *
- *		Copyright 2018 Miran Grca.
+ *		Copyright 2018,2019 Miran Grca.
  */
 #ifndef EMU_SCSI_CDROM_H
 #define EMU_SCSI_CDROM_H
 
 
-#define CDROM_TIME	500.0
+#define CDROM_TIME	10.0
 
 
 #ifdef SCSI_DEVICE_H

src/scsi/scsi_ncr53c8xx.c

@@ -13,7 +13,7 @@
  *		To do: Identify the type of serial EEPROM used and its
  *		interface.
  *
- * Version:	@(#)scsi_ncr53c8xx.c	1.0.17	2018/10/30
+ * Version:	@(#)scsi_ncr53c8xx.c	1.0.18	2019/11/19
  *
  * Authors:	Paul Brook (QEMU)
  *		Artyom Tarasenko (QEMU)
@@ -705,10 +705,12 @@ ncr53c8xx_add_msg_byte(ncr53c8xx_t *dev, uint8_t data)
 static void
 ncr53c8xx_timer_on(ncr53c8xx_t *dev, scsi_device_t *sd, double p)
 {
-    if (p <= 0)
-	timer_on_auto(&dev->timer, ((double) sd->buffer_length) * 0.1);	/* Fast SCSI: 10000000 bytes per second */
-    else
-	timer_on_auto(&dev->timer, p);
+    double period;
+
+    /* Fast SCSI: 10000000 bytes per second */
+    period = (p > 0.0) ? p : (((double) sd->buffer_length) * 0.1);
+
+    timer_on_auto(&dev->timer, period + 40.0);
 }
 
 
@@ -1023,11 +1025,12 @@ again:
 	/* If we receive an empty opcode increment the DSP by 4 bytes
 	   instead of 8 and execute the next opcode at that location */
 	dev->dsp += 4;
-	timer_on_auto(&dev->timer, 10.0);
 	if (insn_processed < 100)
 		goto again;
-	else
+	else {
+		timer_on_auto(&dev->timer, 10.0);
 		return;
+	}
     }
     addr = read_dword(dev, dev->dsp + 4);
     ncr53c8xx_log("SCRIPTS dsp=%08x opcode %08x arg %08x\n", dev->dsp, insn, addr);
@@ -1093,8 +1096,6 @@ again:
 				dev->dfifo = dev->dbc & 0xff;
 				dev->ctest5 = (dev->ctest5 & 0xfc) | ((dev->dbc >> 8) & 3);
 
-				timer_on_auto(&dev->timer, 40.0);
-
 				if (dev->dcntl & NCR_DCNTL_SSM)
 					ncr53c8xx_script_dma_interrupt(dev, NCR_DSTAT_SSI);
 				return;
@@ -1363,8 +1364,6 @@ again:
 		ncr53c8xx_log("%02X: Unknown command\n", (uint8_t) (insn >> 30));
     }
 
-    timer_on_auto(&dev->timer, 40.0);
-
     ncr53c8xx_log("instructions processed %i\n", insn_processed);
     if (insn_processed > 10000 && !dev->waiting) {
 	/* Some windows drivers make the device spin waiting for a memory
@@ -1393,6 +1392,8 @@ again:
 		ncr53c8xx_log("NCR 810: SCRIPTS: Waiting\n");
     }
 
+    timer_on_auto(&dev->timer, 40.0);
+
     ncr53c8xx_log("SCRIPTS execution stopped\n");
 }
 
@@ -1419,8 +1420,6 @@ ncr53c8xx_callback(void *p)
 
     if (dev->sstop)
 	timer_stop(&dev->timer);
-    else
-	timer_on_auto(&dev->timer, 10.0);
 }