13. Backup library

Sega Saturn has a built-in buffer memory of 32 kbytes. This chapter describes the backup library for using this built-in buffer memory.
The main body of the backup library is compressed and stored in the Sega Saturn B00TROM. You can use this backup library to exchange data with buffer memory and external cartridges.

13-1. Features of backup library

device

● Supported devices

Devices such as internal backup memory and external cartridges (currently these two types) can be accessed in a file format that does not have a hierarchical structure (Table 13-1). In addition, these devices are partitioned by partition as shown in Figure 13-1.

● Connection information (Config) for each device

The connection information (Config) of each device can be obtained at the initial of the backup library.

● Information for each device (Status: connected / disconnected, formatted / unformatted, etc.)

It can be obtained using the backup library function. You can also specify the size of the file you want to write and check if it is writable.

Table 13-1 Device list

Device number	Device type
0	Built-in memory cartridge
1	Memory cartridge or parallel interface

Figure 13-1 Device configuration

File

Information (Dir: name, creation time, etc.) for each file can be obtained in the same way using the backup library function.
The file information setting at the time of file creation is the responsibility of the user at the time of file creation, and the backup library itself does not create the file information.

Library expansion

The main body of the backup library is compressed and stored in the Sega Saturn BOOTROM. When the user uses the backup library, the program expansion area and work area are secured and the initial processing is performed. After that, each function can be used.

caution	The backup library destroys data if processing is interrupted while writing data. Therefore, when initializing, formatting, writing, or deleting the backup library, use “slResetDisable ()” (peripheral function) in the system library to disable the reset button.

13-2. Basic processing flow

The backup library function is explained along with the basic processing flow.

1) Initialization [BUP_Init ()]

Reads the backup library from BOOTROM and expands it to the specified address space. Returns each device information at that time.

2) Select partition [BUP_SelPart ()]

Specify the partition of the device to be used. The default partition is number 0 (internal memory cartridge).

3) Get status [BUP_Stat ()]

Get the status of the device you want to read and write. When writing, specify the size of the data you want to write in bytes. You can tell whether it is writable by the return value.

4) Format [BUP_Format ()]

If the device you want to use is unformatted due to the status acquisition, you need to format it. The format range is the specified partition of the specified device.

5) Get directory information [BUP_Dir ()]

Get the directory information by specifying the file name (or for all files). If you want information about all files, specify NULL for the file name.

6) Write data [BUP_Write ()]

Specify the device and write the file. The file information required at that time is created by the user.

7) Data query [BUP_Verify ()]

Specify the device and inquire about the written file.

8) Read data [BUP_Read ()]

Specify the device to read the file.

9) Delete data [BUP_Delete ()]

Specify the device and delete the file.

10) Expansion of date data [BUP_GetDate ()]

Compresses into file information and expands the stored date data.

11) Compression of date data [BUP_SetDate ()]

Compress to store date data in file information.

13-3. Sample program

Next, the flow chart of the sample program that uses the backup library is shown.

Flow 13-1 Sample program that uses the backup library

Listing 13-1 shows the program list of the sample program.

Listing 13-1 Sample program

---

#include "sgl.h"
#define BUP_START_ADDR 0x6070000
#include "sega_bup.h"

#define FILE_NAME "FILE_NAME01"
#define BACKUP_DEVICE (Uint32) 0
#define TEST_DATA "It's a pen"
#define TEST_SIZE 10
#define DIR_SIZE 8
#define HEX2DEC (x) ((0x0f & (x)) + ((x) >> 4) * 10)

/ ***************************************************** ** **

  sample for backupram

****************************************************** * /

Uint32 BackUpRamWork [2048 + 30];

void BackUpInit (BupConfig cntb [3])
{
	slResetDisable ();
	BUP_Init ((Uint32 *) BUP_START_ADDR, BackUpRamWork, cntb);
	slResetEnable ();
}

Sint32 BackUpWrite (Uint32 device, BupDir * dir, Uint8 * data, Uint8 sw)
{
	Sint32 ret;
	SmpcDateTime * time;
	BupDate date;
	
	if (! dir-> date) {
		time = & (Smpc_Status-> rtc);
		date.year = (Uint8) (slDec2Hex ((Uint32) time-> year)-1980); / * Modify KT * /
		date.month = (Uint8) (time-> month & 0x0f);
		date.week = (Uint8) (time-> month >> 4);
		date.day = (Uint8) (slDec2Hex ((Uint32) time-> date)); / * Modify KT * /
		date.time = (Uint8) (slDec2Hex ((Uint32) time-> hour)); / * Modify KT * /
		date.min = (Uint8) (slDec2Hex ((Uint32) time-> minute)); / * Modify KT * /
		dir-> date = BUP_SetDate (& date);
	}
	slResetDisable ();
	ret = BUP_Write (device, dir, data, sw);
	slResetEnable ();

	return (ret);
}

Sint32 BackUpDelete (Uint32 device, Uint8 * filename)
{
	Sint32 ret;

	slResetDisable ();
	ret = BUP_Delete (device, filename);
	slResetEnable ();

	return (ret);
}


Sint32 BackUpFormat (Uint32 device)
{
	Sint32 ret;

	slResetDisable ();
	ret = BUP_Format (device);
	slResetEnable ();

	return (ret);
}


void ss_main ()
{
    BupConfig conf [3];
    BupStat sttb;
    BupDir dir, dirs [DIR_SIZE];
    BupDate datetb, date;
    Uint8 * time;
    Sint32 status;
    Uint8 buf [256];
    int i, lin = 4;

    slInitSystem (TV_352x224, (TEXTURE *) NULL, 1);

    slPrint ("Sample program Backup Library", slLocate (9,2));

    slGetStatus (); 
    for (i = 0; i <100; i ++)
      {
	  slSynch ();
      }

    BackUpInit (conf);
                                                
    if ((status = BUP_Stat (BACKUP_DEVICE, 10, & sttb)) == BUP_UNFORMAT)
      {
	  status = BackUpFormat (BACKUP_DEVICE);
	  slPrint ("Formatting device", slLocate (10, lin));
	  BUP_Stat (BACKUP_DEVICE, TEST_SIZE, & sttb);
      }

    if (sttb.freeblock> 0)
      {
	  strncpy (dir.filename, FILE_NAME, 11);
	  strncpy (dir.comment, "Test desu", 10);
	  dir.language = BUP_ENGLISH;
	  dir.datasize = TEST_SIZE;
	  dir.date = 0;
 	  slPrint ("Writing file.", SlLocate (10, ++ lin));
	  slPrint ("Filename =", slLocate (13, ++ lin));
	  slPrint (FILE_NAME, slLocate (23, lin));
	  status = BackUpWrite (BACKUP_DEVICE, & dir, (Uint8 *) TEST_DATA, OFF);
	  status = BUP_Verify (BACKUP_DEVICE, (Uint8 *) FILE_NAME, (Uint8 *) TEST_DATA);
      }

    status = BUP_Dir (BACKUP_DEVICE, (Uint8 *) FILE_NAME, DIR_SIZE, dirs);
    status = BUP_Dir (BACKUP_DEVICE, (Uint8 *) "", DIR_SIZE, dirs);
    for (i = 0; i <status && i <10; i ++)
      {
	  char cmnt [11] = "Dirs =";

	  cmnt [6] = (char) (i + 20);
	  slPrint ("Dirs =", slLocate (10, ++ lin));
	  slPrint (dirs [i] .filename, slLocate (20, lin));
      }
    status = BackUpWrite (BACKUP_DEVICE, & dir, (Uint8 *) TEST_DATA, OFF);
    status = BUP_Read (BACKUP_DEVICE, (Uint8 *) FILE_NAME, buf);
    slPrint ("Reading file.", SlLocate (10, ++ lin));
    slPrint ("Filename =", slLocate (13, ++ lin));
    slPrint (FILE_NAME, slLocate (23, lin));
#if 0
    status = BackUpDelete (BACKUP_DEVICE, (Uint8 *) FILE_NAME);
    status = BUP_Dir (BACKUP_DEVICE, (Uint8 *) "", DIR_SIZE, dirs);
    slPrint ("Deleting =", slLocate (10, ++ lin));
    slPrint ("Filename =", slLocate (13, ++ lin));
    slPrint (FILE_NAME, slLocate (23, lin));
#endif
    for (i = 0; i <status && i <10; i ++)
      {
	  char cmnt [11] = "Dirs =";

	  cmnt [6] = (char) (i + 20);
	  slPrint ("Dirs =", slLocate (10, ++ lin));
	  slPrint (dirs [i] .filename, slLocate (20, lin));
      }

    for (;;)
      {
	  slSynch ();
      }
}

---

Appendix Backup library function

Table 13-2 lists the functions used by the backup library.
For a detailed reference of the function, refer to PROGRAMMER'S GUIDE VOL.1.

Table 13-2 Backup library functions

number	Seki several people	function
1	BUP_Init	Backup library initialization
2	BUP_SelPart	Partition selection
3	BUP_Format	Formatting
Four	BUP_Stat	Get status
Five	BUP_Write	Writing data
6	BUP_Read	Read data
7	BUP_Delete	Delete data
8	BUP_Dir	Get directory information
9	BUP_Verify	Display data
Ten	BUP_GetDate	Deployment of date data
11	BUP_SetDate	Compression of date data