Boot system

■ System area

The system area is the first area on the CD-ROM.
System information and initial programs for starting applications are written in the system area.
These must be arranged continuously in the system area as IP (Initial Program).
The IP consists of the boot code and the application initials program (AIP). The boot code includes an ID such as the game name and a security code. The AIP contains the code for each initial program and so on.

Table 4.1 IP structure

structure			size	remarks
IP	BOOT CODE	SYSTEM ID	100H	Game name, product number, version, etc.
		SECURITY CODE	D00H	security code
		AREA CODE GROUP	20H-100H	Area code group
	APLICATION INITIAL PROGRAM		100H ~ 71E0H	Initial program, file system, etc.

(1000H-8000H in total)

■ SYSTEM ID

This is the first data to be placed in the system area.

Table 4.2 SYSTEM ID structure

0

1

2

3

4

5

6

7

8

9

A

B

C

D

E

F

00H

Hardware identifier

10H

Manufacturer ID

20H

Item Number

version

30H

Release date

Device information

40H

Corresponding area symbol

space

50H

Corresponding peripheral

60H

Game name

70H

80H

90H

A0H

B0H

C0H

D0H

RESERVED

E0H

IP SIZE

RESERVED

STACK-M

STACK-S

F0H

1st READ ADDRESS

1st READ SIZE

RESERVED

RESERVED

■ Explanation of SYSTEM ID (description principle)

● Available characters

All characters that can be used in the SYSTEM ID are ASCII code alphanumeric characters. However, depending on the item, the use of ". /-:" Is permitted.
In addition, all uppercase and lowercase letters can be used unless otherwise specified.

● Fill in

Fill in all left-justified unless instructed to do so. Do not put a space in front.
Unless otherwise instructed, fill all vacant parts with ASCII code 20H.

● Definition of expressions

The △ and space used in the explanation are ASCII code 20H.

● Other regulations

Be sure to fill the RESERVED area with 00H.

■ Explanation of each item

Hardware identifier (start address: 00H)

Definition

Enter a unique ID for your hardware

Available characters

Uppercase letters only

word count

16 characters

Entry rules

Be sure to enter "SEGA △ SEGA SATURN △".

Manufacturer ID (start address: 10H)

Definition

Enter the manufacturer ID specified by SEGA

Available characters

Alphanumeric characters only

word count

16 characters

Entry rules

For SEGA brands:

16 characters fixed for "SEGA △ ENTERPRISES"

For licensees:

16 characters of "SEGA △ TP △ KAIHA-A"

Enter the unique company code given to each licensee in KAISHA-A.

example)

SEGA △ TP △ T-999 △△△

Regulations:

Enter the manufacturer ID left-justified, and fill in the remainder with spaces to make sure it is 16 characters.

Item number (starting address: 20H)

Definition

Enter the item number specified by SEGA.

Available characters

Alphanumeric characters only

word count

10 characters

Entry rules

Fill the space with space.

Entry example

SEGA Brand Title: GS-9099 △△△
Licensee Title: T-99901G △△

Version (start address: 2AH)

Definition

Enter the application version.

Available characters

Uppercase "V", number, "." (Period)

word count

6 characters

Entry rules

Always start with a "V", then a one-digit number, then a ".", And then a three-digit number.
The final release will be V1.000.

Entry example

For sample disc → V0.801
For master disk → V1.000

Release date (start address: 30H)

Definition

Enter the date when the master disc (write once disc) was created.

Available characters

Numbers only

word count

8 characters

Entry rules

Make sure that the year is 4 digits and the month and day are 2 digits.

Entry example

19940912 (for September 12, 1994)

Device information (start address: 38H)

Definition

Fill in the device information. In the case of a CD, enter the number of the set.

Available characters

Alphanumeric characters and "/-"

word count

8 characters

Entry rules

Fill the space with space.

Entry example

1 CD set, 1st CD → CD-1 / 1 △△
Set of 3 CDs, 2nd CD → CD-2 / 3 △△

Corresponding area symbol (start address: 40H)

Definition

Enter the area symbol of the area where you want the application to work.

Available characters

Only uppercase letters specified in the area symbol list below

word count

10 characters

Entry rules

Multiple entries are possible. Fill in the area symbols and area symbols together, with no spaces or commas in between. Fill the space with space.

Area symbol list

J → Japan
T → Asia NTSC (Taiwan, Philippines, South Korea)
U → North America (US, Canada), Latin America NTSC (Brazil)
E → Europe PAL, East Asia PAL, Latin America PAL

Entry example

For applications that run in Japan, Taiwan, and South Korea (does not work in other regions) → JTK △△△△△△△

caution

It is necessary to put the area code corresponding to the area entered here in the area code group. (See 4.5 Area Codes)

supplementary explanation

Hardware has information "area symbols" that differ depending on the sales area. The application starts when the "area symbol", the "area symbol in the corresponding area symbol", and the "area code" match.

Corresponding peripheral (start address: 50H)

Definition

Fully compatible Input Fill in peripheral information.

Available characters

Only alphanumeric characters specified in the character list below

word count

16 characters

Entry rules

Multiple entries are possible. The order of the characters does not matter.
Fill in the characters and characters together, with no spaces or commas in between. Fill the space with space.

Character list

A → Mission stick
C → Battle cable
D → Modem (or Net Link)
E → Multi controller
F → FDD
G → Gun (Virtual Gun)
J → Sega Saturn standard pad
K → keyboard
M → Shuttle mouse
P → MPEG
R → Data cartridge (twin advanced system)
S → Steering controller
T → Multi Terminal 6
W → Expansion ram cartridge
X → XBAND

Entry example

For applications that support standard joypads and mice
JM △△△△△△△△△△△△△△

supplement

The number of peripherals will increase and the number of characters will increase in the future.
For the definition of full support, refer to the pad check item in "Software Creation Standards".

Game name (start address: 60H)

Definition

Enter the game name.

Available characters

The game name is alphanumeric only. Spaces can be used in the game name.
When listing multiple titles, "/-:" can be used as the delimiter between titles.

word count

112 characters.

Entry rules

If the name is different depending on the sales area, you may list multiple titles. There are no detailed rules for entering multiple entries, but enter them so that the title can be identified by looking at this part. Fill the empty space with space.

Entry example

When there are multiple titles

Example 1)

TITLE1 / TITLE2 / TITLE3 △△△△

Example 2)

J: TITLE1 △△ U: TITLE2 △△△△△△

IP SIZE (starting address: E0H)

Definition

Specify the size (number of bytes) of IP (Initial Program).

size

4 bytes

Regulations

Add AIP just after the boot code to make one file and specify the size of that file.
The parameter must be a longword boundary (a multiple of 4H).

range

1000H ~ 8000H

STACK-M (start address: E8H)

Definition

Master-SH2 stack pointer address.
By default (specify 0), 6001000H to 6001FFFH is the stack area.

size

4 bytes

Regulations

The parameter must be a longword boundary (a multiple of 4H).

range

600B000H ~ 6100000H

STACK-S (start address: ECH)

Definition

Slave-SH2 stack pointer address.
By default (specify 0), 6000E00H to 6000FFFH is the stack area.

size

4 bytes

Regulations

The parameter must be a longword boundary (a multiple of 4H).

range

600A200H ~ 6100000H

1st READ ADDRESS (start address: F0H)

Definition

Forwarding address of the look-ahead file (1st READ FILE).
A look-ahead file is a file that the boot system transfers to WORKRAM while the License Sega logo is displayed.

size

4 bytes

Regulations

In the case of 0H, no transfer is performed.
When transferring, if it is a CD, transfer the file with the file identifier [2]. The parameter must be a longword boundary (a multiple of 4H).

range

200,000H to 300,000H
(6002000H + IPSIZE) ~ 6100000H

supplement

Refer to the section "4.7 Look-ahead files and application initial programs" The look-ahead file must be on the MODE1 track. Also, it must be track 1.
The file with the file identifier [2] is the first file in the root directory. If the file name is set to "1ST.BIN" etc., it will be sorted and will be at the beginning.

1st READ SIZE (start address: F4H)

Definition

Ignored for CDs.

size

4 bytes

Regulations

The parameter must be (a multiple of 4H) at the longword boundary.

■ Security code

Place it immediately after the SYSTEM ID. The code is provided by SEGA as an object code, so please use it as it is without making any changes. The contents are the program and data that displays the SEGA license. Applications that do not have the correct security code will not be recognized as a Sega Saturn CD and will not be able to launch the game.
Security code provided file name: Software library In the directory after disk installation

\ SATURN \ SEGALIB \ LIB \ SYS_SEC.OBJ
                    ~~~~~~~~~~~

■ Area code

Place it just behind the security code. The code is provided by SEGA as an object code, so please use it as it is without making any changes.
There are four types of area codes for each hardware sales area, but it is necessary to enter the area code corresponding to the "corresponding area symbol" of the SYSTEM ID. When listing more than one, make sure that the "corresponding area symbol" and "area code" are entered in the same order.
The size of each area code is the same, so it can be easily changed.
Also, by connecting multiple area codes, it is possible to make a common disc. ( Refer to "Appendix A Various Sample Lists ") Area code provided File name: In the directory after installing the software library disk

\ SATURN \ SEGALIB \ LIB \ SYS_ARE? .OBJ ;? Is the same character as the corresponding area ~~~~~~~~~~~~; There are 4 types

Table 4.3 shows the relationship between the hardware sales area, area code, and corresponding area symbol.

Table 4.3 Relationship between area code and area symbol

Correspondence area	Hardware sales area	Area code file name
J	Japan	SYS_AREJ.OBJ
T	Asia NTSC region	SYS_ARET.OBJ
U	North America, Latin America NTSC region	SYS_AREU.OBJ
E	Europe PAL, East Asia PAL, Latin America PAL	SYS_AREE.OBJ

■ Application initial program

By placing it immediately after the area code group, it will be executed immediately after the area code is executed. After that, the program proceeds under the control of the application.

■ Look-ahead file and application initial program

Both are systems in which BOOT ROM automatically transfers files from a CD-ROM. By using this, the specified file can be transferred at startup without the application programming.

■ 1st READ FILE

The file (file identifier is [2]) read by the boot system while the license SEGA logo is displayed (security code is being executed) is called the 1st READ FILE (look-ahead file). The license SEGA logo display does not end until this 1st READ FILE has been read. Therefore, the larger the size of the transfer file, the longer the license SEGA logo screen will take. (Minimum 2 seconds, maximum about 3.5 seconds)
If 1st READ ADDRESS is set, the 1st READ FILE will only be read and will not be executed automatically.
It is possible not to specify it, but it is recommended to use it because the time when the license SEGA logo is displayed can be used effectively.

■ Application initial program

For example, by placing a file system in this program, subsequent access to the CD can be easily performed on a file-by-file basis.
By making good use of both, it is possible to create efficient applications.

Figure 4.1 Concept from power-on

TV screen: BOOT-ROM ~ Application startup　
:　
: (Power input)　
: ┌──────┴──────┐　
: │ │　
┌────────────┐┌──────┴─────┐┌──────┴──────┐　
│ │ │ │ │ SYSTEM ID check │　
│ │ │ │ │ │ │ │　
│ │ │ │ │ Security code check │　
│ SEGA SATURN logo │ │ SEGA SATURN logo │ │ │ │ │　
│ │ │ Display processing │ │ Area code check │　
│ │ │ │ │ │ │ │　
│ │ │ │ │ IP load ┌──┴─────────┐
└──────┬─────┘└──────┬─────┘└──────┬───┤ AIP is loaded │
│ │ │ └────────────┘
┌──────┴─────┐┌──────┴─────┐┌──────┴────────────── ┐
│ │ │ │ │ │ │
│ │ │ Security code execution │ │ │
│ │ │ │ │ │ Read the file with the file identifier [2], │
│ License Sega logo │ │ Area code execution │ │ SYSTEM ID │ │
│ │ │ │ │ │ 1st READ ADDRESS │
│ │ │ System initialization code execution │ │ Transfer to the transfer destination written in │ │
│ │ │ (SYS_INIT) │ │ │
└──────┬─────┘└──────┬─────┘└──────┬────────────── ┘
│ │ │　
┌──────┴─────┐┌──────┴─────────────┴─────┐　
│ │ │ Application initial program (AIP) execution │　
│ │ │ (SMPSYSC, etc.) │　
│ │ └──────┬─────────────┬─────┘　
│ Application │ │ │ │　
│ │ ┌──────┴─────────────┴─────┐　
│ │ │ Execute the application program itself │　
│ │ │ (1st READ file) │　
└────────────┘└───────────────────────────┘　

■ How to create an IP

● SYS_ID.SRC

This is a sample assembler source program for creating a SYSTEM ID. Please change according to the application. (See "4.3 SYSTEM ID Description")
Be sure to put it at the beginning of the program.

File name provided by the above sample: In the directory after installing the software library disk

\ SATURN \ SEGASMP \ SYS \ SYS_ID.SRC

● SYS_SEC.OBJ

Security code object. ( Refer to "■ Security Code ") Link and incorporate as it is.

● SYS_ARE? .OBJ

Area code object. ( Refer to "■ Area Code ") Link and incorporate as it is.

● SYS_INIT.OBJ

An object of system initialization code. Link and incorporate as it is.

The above files

SYS_ID.OBJ, SYS_SEC.OBJ, SYS_ARE? .OBJ, SYS_INIT.OBJ, ...

Create SYS_IP.BIN by linking in the order of. Place this file in the system area of the CD.

■ IP placement

The IP size can be created in the range of a minimum of 2 sectors and a maximum of 16 sectors.
If the required IP size is 8 sectors or less, it is possible to record multiple IPs to improve reliability. At this time, place each IP from the beginning of the sector.
This will increase the chances of booting even if the first sector has a read failure.