File Formats
Key:
EOR - Bitwise Exclusive OR, 0x0000 - Hex Number, %00000000 - Binary Number
BBC Micro
| Offset into file | Content | Size | Format |
| 0x0000 | Password Data | 8 bytes per screen, 8 screens | Each letter is [byte] EOR (63-offset). Terminated by CR (ASCII 13) |
| 0x0040 | Time Limits | 2 bytes per screen, 8 screens | [byte1] + [byte2] * 256 (i.e. First byte is LSB, second byte is MSB) |
| 0x0050 | Edit Codes | 2 bytes per screen, 8 screens | [byte1] + [byte2] * 256 (i.e. First byte is LSB, second byte is MSB) |
| 0x0060 | Transporters | 4 bytes per transporter, 4 transporters per screen, 8 screens. | Source x,y , Destination x,y. If no transporters, first byte is 0xFF |
| 0x00E0 | Colour Palette | 4 bytes per screen, 8 screens. | Each byte represents a BBC Colour (i.e. 0:Black, 1:Red, 2:Green, 3:Yellow, 4:Blue, 5:Magenta, 6:Cyan, 7:White) |
| 0x0100 | Map Data | 420 bytes per screen, 8 screens | The map is represented by a number which indicates which character (0-47). Each 8 characters are packed into 5 bytes, across map then down (28x24 characters): Chr 1 bits 0-4 are Byte 1 bits 0-4 Chr 2 bits 0-2 are Byte 1 bits 5-7 Chr 2 bits 3-4 are Byte 2 bits 0-1 Chr 3 bits 0-4 are Byte 2 bits 2-6 Chr 4 bit 0 is Byte 2 bit 7 Chr 4 bits 1-4 are Byte 3 bits 0-3 Chr 5 bits 0-3 are Byte 3 bits 4-7 Chr 5 bit 4 is Byte 4 bit 0 Chr 6 bits 0-4 are Byte 4 bits 1-5 Chr 7 bits 0-1 are Byte 4 bits 6-7 Chr 7 bits 2-4 are Byte 5 bits 0-2 Chr 8 bits 0-4 are Byte 5 bits 3-7 |
| 0x0E20 | Character Data | 128 bytes per character, 48 characters | Each byte represents four pixels per character, across character then down (16x32): %12341234 for pixels 1,2,3 and 4 (2 bits each) representing one of four colours (0,1,2 or 3) |
| Total file size: 9760 bytes |
Acorn Electron
| Offset into file | Content | Size | Format |
| 0x0000 | Password Data | 8 bytes per screen, 8 screens | Each letter is [byte] EOR (63-offset). Terminated by CR (ASCII 13) |
| 0x0040 | Time Limits | 2 bytes per screen, 8 screens | [byte1] + [byte2] * 256 (i.e. First byte is LSB, second byte is MSB) |
| 0x0050 | Edit Codes | 2 bytes per screen, 8 screens | [byte1] + [byte2] * 256 (i.e. First byte is LSB, second byte is MSB) |
| 0x0060 | Transporters | 4 bytes per transporter, 4 transporters per screen, 8 screens. | Source x,y , Destination x,y. If no transporters, first byte is 0xFF |
| 0x00E0 | Colour Palette | 4 bytes per screen, 8 screens. | Each byte represents a BBC Colour (i.e. 0:Black, 1:Red, 2:Green, 3:Yellow, 4:Blue, 5:Magenta, 6:Cyan, 7:White) |
| 0x0100 | Map Data | 420 bytes per screen, 8 screens | The map is represented by a number which indicates which character (0-47). Each 8 characters are packed into 5 bytes, across map then down (28x24 characters): Chr 1 bits 0-4 are Byte 1 bits 0-4 Chr 2 bits 0-2 are Byte 1 bits 5-7 Chr 2 bits 3-4 are Byte 2 bits 0-1 Chr 3 bits 0-4 are Byte 2 bits 2-6 Chr 4 bit 0 is Byte 2 bit 7 Chr 4 bits 1-4 are Byte 3 bits 0-3 Chr 5 bits 0-3 are Byte 3 bits 4-7 Chr 5 bit 4 is Byte 4 bit 0 Chr 6 bits 0-4 are Byte 4 bits 1-5 Chr 7 bits 0-1 are Byte 4 bits 6-7 Chr 7 bits 2-4 are Byte 5 bits 0-2 Chr 8 bits 0-4 are Byte 5 bits 3-7 |
| 0x0E20 | Character Data | 72 bytes per character, 48 characters | Each byte represents four pixels per character, across character then down (12x24): %12341234 for pixels 1,2,3 and 4 (2 bits each) representing one of four colours (0,1,2 or 3) |
| 0x1BA0 | Unused | 640 bytes | Undefined |
| Total file size: 7712 bytes |
Commodore 64
| Offset into file | Content | Size | Format |
| 0x0000 | Unknown | 2 bytes | Should be 0x00A0 and 0x0067 |
| 0x0002 | Edit Codes | 8 bytes per screen, 8 screens | Unencrypted. Edit codes are stored as a string format, padded with 3 zeros (ASCII 48). Edit codes of less than 5 characters should be preceded by zeros (ASCII 48) |
| 0x0042 | Colour Palette | 4 bytes per screen, 8 screens. | Each byte represents a Commodore Colour (i.e. 0:Black,1:White,2:Red,3:Cyan,4:Magenta,5:Green,6:Blue,7:Yellow,8:Orange, 9:Dark Yellow,10:Pink,11:Grey,12:Light Grey,13:Lime Green,14:Pale Blue,15:Silver) |
| 0x0062 | Character Data | 128 bytes per character, 48 characters | Each byte represents four pixels per character, across character then down (16x32): %11223344 for pixels 1,2,3 and 4 (2 bits each) representing one of four colours (0,1,2 or 3) |
| 0x1862 | Map Character Data | 8 bytes per character, 48 characters | Each byte represents four pixels per character, across character then down (4x8): %11223344 for pixels 1,2,3 and 4 (2 bits each) representing one of four colours (0,1,2 or 3) |
| 0x19E2 | Time Limits | 2 bytes per screen, 8 screens | This is in Hexadecimal-Coded-Decimal (e.g. 0x0012 and 0x0034 would be a time limit of 1234) |
| 0x19F2 | Password Data | 8 bytes per screen, 8 screens | Unencrypted. Terminated by SPACE (ASCII 32) |
| 0x1A32 | Map Data | 420 bytes per screen, 8 screens | The map is represented by a number which indicates which character (0-47). Each 8 characters are packed into 5 bytes, across map then down (28x24 characters): Chr 1 bits 0-4 are Byte 1 bits 0-4 Chr 2 bits 0-2 are Byte 1 bits 5-7 Chr 2 bits 3-4 are Byte 2 bits 0-1 Chr 3 bits 0-4 are Byte 2 bits 2-6 Chr 4 bit 0 is Byte 2 bit 7 Chr 4 bits 1-4 are Byte 3 bits 0-3 Chr 5 bits 0-3 are Byte 3 bits 4-7 Chr 5 bit 4 is Byte 4 bit 0 Chr 6 bits 0-4 are Byte 4 bits 1-5 Chr 7 bits 0-1 are Byte 4 bits 6-7 Chr 7 bits 2-4 are Byte 5 bits 0-2 Chr 8 bits 0-4 are Byte 5 bits 3-7 |
| 0x2752 | Unused | 16 bytes | Undefined - usually 0x0000 |
| 0x2762 | Transporters | 4 bytes per transporter, 4 transporters per screen, 8 screens. | Source x,y , Destination x,y. If no transporters, first byte is 0xFF |
| 0x27E2 | Unused | 6 bytes | Undefined - usually 0x0000 |
| Total file size: 10210 bytes |
Acorn Archimedes
| Offset into file | Content | Size | Format |
| 0x0000 | Password Data | 8 bytes per screen, 8 screens | Unknown |
| 0x0040 | Time Limits | 4 bytes per screen, 8 screens | [byte1] + [byte2] * 256 (i.e. First byte is LSB, second byte is MSB) Last two bytes are unused |
| 0x0060 | Edit Codes | 2 bytes per screen, 8 screens | [byte1] + [byte2] * 256 (i.e. First byte is LSB, second byte is MSB) NOTE: These codes are a red herring as the Archimedes version works out the codes based on the map contents |
| 0x0080 | Transporters | 8 bytes per transporter, 4 transporters per screen, 8 screens. | Bytes 1 and 2 are Source x,y , bytes 5 and 6 are Destination x,y. Encoding unknown |
| 0x0180 | Colour Palette | 4 bytes per colour, 16 colours per screen, 8 screens. | Bytes 2,3 and 4 represents the Red, Green and Blue levels of each of the 16 colours (although the sixteenth is unused) |
| 0x0380 | Map Data | 420 bytes per screen, 8 screens | The map is represented by a number which indicates which character (0-47). Each 8 characters are packed into 5 bytes, across map then down (28x24 characters): Chr 1 bits 0-4 are Byte 1 bits 0-4 Chr 2 bits 0-2 are Byte 1 bits 5-7 Chr 2 bits 3-4 are Byte 2 bits 0-1 Chr 3 bits 0-4 are Byte 2 bits 2-6 Chr 4 bit 0 is Byte 2 bit 7 Chr 4 bits 1-4 are Byte 3 bits 0-3 Chr 5 bits 0-3 are Byte 3 bits 4-7 Chr 5 bit 4 is Byte 4 bit 0 Chr 6 bits 0-4 are Byte 4 bits 1-5 Chr 7 bits 0-1 are Byte 4 bits 6-7 Chr 7 bits 2-4 are Byte 5 bits 0-2 Chr 8 bits 0-4 are Byte 5 bits 3-7 |
| 0x10A0 | Character Data | 512 bytes per character, 48 characters | Each byte represents two pixels per character, across character then down (32x32): Bits 4-7 are first pixel, bits 0-3 are second pixel, representing one of the sixteen colours |
| Total file size: 28832 bytes |
Please do not ask for the PC Format as it is subject to copyright. Also, I will not reveal the Repton The Lost Realms format until at least a year after release (if at all).
