RLEWB

Sorry! This text is pending correction of the English translation

Index

1 Description
2 Encoder format
3 Software to compress in RLEWB
4 C decoders
5 Assembler decoders
6 MSX BASIC
- 6.1 Decompress RLEWB to RAM
- 6.2 Decompress RLEWB to VRAM
7 Visual Basic dotnet
- 7.1 RLEWB encoder
8 Acknowledgments

1 Description

RLEWB is a compressor of the RLE type (Run-Length Encoding), with the advantage that it improves the results in data sequences where there are not many series of repeated values, because it does not penalize for the simple values.

This repository collects resources to use this compression algorithm definition. It includes the encoder for Visual Basic .net and the decoder for C, Assembler and MSX BASIC.

This project is an Open Source library.

It is primarily designed for graphical data from the TMS9918A, where repetitions of values are often found, especially in the color table.

In the source code you can find applications for testing and learning purposes.

It is inspired by the Wonder Boy RLE compression algorithm, published on the SMS POWER! WEBSITE.

2 Encoder format

 CD = Control Digit = $80

 CD + $0       --> When the value to be written to the output is equal to the Control Digit
 CD + $FF      --> End - Decompressed until it finds this value.
 CD +  nn + dd --> Repeat nn+1 ($2 to $FE) value equivalent to 3 up to 255 repetitions. 
                   In dd is the value to repeat.
 dd (!= CD)    --> Raw data. Values without repetition.

3 Software to compress in RLEWB

RLE-WB compressor for MSX Fusion-C by Eric Boez. MacOS Windows 64bits Linux 64bits
ByteniZ3R devtool Another generator of data tables in Bytes. .net 4

4 C decoders

For decompression directly to VRAM, two libraries (.rel) are available, depending on the execution environment (MSX-DOS or BIOS ROM/BASIC).

4.1 Requirements

4.2 Decompress RLEWB to RAM

unRLEWBtoRAM

unRLEWBtoRAM
Decompress RLEWB data to RAM
Function	void unRLEWBtoRAM (unsigned int sourceADDR, unsigned int targetADDR)
Input	unsigned int	source data address
	unsigned int	target VRAM address

Example

// RLE WB compressed - Original size= 2048 - Compress size= 33
const char DATA_COL[]={
  0x80,0xFE,0xFC,0x80,0xFE,0xFC,0xFC,0xFC,0x80,0x3F,0xF2,0x80,
  0x0F,0x51,0x80,0x0F,0xF2,0x80,0x0F,0x51,0x80,0x0F,0xF2,0x80,
  0x07,0x51,0x80,0xAF,0xF2,0x80,0x07,0x51,0x80,0x17,0xF2,0x80,
  0x07,0x51,0x80,0x0F,0xF2,0x80,0x07,0x51,0x80,0x07,0xF2,0x80,
  0x07,0x51,0x80,0xAF,0xF2,0x80,0x07,0x51,0x80,0x17,0xF2,0x80,
  0x07,0x51,0x80,0x0F,0xF2,0x80,0x07,0x51,0x80,0x07,0xF2,0x80,
  0x07,0x51,0x80,0xB7,0xF2,0x80,0x0F,0x51,0x80,0x0F,0xF2,0x80,
  0x0F,0x51,0x80,0x0F,0xF2,0x80,0x17,0x51,0x80,0x67,0xF2,0x80,
  0xFE,0xF3,0x80,0xFE,0xF3,0xF3,0xF3,0x80,0xFF};

void main()
{
    unRLEWBtoRAM ((unsigned int) DATA_COL, 0xD000);
}

unRLEWBRAM (for Assembler inline)

unRLEWBRAM
Decompress RLEWB data to RAM
Input	HL	source data address
	DE	target RAM address

Example

void SetDATA() __naked
{
__asm 
  ;decompress to RAM
  ld   HL,#DATA_COL
  ld   DE,#0xD000 ;RAM addr
  call unRLEWBRAM
  
  ;copy to VRAM
  ld   HL,#0xD000 ;RAM addr
  ld   DE,#0x2000 ;VRAM addr
  ld   BC,#0x800  ;length
  call 0x005C     ;LDIRVM
  
  ret
  
DATA_COL:
  .db 0x80,0xFE,0xFC,0x80,0xFE,0xFC,0xFC,0xFC,0x80,0x3F,0xF2,0x80
  .db 0x0F,0x51,0x80,0x0F,0xF2,0x80,0x0F,0x51,0x80,0x0F,0xF2,0x80
  .db 0x07,0x51,0x80,0xAF,0xF2,0x80,0x07,0x51,0x80,0x17,0xF2,0x80
  .db 0x07,0x51,0x80,0x0F,0xF2,0x80,0x07,0x51,0x80,0x07,0xF2,0x80
  .db 0x07,0x51,0x80,0xAF,0xF2,0x80,0x07,0x51,0x80,0x17,0xF2,0x80
  .db 0x07,0x51,0x80,0x0F,0xF2,0x80,0x07,0x51,0x80,0x07,0xF2,0x80
  .db 0x07,0x51,0x80,0xB7,0xF2,0x80,0x0F,0x51,0x80,0x0F,0xF2,0x80
  .db 0x0F,0x51,0x80,0x0F,0xF2,0x80,0x17,0x51,0x80,0x67,0xF2,0x80
  .db 0xFE,0xF3,0x80,0xFE,0xF3,0xF3,0xF3,0x80,0xFF

__endasm;
}

4.3 Decompress RLEWB to VRAM

MSX with BIOS (ROM or MSX BASIC) unRLEWBtoVRAM.rel
MSX-DOS unRLEWBtoVRAM_MSXDOS.rel
unRLEWBtoVRAM.h

unRLEWBtoVRAM

unRLEWBtoVRAM
Decompress RLEWB data to VRAM
Function	void unRLEWBtoVRAM (unsigned int sourceADDR, unsigned int targetADDR)
Input	unsigned int	source data address
	unsigned int	target VRAM address

Example

// RLE WB compressed - Original size= 2048 - Compress size= 33
const char DATA_COL[]={
  0x80,0xFE,0xFC,0x80,0xFE,0xFC,0xFC,0xFC,0x80,0x3F,0xF2,0x80,
  0x0F,0x51,0x80,0x0F,0xF2,0x80,0x0F,0x51,0x80,0x0F,0xF2,0x80,
  0x07,0x51,0x80,0xAF,0xF2,0x80,0x07,0x51,0x80,0x17,0xF2,0x80,
  0x07,0x51,0x80,0x0F,0xF2,0x80,0x07,0x51,0x80,0x07,0xF2,0x80,
  0x07,0x51,0x80,0xAF,0xF2,0x80,0x07,0x51,0x80,0x17,0xF2,0x80,
  0x07,0x51,0x80,0x0F,0xF2,0x80,0x07,0x51,0x80,0x07,0xF2,0x80,
  0x07,0x51,0x80,0xB7,0xF2,0x80,0x0F,0x51,0x80,0x0F,0xF2,0x80,
  0x0F,0x51,0x80,0x0F,0xF2,0x80,0x17,0x51,0x80,0x67,0xF2,0x80,
  0xFE,0xF3,0x80,0xFE,0xF3,0xF3,0xF3,0x80,0xFF};

void main()
{  
  unRLEWBtoVRAM ((unsigned int) DATA_COL, 0x2000);
}

unRLEWBVRAM (for Assembler inline)

unRLEWBVRAM
Decompress RLEWB data to VRAM
Input	HL	source data address
	DE	target VRAM address

Example

void SetGFX() __naked
{
__asm  
  ld   HL,#DATA_COL
  ld   DE,#0x2000   ;BASE11 Color Table
  call unRLEWBVRAM
  
  ret  
  
; RLE WB compressed - Original size= 2048 - Compress size= 105  
DATA_COL:
  .db 0x80,0xFE,0xFC,0x80,0xFE,0xFC,0xFC,0xFC,0x80,0x3F,0xF2,0x80
  .db 0x0F,0x51,0x80,0x0F,0xF2,0x80,0x0F,0x51,0x80,0x0F,0xF2,0x80
  .db 0x07,0x51,0x80,0xAF,0xF2,0x80,0x07,0x51,0x80,0x17,0xF2,0x80
  .db 0x07,0x51,0x80,0x0F,0xF2,0x80,0x07,0x51,0x80,0x07,0xF2,0x80
  .db 0x07,0x51,0x80,0xAF,0xF2,0x80,0x07,0x51,0x80,0x17,0xF2,0x80
  .db 0x07,0x51,0x80,0x0F,0xF2,0x80,0x07,0x51,0x80,0x07,0xF2,0x80
  .db 0x07,0x51,0x80,0xB7,0xF2,0x80,0x0F,0x51,0x80,0x0F,0xF2,0x80
  .db 0x0F,0x51,0x80,0x0F,0xF2,0x80,0x17,0x51,0x80,0x67,0xF2,0x80
  .db 0xFE,0xF3,0x80,0xFE,0xF3,0xF3,0xF3,0x80,0xFF
__endasm;
}

5 Assembler decoders

It is available with support for cross-development assemblers: asMSX, Sjasm and tniASM.

An adapted source is available for all three assemblers but it doesn't work with the current version of asMSX v.1.0.1, as there is a pending Bug related to Conditional Assembly [#90](https://github.com/Fubukimaru/asMSX/issues/90). Therefore you will find asMSX-specific sources for BIOS-based environments (ROM and BASIC) and MSX-DOS.

You can add the following Labels to your main code, to configure the decompressor for different environments:

Note: For Sjasm assembler, use DEFINE + Label

Identify the assembler (ASMSX , SJASM or TNIASM) Default: ASMSX/SJASM
Runtime (MSXROM , MSXDOS or MSXBASIC) Default: MSXROM/MSXBASIC
DIRECTRANGE if you have a compressor that generated a range from 3 to 254 repetitions.

5.1 Requirements

A cross assembler:

asMSX v1.0.1
Sjasm v0.42 by XL2S Entertainment
tniASM v0.45 by The New Image

5.2 unRLEWBtoRAM

For Sjasm and tniASM unRLEWBtoRAM.asm
For asMSX unRLEWBtoRAM.asm

unRLEWBtoRAM
Decompress RLEWB data to RAM
Input	HL	source data address
	DE	target RAM address

Example

  ;decompress to RAM
  ld   HL,DATA_COL
  ld   DE,0xD000
  call unRLEWBtoRAM
  
  ;copy to VRAM
  ld   HL,#0xD000 ;RAM addr
  ld   DE,#0x2000 ;VRAM addr
  ld   BC,#800    ;length
  call 0x005C     ;LDIRVM
  
  ret

; RLE WB compressed - Original size= 2048 - Compress size= 105  
DATA_COL:
  db $80,$FE,$FC,$80,$FE,$FC,$FC,$FC,$80,$3F,$F2,$80,$0F,$51,$80,$0F
  db $F2,$80,$0F,$51,$80,$0F,$F2,$80,$07,$51,$80,$AF,$F2,$80,$07,$51
  db $80,$17,$F2,$80,$07,$51,$80,$0F,$F2,$80,$07,$51,$80,$07,$F2,$80
  db $07,$51,$80,$AF,$F2,$80,$07,$51,$80,$17,$F2,$80,$07,$51,$80,$0F
  db $F2,$80,$07,$51,$80,$07,$F2,$80,$07,$51,$80,$B7,$F2,$80,$0F,$51
  db $80,$0F,$F2,$80,$0F,$51,$80,$0F,$F2,$80,$17,$51,$80,$67,$F2,$80
  db $FE,$F3,$80,$FE,$F3,$F3,$F3,$80,$FF

5.3 unRLEWBtoVRAM

For Sjasm and tniASM unRLEWBtoRAM.asm
For asMSX on MSX BIOS (ROM or BASIC) unRLEWBtoRAM.asm
For asMSX on MSX-DOS unRLEWBtoRAM.asm

unRLEWBtoVRAM
Decompress RLEWB data to VRAM
Input	HL	source data address
	DE	target VRAM address

Example

  ld   HL,DATA_COL
  ld   DE,$2000   ;BASE11 Color Table
  call unRLEWBtoVRAM            
  ret

; RLE WB compressed - Original size= 2048 - Compress size= 105  
DATA_COL:
  db $80,$FE,$FC,$80,$FE,$FC,$FC,$FC,$80,$3F,$F2,$80,$0F,$51,$80,$0F
  db $F2,$80,$0F,$51,$80,$0F,$F2,$80,$07,$51,$80,$AF,$F2,$80,$07,$51
  db $80,$17,$F2,$80,$07,$51,$80,$0F,$F2,$80,$07,$51,$80,$07,$F2,$80
  db $07,$51,$80,$AF,$F2,$80,$07,$51,$80,$17,$F2,$80,$07,$51,$80,$0F
  db $F2,$80,$07,$51,$80,$07,$F2,$80,$07,$51,$80,$B7,$F2,$80,$0F,$51
  db $80,$0F,$F2,$80,$0F,$51,$80,$0F,$F2,$80,$17,$51,$80,$67,$F2,$80
  db $FE,$F3,$80,$FE,$F3,$F3,$F3,$80,$FF

6 MSX BASIC

The RLEWB encoder is so simple that it can be easily programmed in MSX BASIC.

Although it may not seem like it, it can be faster than directly reading the data and dumping it to memory, since repeated data is written faster, although the main advantage is that you can reduce the size of your program.

Remember that when writing the DATA in BASIC it is not necessary to include the zeros.

The best option would be to include the decompression routine in the binary itself that includes the data and execute it on load, but it would be a task that you would have to do yourself since there is no tool that makes it easy for you.

6.1 Decompress RLEWB to RAM

9000 '=================================
9010 ' unRLEWB to RAM for MSX BASIC
9020 ' Decompress RLEWB data to RAM
9030 ' Input: 
9040 '  RESTORE [line] <-- DATAs
9050 '              DE <-- RAM address
9060 '=================================
9100 READ A
9110 IF A=&H80 THEN 9150
9120 POKE DE,A
9130 DE=DE+1
9140 GOTO 9100
9150 READ A
9160 IF A=&HFF THEN RETURN
9170 IF A=0 THEN A=&H80:GOTO 9120
9180 READ B
9190 FOR DE=DE TO DE+A
9200 POKE DE,B
9210 NEXT
9220 GOTO 9100

To use it, you will have to do a RESTORE with the line number where the data starts, provide the value of the RAM address to the DE variable and do a GOSUB 9100.

Example

100 REM Test unRLEWB to RAM
110 RESTORE 1020
120 DE=&HE000
130 GOSUB 9100
140 END
1000 REM Tileset Pattern data All BANKs
1010 REM RLE WB compressed - Original size= 6144 - Compress size= 1368
1020 DATA 128,254,,128,10,,1,3,7,15,31,63,15,127,128,213
1030 DATA 255,240,254,128,5,255,,,128,,192,224,240,248,252,128
1040 DATA 15,,63,128,2,127,128,3,255,248,224,192,128,,128,
1050 DATA 128,210,,31,7,3,1,1,128,2,,252,128,2,254,128
...
1870 DATA 128,254,,128,205,,128,255

6.2 Decompress RLEWB to VRAM

9000 '=================================
9010 ' unRLEWB to VRAM for MSX BASIC
9020 ' Decompress RLEWB data to VRAM
9030 ' Input: 
9040 '  RESTORE [line] <-- DATAs
9050 '              DE <-- VRAM address
9060 '=================================
9100 READ A
9110 IF A=&H80 THEN 9150
9120 VPOKE DE,A
9130 DE=DE+1
9140 GOTO 9100
9150 READ A
9160 IF A=&HFF THEN RETURN
9170 IF A=0 THEN A=&H80:GOTO 9120
9180 READ B
9190 FOR DE=DE TO DE+A
9200 VPOKE DE,B
9210 NEXT
9220 GOTO 9100

To use it, you will have to do a RESTORE with the line number where the data starts, provide the value of the VRAM address to the DE variable and do a GOSUB 9100.

Example

You can find the complete example in here.

100 REM Test unRLEWB to VRAM
110 DEFINT A-Z
120 COLOR 15,4,4
130 SCREEN 2
140 RESTORE 1020
150 DE=BASE(12)
160 GOSUB 9100
170 IF INKEY$="" THEN 170
180 END
1000 REM Tileset Pattern data All BANKs
1010 REM RLE WB compressed - Original size= 6144 - Compress size= 1368
1020 DATA 128,254,,128,10,,1,3,7,15,31,63,15,127,128,213
1030 DATA 255,240,254,128,5,255,,,128,,192,224,240,248,252,128
1040 DATA 15,,63,128,2,127,128,3,255,248,224,192,128,,128,
1050 DATA 128,210,,31,7,3,1,1,128,2,,252,128,2,254,128
...
1870 DATA 128,254,,128,205,,128,255

7 Visual Basic dotnet

7.1 RLEWB encoder

VisualBasic_dotnet/RLEWB.vb

GetRLEWB
Function	GetRLEWB(ByVal data() As Byte) As Byte()
Compress input Byte Array
Input	Byte()	Raw data
Output	Byte()	Compress data

8 Acknowledgments

I want to give a special thanks to all those who freely share their knowledge with the Retrocomputing developer community.

SMS Power > WEB
SDsnatcher > WEB
Eric Boez > gitHub
Avelino Herrera > WEB
Nerlaska > Blog
MSXKun/Paxanga soft > WEB
Fubukimaru gitHub
Marq > Marq
Sapphire/Z80ST > WEB
Andrear > Blog
Konamiman gitHub WEB
MSX Assembly Page > WEB
Portar MSX Tech Doc > WEB
MSX Resource Center > WEB
Karoshi MSX Community > WEB
BlueMSX emulator >> WEB
OpenMSX emulator >> WEB
WebMSX emulator by Paulo A. Peccin >> gitHub
fMSX emulator by Marat Fayzullin WEB
Meisei emulator by Hap >> ?

Fubukimaru / Z80_RLEWB

RLEWB

Sorry! This text is pending correction of the English translation

Index

1 Description

2 Encoder format

3 Software to compress in RLEWB

4 C decoders

4.1 Requirements

4.2 Decompress RLEWB to RAM

unRLEWBtoRAM

unRLEWBRAM (for Assembler inline)

4.3 Decompress RLEWB to VRAM

unRLEWBtoVRAM

unRLEWBVRAM (for Assembler inline)

5 Assembler decoders

5.1 Requirements

5.2 unRLEWBtoRAM

5.3 unRLEWBtoVRAM

6 MSX BASIC

6.1 Decompress RLEWB to RAM

6.2 Decompress RLEWB to VRAM

7 Visual Basic dotnet

7.1 RLEWB encoder

8 Acknowledgments

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