fixed plain .prg version

actually it takes a "lot" of space more, but it is not a problem and it works,
anyhow a future version with a "fast" loader is required

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "liblzg"]
+	path = liblzg
+	url = https://github.com/mbitsnbites/liblzg.git

LICENSE

@@ -1 +0,0 @@
-https://www.gnu.org/licenses/gpl-3.0.txt

LICENSE.md

@@ -0,0 +1,6 @@
+# License
+* [snake6502](https://git.giomba.it/giomba/snake6502) has been written by giomba and is released under the terms of the [GNU General Public License 3.0](https://www.gnu.org/licenses/gpl-3.0.txt)
+
+* [liblzg](https://liblzg.bitsnbites.eu/) has been written by Marcus Geelnard and is released under the terms of the [zlib license](https://opensource.org/licenses/Zlib)
+
+

Makefile

@@ -1,18 +1,31 @@
 .POSIX:
 
 ASM=$(wildcard src/*.asm)
-RES=res.bin/amour.sid res.bin/levels.bin
-
-ifeq "$(CARTRIDGE)" "1"
-	FORMAT:=3
-else
-	FORMAT:=1
-endif
+RES=res.bin/amour.sid res.bin/levels.bin res.bin/unlzg.bin
 
 .PHONY: debug env clean
 
-bin/snake.prg: env $(ASM) $(RES) bin/explodefont
-	dasm src/main.asm -Isrc/ -DSYSTEM=64 -DDEBUG=$(DEBUG) -DVERBOSE=$(VERBOSE) -DCARTRIDGE=$(CARTRIDGE) -f$(FORMAT) -sbuild/symbols.txt -obin/snake.prg
+bin/snake.bin: bin/snake.pack.lz
+	dasm src/cart.asm -Isrc/ -DVERBOSE=$(VERBOSE) -f3 -sbuild/cart.symbols.txt -obin/snake.bin
+
+#bin/tape.prg: bin/snake.pack.lz.file
+#	dasm src/tape.asm -Isrc/ -DVERBOSE=$(VERBOSE) -f1 -sbuild/tape.sybols.txt -obin/tape.prg
+
+#bin/snake.pack.lz.file: bin/snake.pack.lz
+#	echo -e "\x00\x80" > bin/snake.pack.lz.file
+#	cat bin/snake.pack.lz >> bin/snake.pack.lz.file
+
+bin/snake.prg: bin/snake.pack
+	dasm src/prg.asm -Isrc/ -DVERBOSE=$(VERBOSE) -f1 -sbuild/prg.symbols.txt -obin/snake.prg
+
+bin/snake.pack: env $(ASM) $(RES) bin/explodefont
+	dasm src/main.asm -Isrc/ -DSYSTEM=64 -DDEBUG=$(DEBUG) -DVERBOSE=$(VERBOSE) -DCARTRIDGE=$(CARTRIDGE) -f3 -sbuild/pack.symbols.txt -obin/snake.pack
+
+bin/snake.pack.lz: bin/snake.pack liblzg/src/tools/lzg
+	liblzg/src/tools/lzg bin/snake.pack > bin/snake.pack.lz
+
+liblzg/src/tools/lzg:
+	cd liblzg/src && make
 
 clean:
 	rm -rf {build,bin,res.bin}
@@ -29,6 +42,9 @@ res.bin/amour.sid:
 res.bin/levels.bin: bin/level res.org/levels.txt
 	bin/level < res.org/levels.txt > res.bin/levels.bin
 
+res.bin/unlzg.bin:
+	cp res.org/unlzg.bin res.bin/unlzg.bin
+
 bin/level: util/rlevel.cpp
 	g++ -o bin/level util/rlevel.cpp
 

README.md

@@ -13,25 +13,37 @@ You need the GNU compiler collection and the [dasm](https://dasm-assembler.githu
 ```
 $ make
 ```
+Interesting targets:
+
+* ```make bin/snake.bin``` produces .bin, ready to be burnt on an 8K EEPROM for making a cartridge (default)
+* ```make bin/snake.prg``` produces .prg for the emulator, ready to be used on tape/disk
+* ```make tape/disk``` (fastloader, to be done)
+
 You can also define the following environment variables:
 
 ```$ DEBUG=1 make```        build with debugging artifacts
 
 ```$ VERBOSE=1 make```      output useful info during compilation
 
-```$ CARTRIDGE=1 make```    produces an 8K bin ready to be burnt to an *PROM
-
 ## Developer docs
+### Package
+The whole program is assembled into a ```snake.pack``` binary blob with the following structure.
+
+Absolute    | Offset      | Description
+------------|-------------|------------
+```$1000``` | ```$0000``` | load address
+```$2800``` | ```$1800``` | entry point (start address)
+
 ### Memory map
 Address               | PRG   | Description
 ----------------------|-------|------------
 ```$0000 - $0001```   | no    | hardware
 ```$0002 - $00FF```   | no    | zero page pointers
-```$0100 - $07FF```   | no    | *free ram*
-```$0800 - $0FFF```   | yes   | autostart (BASIC or cartridge) + Low Program Segment
-```$1000 - $1FFF```   | yes   | SID tune + Middle Program Segment
+```$0100 - $01FF```   | no    | stack page
+```$0200 - $07FF```   | no    | *free ram*
+```$1000 - $1FFF```   | yes   | SID tune
 ```$2000 - $27FF```   | yes   | custom char
-```$2800 - $xxxx```   | yes   | High Program Segment (only needed part used)
+```$2800 - $xxxx```   | yes   | Program segment (only needed part used)
 ```$xxxx - $CCFF```   | no    | *free ram*
 ```$CD00 - $CDFF```   | no    | data segment (not-initialized vars)
 ```$CE00 - $CEFF```   | no    | list X
@@ -39,9 +51,14 @@ Address               | PRG   | Description
 ```$D000 - $DFFF```   | no    | I/O
 ```$E000 - $FFFF```   | no    | Kernal
 
-Note: program (code) segments have been put in all possible free spots in order to squeeze the game into an 8K cartridge.
+### Compression
+```snake.pack``` is compressed into ```snake.pack.lz``` using [liblzg](https://github.com/mbitsnbites/liblzg), to save space in order to fit the game in a *PROM.
 
-### Custom charset
+### Decompression
+```cart.asm``` is located at ```$8000``` (standard org address for C64 cartridges), and contains the decompression routine and the ```snake.pack.lz```. It decompresses ```snake.pack.lz``` back to ```$1000```, and jumps to its entry point at ```$2800```.
+
+### Miscellanea
+#### Custom charset
 Index           | Description
 ----------------|-------------
 ```$00 - $1F``` |   A-Z (space first)
@@ -50,8 +67,3 @@ Index           | Description
 ```$50 - $5F``` |   hex digits, reversed
 ```$60 -    ``` |   game tiles
 
-### Cartridge
-Cartridge version is at $8000 and simply copies itself back at $800.
-
-Cartridge version can not be built with DEBUG=1 flag due to size constraints.
-

liblzg

@@ -0,0 +1 @@
+Subproject commit 182b56cb36843720f38eff2ec30db1deac4e85bd

src/cart.asm

@@ -1,11 +1,15 @@
-#if VERBOSE = 1
-LASTINIT SET .
-#endif
+    processor 6502
+
+    SEG.U zeropageSegment
+    org $02
+    INCLUDE "zeropage.asm"
+
+    SEG cartridgeSegment
+    org $8000
 
 cartridge SUBROUTINE
-
-    WORD #$8009
-    WORD #$801a
+    WORD .coldstart
+    WORD .warmstart
 
     ; CBM80 in PETSCII (cartridge signature for autostart)
     BYTE #$c3,#$c2,#$cd,#$38,#$30
@@ -20,28 +24,35 @@ cartridge SUBROUTINE
     cli
 
 .warmstart:
-    ; Copy cartridge content into proper memory location
-    ldx #$20
-    lda #$0
-    tay
+    ; address of input compressed data
+    lda #<.lzpack
     sta srcPointer
-    sta dstPointer
-    lda #>cartridgeStart
+    lda #>.lzpack
     sta srcPointer + 1
-    lda #$08
-    sta dstPointer + 1
-.loop:
-    lda (srcPointer),y
-    sta (dstPointer),y
-    iny
-    bne .loop
-    inc srcPointer + 1
-    inc dstPointer + 1
-    dex
-    bne .loop
 
-    jmp start
+    ; address of output decompressed data
+    lda #$00
+    sta dstPointer
+    lda #$10
+    sta dstPointer + 1
+    jsr inflate
+
+    ; jump to program entry
+    jmp $2800
+
+    ; compressed pack
+.lzpack:
+    INCBIN "bin/snake.pack.lz"
+
+    ; decompression util
+    INCLUDE "lzgmini.asm"
 
 #if VERBOSE = 1
-    ECHO "cart.asm @ ",LASTINIT,"len:",(. - LASTINIT)
-#endif
+    ECHO "8k CARTRIDGE SIZE:",(. - $8000),"=",[(. - $8000)d]
+    ECHO "SPACE LEFT:",($9fff - .),"=",[($9fff - .)d]
+#endif
+
+    ; force filler for the *PROM
+. = $9fff
+    BYTE #$ff
+

src/font.asm

@@ -2564,5 +2564,5 @@ LASTINIT SET .
    BYTE #%00000000
 
 #if VERBOSE = 1
-    ECHO "tggs.asm @ ",LASTINIT,"len:",(. - LASTINIT)
-#endif
+    ECHO "font.asm @ ",LASTINIT,"len:",(. - LASTINIT)
+#endif

src/lzgmini.asm

@@ -0,0 +1,242 @@
+inflate SUBROUTINE
+.inEnd EQU 2
+.offset EQU 4
+.length EQU 6
+.symbol EQU 25
+.marker1 EQU 30
+.marker2 EQU 31
+.marker3 EQU 32
+.marker4 EQU 33
+.copy EQU 34
+
+    clc
+    ldy #10
+    lda (srcPointer),y
+    adc srcPointer
+	sta	.inEnd
+	dey
+	lda	(srcPointer),y
+	adc	srcPointer + 1
+	sta	.inEnd + 1
+	clc
+	lda	.inEnd
+	adc	#16
+	sta	.inEnd
+	lda	.inEnd + 1
+	adc	#0
+	sta	.inEnd + 1
+
+	; Get the marker symbols
+	ldy	#16
+	lda	(srcPointer),y
+	sta	.marker1
+	iny
+	lda	(srcPointer),y
+	sta	.marker2
+	iny
+	lda	(srcPointer),y
+	sta	.marker3
+	iny
+	lda	(srcPointer),y
+	sta	.marker4
+
+	; Skip header + marker symbols (16 + 4 bytes)
+	clc
+	lda	srcPointer
+	adc	#20
+	sta	srcPointer
+	lda	srcPointer + 1
+	adc	#0
+	sta	srcPointer + 1
+
+	; Main decompression loop
+	ldy	#0				; Make sure that Y is zero
+.mainloop:
+	lda	srcPointer		; done?
+	cmp	.inEnd
+	bne	.notdone
+	lda	srcPointer + 1
+	cmp	.inEnd + 1
+	bne	.notdone
+	rts
+.notdone:
+	lda	(srcPointer),y				; A = symbol
+	sta	.symbol
+    sta $d020
+	inc	srcPointer
+	bne	.noinc1
+	inc	srcPointer + 1
+.noinc1:
+	cmp	.marker1			; Marker1?
+	beq	.domarker1
+	cmp	.marker2			; Marker2?
+	beq	.domarker2
+	cmp	.marker3			; Marker3?
+	beq	.domarker3
+	cmp	.marker4			; Marker4?
+	beq	.domarker4
+.literal:
+	lda	.symbol
+	sta	(dstPointer),y			; Plain copy
+	inc	dstPointer
+	bne	.mainloop
+	inc	dstPointer + 1
+	bne	.mainloop
+
+.domarker1:
+	jmp	.domarker1b
+
+	; marker4 - "Near copy (incl. RLE)"
+.domarker4:
+	lda	(srcPointer),y
+	inc	srcPointer
+	bne	.noinc3
+	inc	srcPointer + 1
+.noinc3:
+	cmp	#0
+	beq	.literal				; Single occurance of the marker symbol (rare)
+	tax
+	lsr
+	lsr
+	lsr
+	lsr
+	lsr
+	sta	.offset
+	inc	.offset
+	lda	#0
+	sta	.offset + 1			; offset = (b >> 5) + 1
+	txa
+	and	#$1f
+	tax
+	lda	.LZG_LENGTH_DECODE_LUT,x
+	sta	.length				; length = .LZG_LENGTH_DECODE_LUT[b & 0x1f]
+	jmp	.docopy
+
+	; marker3 - "Short copy"
+.domarker3:
+	lda	(srcPointer),y
+	inc	srcPointer
+	bne	.noinc4
+	inc	srcPointer + 1
+.noinc4:
+	cmp	#0
+	beq	.literal				; Single occurance of the marker symbol (rare)
+	tax
+	lsr
+	lsr
+	lsr
+	lsr
+	lsr
+	lsr
+	clc
+	adc	#3
+	sta	.length				; length = (b >> 6) + 3
+	txa
+	and	#$3f
+	adc	#8
+	sta	.offset
+	lda	#0
+	sta	.offset + 1			; offset = (b & 0x3f) + 8
+	beq	.docopy
+
+	; marker2 - "Medium copy"
+.domarker2:
+	lda	(srcPointer),y
+	inc	srcPointer
+	bne	.noinc5
+	inc	srcPointer + 1
+.noinc5:
+	cmp	#0
+	beq	.literal				; Single occurance of the marker symbol (rare)
+	tax
+	lsr
+	lsr
+	lsr
+	lsr
+	lsr
+	sta	.offset + 1
+	lda	(srcPointer),y
+	inc	srcPointer
+	bne	.noinc6
+	inc	srcPointer + 1
+.noinc6:
+	clc
+	adc	#8
+	sta	.offset
+	bcc	.noinc7
+	inc	.offset + 1			; offset = (((b & 0xe0) << 3) | b2) + 8
+.noinc7:
+	txa
+	and	#$1f
+	tax
+	lda	.LZG_LENGTH_DECODE_LUT,x
+	sta	.length				; length = .LZG_LENGTH_DECODE_LUT[b & 0x1f]
+	bne	.docopy
+
+.literal2:
+	jmp	.literal
+
+	; marker1 - "Distant copy"
+.domarker1b:
+	lda	(srcPointer),y
+	inc	srcPointer
+	bne	.noinc8
+	inc	srcPointer + 1
+.noinc8:
+	cmp	#0
+	beq	.literal2			; Single occurance of the marker symbol (rare)
+	and	#$1f
+	tax
+	lda	.LZG_LENGTH_DECODE_LUT,x
+	sta	.length				; length = .LZG_LENGTH_DECODE_LUT[b & 0x1f]
+	lda	(srcPointer),y
+	inc	srcPointer
+	bne	.noinc9
+	inc	srcPointer + 1
+.noinc9:
+	sta	.offset + 1
+	lda	(srcPointer),y
+	inc	srcPointer
+	bne	.noinc10
+	inc	srcPointer + 1
+.noinc10:
+	clc
+	adc	#$08
+	sta	.offset
+	lda	.offset + 1
+	adc	#$08
+	sta	.offset + 1			; offset = ((b2 << 8) | (*src++)) + 2056
+
+	; Copy corresponding data from history window
+.docopy:
+	sec
+	lda	dstPointer
+	sbc	.offset
+	sta	.copy
+	lda	dstPointer + 1
+	sbc	.offset + 1
+	sta	.copy + 1
+.loop1:
+    lda	(.copy),y
+	sta	(dstPointer),y
+	iny
+	cpy	.length
+	bne	.loop1
+	ldy	#0				; Make sure that Y is zero
+
+	clc
+	lda	dstPointer
+	adc	.length
+	sta	dstPointer
+	bcc	.noinc11
+	inc	dstPointer + 1
+.noinc11:
+	jmp	.mainloop
+
+; Lookup Table for decoding the copy length parameter
+.LZG_LENGTH_DECODE_LUT
+	BYTE    2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,35,48,72,128
+
+
+
+

src/main.asm

@@ -20,34 +20,6 @@
     ECHO "End of zeropage variables. Space left: ",($90 - .)
 #endif
 
-; Initialized segments
-; ----------------------------------------------------------------------
-    SEG autostartSegment
-#if CARTRIDGE = 0
-    org $801
-    INCLUDE "basic.asm" ; BASIC _MUST_ stay at this address
-#else
-    org $800
-    INCLUDE "cart.asm"
-#endif
-    INCLUDE "initdata.asm"
-
-; Program "Segment" Low
-; ----------------------------------------------------------------------
-; You just have to fill this empty space, don't you think so? ;-)
-    INCLUDE "game.asm"
-    INCLUDE "gameover.asm"
-    INCLUDE "introreset.asm"
-    INCLUDE "program.asm"
-    INCLUDE "subroutines.asm"
-    INCLUDE "levels.asm"
-    INCLUDE "intro1.asm"
-; Note: some code had to be included at an higher address
-
-#if VERBOSE = 1
-    ECHO "End of Low Program Segment. Space left:",($1000 - .)
-#endif
-
 ; SID tune (previously properly cleaned, see HVSC)
 ; ----------------------------------------------------------------------
     SEG sidSegment
@@ -55,47 +27,36 @@
 sidtune:
     INCBIN "../res.bin/amour.sid"
 #if VERBOSE = 1
-    ECHO "End of SIDtune at ",.
-#endif
-    INCLUDE "multicolor.asm"
-    INCLUDE "levelreset.asm"
-    INCLUDE "outro.asm"
-#if VERBOSE = 1
-    ECHO "End of Middle Program Segment. Space left:",($2000 - .)
+    ECHO "End of SIDtune at ",.,"Space left:",($2000 - .)
 #endif
 
 ; Font Data
 ; ----------------------------------------------------------------------
-    SEG tggsSegment
+    SEG fontSegment
     org $2000
 ; This binary data that defines the font is exactly 2kB long ($800)
-tggsFont:
-    INCLUDE "tggs.asm"
+    INCLUDE "font.asm"
 
-; Program Segment High
+; Program Segment
 ; ----------------------------------------------------------------------
-
+    SEG programSegment
+    org $2800
+    INCLUDE "program.asm"
+    INCLUDE "initdata.asm"
+    INCLUDE "game.asm"
+    INCLUDE "gameover.asm"
+    INCLUDE "introreset.asm"
+    INCLUDE "subroutines.asm"
+    INCLUDE "levels.asm"
+    INCLUDE "intro1.asm"
+    INCLUDE "multicolor.asm"
+    INCLUDE "levelreset.asm"
+    INCLUDE "outro.asm"
 #if VERBOSE = 1
-    ECHO "End of High Program Segment at: ",.,"Space left:",($cd00 - .)
+    ECHO "End of program segment at:",.
+    ECHO "PACK SIZE:",(. - $1000),"=",[(. - $1000)d]
 #endif
 
-#if VERBOSE = 1
-#if CARTRIDGE = 0
-    ; +2 because of PRG header
-    ECHO "PRG size:",([. - $801 + 2]d),"dec"
-#else
-    ECHO "BIN size:",([. - $800]d),"dec"
-#endif
-#endif
-
-; Uninitialized segments
-; ----------------------------------------------------------------------
-; Cartridge locations
-; -------------------
-    SEG.U cartridgeSegment
-    org $8000
-cartridgeStart:
-
 ; Data variables
 ; -----------------
     SEG.U dataSegment
@@ -113,10 +74,8 @@ listX DS 256
 listY DS 256
 
 ;
-; coded during december 2017
+; coded 2017, 2018, 2019, 2020
 ; by giomba -- giomba at glgprograms.it
 ; this software is free software and is distributed
 ; under the terms of GNU GPL v3 license
 ;
-
-; vim: set expandtab tabstop=4 shiftwidth=4:

src/prg.asm

@@ -0,0 +1,26 @@
+    processor 6502
+
+    SEG.U
+    org $02
+    INCLUDE "zeropage.asm"
+
+    SEG autostart
+    org $801
+autostartRoutine SUBROUTINE
+    ; this is at $801
+    ; and it MUST be exactly at this location in order to autostart
+	; 10 SYS2060 ($80c) BASIC autostart
+    BYTE #$0b,#$08,#$0a,#$00,#$9e,#$32,#$30,#$36,#$31,#$00,#$00,#$00
+
+    ; this is at (2061 dec)=($80d)
+    ; and it MUST be exactly after the above BASIC statement
+. = $80d
+    jmp $2800
+
+. = $1000
+    INCBIN "../bin/snake.pack"
+
+#if VERBOSE = 1
+    ECHO "PRG SIZE:",(. - $801 + 2),"=",[(. - $801 + 2)d]
+#endif
+