Added CAS support to the example game

14 files changed, 675 insertions, 59 deletions

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 6c232e7..3147c8b 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -14,6 +14,7 @@ compile:
   stage: build
   script:
     - make game
+    - make game-cas
 
 test:
   stage: test
diff --git a/CHANGES.md b/CHANGES.md
index 28436bc..421f4c8 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,5 +1,7 @@
 ## Release 1.1.12 - 2022-??-??
 
+ - Added CAS support to the example game, introducing new tools: `mkcas.py` and
+  `png2scr.py`.
  - Fix in `png2sprites.py` and `png2tiles.py`: ensure the order of the colours
   is always the same
 
diff --git a/Makefile b/Makefile
index e97a66c..b467286 100644
--- a/Makefile
+++ b/Makefile
@@ -8,6 +8,10 @@ game: bin libs
 	make -C tools
 	make -C game all
 
+game-cas: bin libs
+	make -C tools
+	make -C game cas
+
 test: game
 	make -C tests test
 
@@ -32,7 +36,7 @@ ap:
 bin/apultra: bin
 	make -C tools ../bin/apultra
 
-.PHONY: clean cleanall docs libs game
+.PHONY: clean cleanall docs libs game game-cas
 clean:
 	make -C src/ubox clean
 	make -C src/spman clean
diff --git a/README.md b/README.md
index dfbd8f3..301e856 100644
--- a/README.md
+++ b/README.md
@@ -80,6 +80,28 @@ An example game is included with the libraries and it can be built with:
 
 After a successful build, the game ROM should be in `./bin`.
 
+#### CAS support
+
+Although the focus is cartridge ROMs, CAS files (and audio) is still one of the
+cheapest ways of loading homebrew games on a real MSX.
+
+Optionally, is possible to generate a CAS file of the example game running:
+
+    make game-cas
+
+After a successful build, the game CAS should be in `./bin`.
+
+The CAS support has some limitations:
+
+ - It requires 32K of extra RAM.
+ - The compressed ROM must be less than 24576 bytes.
+ - The loader uses the BIOS, so it won't be fast.
+ - Machines with disk must have it disabled (by pressing shift on boot), to
+  have more memory available.
+
+Despite these limitations, it is worth considering releasing your game in CAS
+format as well as cartridge ROM.
+
 ### Building the docs
 
 The documentation is available at
diff --git a/TODO.md b/TODO.md
index cc75e31..e919fa8 100644
--- a/TODO.md
+++ b/TODO.md
@@ -3,7 +3,6 @@ Short/mid term:
  - Add util tools/libs (e.g. compression)
  - Improve MSX 1 support
  - Support 48K ROMs
- - CAS support
  - Some sort of cookie-cutter support to easily start new projects
 
 Long term:
diff --git a/docs/tools.md b/docs/tools.md
index 19705a7..67b797a 100644
--- a/docs/tools.md
+++ b/docs/tools.md
@@ -197,6 +197,38 @@ The entities are encoded in a stream that ends with the byte `0xff` as terminato
 
 Refer to the example game and `init_map_entities()` in `game.c` for a full example.
 
+### mkcas.py
+
+This is a simple tool to make CAS files to be used in different MSX emulators.
+
+It supports the following block types:
+
+ - binary: binary executable data, include loading and execution addresses.
+ - basic: tokenized BASIC code.
+ - ascii: ASCII text, can be BASIC for example. In case of BASIC code, the CR
+   LF is expected as end of line.
+ - custom-header: no block type, header with loading address and block length
+   followed by the data.
+ - custom: no block type, data stored "as-is".
+
+Use `-h` flag to get command line help, and check the example game for sample on
+how to build a CAS file with a loading screen.
+
+### png2scr.py
+
+This tools converts an PNG RGB image into a Screen 2 SCR image.
+
+The image is expected to use an approximation to RGB for the colours in the
+Toshiba palette (see `png2tiles.py` for the palette values).
+
+The image must be 256x192 pixels.
+
+The SCR file is 768 background tiles (6144 bytes) followed by the
+background colours for the 3 areas of the screen (6144 bytes), that can be
+uploaded to the VDP "as is".
+
+Check the example game for a sample on how to use it.
+
 ## Build helpers
 
 ### chksize
diff --git a/game/Makefile b/game/Makefile
index 3fe43f3..347d37b 100644
--- a/game/Makefile
+++ b/game/Makefile
@@ -6,6 +6,9 @@ all: generated bin build
 	cd src && ../../tools/mkdeps.py -b ../build -I ../generated:../../include ./ Makefile.deps
 	make -C src all
 
+cas: all
+	make -C src cas
+
 generated:
 	mkdir -p ./generated
 
@@ -18,7 +21,7 @@ build:
 openmsx: all
 	make -C src openmsx
 
-.PHONY: all clean default
+.PHONY: all cas clean default
 clean:
 	rm -rf ./generated ./bin ./build
 	make -C src clean
diff --git a/game/data/loading.png b/game/data/loading.png
new file mode 100644
index 0000000..ce196ef
--- /dev/null
+++ b/game/data/loading.png
diff --git a/game/src/Makefile b/game/src/Makefile
index b05ef4e..3ca267a 100644
--- a/game/src/Makefile
+++ b/game/src/Makefile
@@ -32,6 +32,9 @@ all: $(TMPDIR)/$(TARGET).rom
 	@$(CHKSIZE) $(ROM_MAX) 4000 $(TMPDIR)/$(TARGET).map
 	@cp $(TMPDIR)/$(TARGET).rom $(OUTDIR)
 
+cas: $(TMPDIR)/$(TARGET).cas
+	@cp $(TMPDIR)/$(TARGET).cas $(OUTDIR)
+
 openmsx: all
 	openmsx -carta $(OUTDIR)/$(TARGET).rom -machine msx1
 
@@ -51,10 +54,31 @@ $(TMPDIR)/$(TARGET).rom: $(OBJS) $(TMPDIR)/crt0.rel $(UBOX_LIBS)
 	hex2bin -e bin -p 00 -l $(ROM_MAX) $(TMPDIR)/$(TARGET).ihx
 	@cp $(TMPDIR)/$(TARGET).bin $(TMPDIR)/$(TARGET).rom
 
+LOADER_ADDR=0xe000
+LOADER_WORK_ADDR=0x8000
+$(TMPDIR)/$(TARGET).cas: $(TMPDIR)/$(TARGET).rom cas/loader.bas $(TMPDIR)/loader.bin $(TMPDIR)/loading.ap
+	apultra -v $(TMPDIR)/$(TARGET).rom $(TMPDIR)/$(TARGET).ap
+	../../tools/mkcas.py --name $(TARGET) $@ ascii cas/loader.bas
+	../../tools/mkcas.py -a --name loader --addr $(LOADER_ADDR) --exec $(LOADER_ADDR) $@ binary $(TMPDIR)/loader.bin
+	../../tools/mkcas.py -a --addr $(LOADER_WORK_ADDR) $@ custom-header $(TMPDIR)/loading.ap
+	../../tools/mkcas.py -a --addr $(LOADER_WORK_ADDR) $@ custom-header $(TMPDIR)/$(TARGET).ap
+
+$(TMPDIR)/loader.bin: $(TMPDIR)/loader.rel
+	$(CC) $(CFLAGS) $(LDFLAGS) --code-loc $(LOADER_ADDR) --data-loc 0 -lap $< -o $(TMPDIR)/loader.ihx
+	hex2bin -p 00 $(TMPDIR)/loader.ihx
+
+$(TMPDIR)/loading.ap: ../data/loading.png
+	../../tools/png2scr.py ../data/loading.png > $(TMPDIR)/loading.bin
+	apultra -v $(TMPDIR)/loading.bin $(TMPDIR)/loading.ap
+
+$(TMPDIR)/loader.rel: cas/loader.z80
+	$(AS) -g -o $@ $<
+
 clean:
 	rm -f $(TMPDIR)/*
 	rm -f $(OUTDIR)/$(TARGET).rom
+	rm -f $(OUTDIR)/$(TARGET).cas
 
-.PHONY: all clean
+.PHONY: all cas clean
 
 include Makefile.deps
diff --git a/game/src/cas/loader.bas b/game/src/cas/loader.bas
new file mode 100644
index 0000000..c94a478
--- /dev/null
+++ b/game/src/cas/loader.bas
@@ -0,0 +1 @@
+10 BLOAD"cas:",R

diff --git a/game/src/cas/loader.z80 b/game/src/cas/loader.z80
new file mode 100644
index 0000000..d7b058c
--- /dev/null
+++ b/game/src/cas/loader.z80
@@ -0,0 +1,219 @@
+;
+; TAPE LOADER USING THE BIOS
+;
+
+TAPION = 0x00e1
+TAPIN  = 0x00e4
+TAPIOF = 0x00e7
+DISSCR = 0x0041
+ENASCR = 0x0044
+LDIRVM = 0x005c
+CHGMOD = 0x005f
+CHGCLR = 0x0062
+FORCLR = 0xf3e9
+BAKCLR = 0xf3ea
+BDRCLR = 0xf3eb
+CHPUT  = 0x00a2
+TOTEXT = 0x00d2
+ENASLT = 0x0024
+RSLREG = 0x0138
+
+        .area _CODE
+        di
+        ; init the stack
+        ld sp, #0xf380
+
+        ; sslot fix
+        ld a, (0xffff)
+        cpl
+        and #0xf0
+        ld c, a
+        rrca
+        rrca
+        rrca
+        rrca
+        or c
+        ld (0xffff),a
+
+        in a, (#0xa8)
+
+        ; map RAM on 0x8000
+        and #0xcf
+        ld c, #16
+        ld hl, #0x8000
+        call select_ram
+
+        ; map RAM on 0x4000
+        and #0xf3
+        ld c, #4
+        ld hl, #0x4000
+        call select_ram
+
+        ei
+
+        ; now we have: ROM RAM RAM RAM
+
+        ; set these to black
+        ld a, #1
+        ld (FORCLR), a
+        ld (BAKCLR), a
+        ld (BDRCLR), a
+        call CHGCLR
+
+        ; load the loading screen
+        call load_custom_block
+
+        ld hl, (block_addr)
+        ld de, #0x4000
+        call ap_uncompress
+
+        call upload_screen
+
+        ; load the code
+        call load_custom_block
+
+        ld hl, (block_addr)
+        ld de, #0x4000
+        call ap_uncompress
+
+        ; cas main
+        jp 0x4010
+
+upload_screen:
+        ld a, #2
+        call CHGMOD
+
+        call DISSCR
+
+        ld hl, #0x4000
+        ld de, #0
+        ld bc, #256 * 8
+        call LDIRVM
+
+        ld hl, #0x4000 + 256 * 8
+        ld de, #256 * 8
+        ld bc, #256 * 8
+        call LDIRVM
+
+        ld hl, #0x4000 + 256 * 8 * 2
+        ld de, #256 * 8 * 2
+        ld bc, #256 * 8
+        call LDIRVM
+
+        ld hl, #0x4000 + 256 * 8 * 3
+        ld de, #0x2000
+        ld bc, #256 * 8
+        call LDIRVM
+
+        ld hl, #0x4000 + 256 * 8 * 4
+        ld de, #0x2000 + 256 * 8
+        ld bc, #256 * 8
+        call LDIRVM
+
+        ld hl, #0x4000 + 256 * 8 * 5
+        ld de, #0x2000 + 256 * 8 * 2
+        ld bc, #256 * 8
+        call LDIRVM
+
+        jp ENASCR
+
+load_custom_block:
+        call TAPION
+        jp c, tape_error
+
+        ld bc, #4
+        ld hl, #block_addr
+        call load_block
+
+        ld bc, (block_len)
+        ld hl, (block_addr)
+        call load_block
+
+        jp TAPIOF
+
+load_block:
+        ld a, r
+        and #15
+        out (#0x99), a
+        ld a, #0x87
+        nop
+        nop
+        out (#0x99), a
+
+        push bc
+        push hl
+        call TAPIN
+        pop hl
+        pop bc
+        jr c, tape_error
+
+        ld (hl), a
+        inc hl
+
+        dec bc
+        ld a, b
+        or c
+        jr nz, load_block
+
+        ld a, #1
+        out (#0x99), a
+        ld a, #0x87
+        nop
+        nop
+        out (#0x99), a
+        ret
+
+select_ram:
+        ld b, #4
+select_ram_loop:
+        out (#0xa8), a
+        ld (hl), a
+        cp (hl)
+        ret z
+        add a, c
+        djnz select_ram_loop
+
+memory_error:
+        ld hl, #mem_err_message
+        jp display_error
+
+tape_error:
+        ld hl, #tape_err_message
+
+display_error:
+        push hl
+        call TOTEXT
+
+        ld a, #1
+        ld (BAKCLR), a
+        ld (BDRCLR), a
+        ld a, #6
+        ld (FORCLR), a
+        call CHGCLR
+
+        pop hl
+print_loop:
+        ld a, (hl)
+        or a
+        jr z, halt0
+        inc hl
+        call CHPUT
+        jr print_loop
+halt0:
+        halt
+        jr halt0
+
+tape_err_message:
+        .str "TAPE READ ERROR"
+        .db 0
+mem_err_message:
+        .str "MEMORY INIT ERROR"
+        .db 0
+
+        .area _DATA
+
+block_addr:
+        .dw 2
+block_len:
+        .dw 2
+
diff --git a/game/src/crt0.z80 b/game/src/crt0.z80
index 81763d0..c8bd167 100644
--- a/game/src/crt0.z80
+++ b/game/src/crt0.z80
@@ -1,82 +1,87 @@
 .module crt0
-.globl	_main
 
-.area	_HOME
-.area	_CODE
-.area	_INITIALIZER
+.globl  _main
+
+.area   _HOME
+.area   _CODE
+.area   _INITIALIZER
 .area   _GSINIT
 .area   _GSFINAL
 
-.area	_DATA
-.area	_INITIALIZED
-.area	_BSEG
+.area   _DATA
+.area   _INITIALIZED
+.area   _BSEG
 .area   _BSS
 .area   _HEAP
 
-.area   _CODE
-
 ENASLT = 0x0024
 RSLREG = 0x0138
 CLIKSW = 0xf3db
 
-	; ROM header
-	.str "AB"
-	.dw _main_init
-	.db 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+.area   _CODE
+        ; ROM header
+        .str "AB"
+        .dw _main_init
+        .db 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
+
+        ; entry point skipping the init code that is used
+        ; when starting from cassette
+        jp _cas_main
 
 _main_init::
 
-	; init the stack
-	di
-	ld sp, #0xf380
-	ei
+        ; init the stack
+        di
+        ld sp, #0xf380
+        ei
 
-	; setup memory
-	; ref: https://www.msx.org/forum/msx-talk/development/memory-pages-again
+        ; setup memory
+        ; ref: https://www.msx.org/forum/msx-talk/development/memory-pages-again
 
-	call RSLREG
-	rrca
-	rrca
-	and #3
-	ld c, a
-	add a, #0xc1
-	ld l, a
-	ld h, #0xfc
-	ld a, (hl)
-	and #0x80
-	or c
-	ld c, a
-	inc l
-	inc l
-	inc l
-	inc l
-	ld a, (hl)
-	and #0x0c
-	or c
-	ld h, #0x80
-	call ENASLT
+        call RSLREG
+        rrca
+        rrca
+        and #3
+        ld c, a
+        add a, #0xc1
+        ld l, a
+        ld h, #0xfc
+        ld a, (hl)
+        and #0x80
+        or c
+        ld c, a
+        inc l
+        inc l
+        inc l
+        inc l
+        ld a, (hl)
+        and #0x0c
+        or c
+        ld h, #0x80
+        call ENASLT
 
-	; disable key click sound
-	xor a
-	ld (CLIKSW), a
+_cas_main::
+        ; disable key click sound
+        xor a
+        ld (CLIKSW), a
 
-	call gsinit
-	call _main
+        call gsinit
+        call _main
 
 halt0:
-	halt
-	jr halt0
+        halt
+        jr halt0
 
 .area   _GSINIT
 gsinit::
-	ld bc, #l__INITIALIZER
-	ld a, b
-	or a, c
-	jr Z, gsinit_next
-	ld de, #s__INITIALIZED
-	ld hl, #s__INITIALIZER
-	ldir
+        ld bc, #l__INITIALIZER
+        ld a, b
+        or a, c
+        jr Z, gsinit_next
+        ld de, #s__INITIALIZED
+        ld hl, #s__INITIALIZER
+        ldir
 gsinit_next:
 
 .area   _GSFINAL
-	ret
+        ret
diff --git a/tools/mkcas.py b/tools/mkcas.py
new file mode 100755
index 0000000..267270d
--- /dev/null
+++ b/tools/mkcas.py
@@ -0,0 +1,164 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2020-2022 by Juan J. Martinez <jjm@usebox.net>
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
+__version__ = "1.1"
+
+import os
+from argparse import ArgumentParser
+
+DEF_ADDR = 0x4000
+TYPES = ("binary", "basic", "ascii", "custom-header", "custom")
+TYPE_BLOCK = {
+    "binary": bytes((0xD0 for _ in range(10))),
+    "basic": bytes((0xD3 for _ in range(10))),
+    "ascii": bytes((0xEA for _ in range(10))),
+}
+
+BLOCK_ID = bytes((0x1F, 0xA6, 0xDE, 0xBA, 0xCC, 0x13, 0x7D, 0x74))
+
+
+def write_word(fd, word):
+    fd.write(bytes((word & 0xFF, word >> 8)))
+
+
+def auto_int(value):
+    return int(value, 0)
+
+
+def main():
+
+    parser = ArgumentParser(
+        description="Make a CAS file for the MSX",
+        epilog="Copyright (C) 2020-2022 Juan J Martinez <jjm@usebox.net>",
+    )
+
+    parser.add_argument(
+        "--version", action="version", version="%(prog)s " + __version__
+    )
+    parser.add_argument(
+        "-a",
+        "--add",
+        dest="add",
+        action="store_true",
+        help="append to the existing CAS file instead of creating a new one",
+    )
+    parser.add_argument(
+        "--name",
+        dest="name",
+        default=None,
+        type=str,
+        help="name to use for the file (limit 6 chars, defaults to the file name)",
+    )
+    parser.add_argument(
+        "--addr",
+        dest="addr",
+        default=DEF_ADDR,
+        type=auto_int,
+        help="address to load if binary file (default: 0x%04x)" % DEF_ADDR,
+    )
+    parser.add_argument(
+        "--exec",
+        dest="exec",
+        default=DEF_ADDR,
+        type=auto_int,
+        help="address to exec if binary file (default: 0x%04x)" % DEF_ADDR,
+    )
+
+    parser.add_argument("output", help="target .CAS file")
+    parser.add_argument("type", help="file type", choices=TYPES)
+    parser.add_argument("file", help="input file")
+
+    args = parser.parse_args()
+
+    if args.add:
+        flags = "ab"
+    else:
+        flags = "wb"
+
+    with open(args.output, flags) as out:
+
+        if args.name:
+            name = args.name
+        else:
+            name = os.path.basename(args.file)
+
+        with open(args.file, "rb") as inf:
+            data = inf.read()
+
+        out.write(BLOCK_ID)
+
+        if args.type == "ascii":
+
+            out.write(TYPE_BLOCK[args.type])
+            out.write(name[:6].ljust(6).encode("ascii"))
+
+            for b in range(0, len(data), 256):
+                out.write(BLOCK_ID)
+                out.write(data[b : b + 256])
+
+            padding = 256 - (len(data) % 256)
+            if padding == 256:
+                out.write(BLOCK_ID)
+            out.write(bytes((0x1A for _ in range(padding))))
+
+        elif args.type == "basic":
+
+            out.write(TYPE_BLOCK[args.type])
+            out.write(name[:6].ljust(6).encode("ascii"))
+            out.write(BLOCK_ID)
+            out.write(data)
+
+        elif args.type == "binary":
+
+            addr = args.addr
+            exec_addr = args.exec
+            end_addr = addr + len(data) - 1
+
+            if end_addr > 0xFFFF:
+                parser.error("Binary doesn't fit in memory")
+
+            out.write(TYPE_BLOCK[args.type])
+            out.write(name[:6].ljust(6).encode("ascii"))
+
+            out.write(BLOCK_ID)
+            write_word(out, addr)
+            write_word(out, end_addr)
+            write_word(out, exec_addr)
+
+            out.write(data)
+
+        elif args.type == "custom-header":
+
+            addr = args.addr
+            length = len(data)
+
+            write_word(out, addr)
+            write_word(out, length)
+            out.write(data)
+
+        else:
+            # custom
+            out.write(data)
+
+
+if __name__ == "__main__":
+    main()
diff --git a/tools/png2scr.py b/tools/png2scr.py
new file mode 100755
index 0000000..5d08915
--- /dev/null
+++ b/tools/png2scr.py
@@ -0,0 +1,140 @@
+#!/usr/bin/env python3
+#
+# Copyright (C) 2018-2022 by Juan J. Martinez <jjm@usebox.net>
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
+
+__version__ = "1.0"
+
+import sys
+from argparse import ArgumentParser
+from PIL import Image
+from collections import defaultdict
+
+DEF_W = 8
+DEF_H = 8
+
+# TOSHIBA palette
+MSX_COLS = [
+    (255, 0, 255),
+    (0, 0, 0),
+    (102, 204, 102),
+    (136, 238, 136),
+    (68, 68, 221),
+    (119, 119, 255),
+    (187, 85, 85),
+    (119, 221, 221),
+    (221, 102, 102),
+    (255, 119, 119),
+    (204, 204, 85),
+    (238, 238, 136),
+    (85, 170, 85),
+    (187, 85, 187),
+    (204, 204, 204),
+    (238, 238, 238),
+]
+
+
+def main():
+
+    parser = ArgumentParser(
+        description="PNG to SCR file",
+        epilog="Copyright (C) 2018-2022 Juan J Martinez <jjm@usebox.net>",
+    )
+
+    parser.add_argument(
+        "--version", action="version", version="%(prog)s " + __version__
+    )
+
+    parser.add_argument("image", help="image to convert")
+
+    args = parser.parse_args()
+
+    try:
+        image = Image.open(args.image)
+    except IOError:
+        parser.error("failed to open the image")
+
+    if image.mode != "RGB":
+        parser.error("not a RGB image")
+
+    (w, h) = image.size
+
+    if w % 256 or h % 192:
+        parser.error("%s size is not 256x192" % args.image)
+
+    data = image.getdata()
+
+    color_idx = defaultdict(list)
+    color = []
+    out = []
+    ntiles = 0
+    for y in range(0, h, DEF_H):
+        for x in range(0, w, DEF_W):
+            # tile data
+            tile = [
+                data[x + i + ((y + j) * w)] for j in range(DEF_H) for i in range(DEF_W)
+            ]
+
+            # get the attibutes of the tile
+            # FIXME: this may not be right
+            for i in range(0, len(tile), DEF_W):
+                cols = list(sorted(set(tile[i : i + DEF_W])))
+
+                if len(cols) > 2:
+                    parser.error(
+                        "tile %d (%d, %d) has more than two colors: %r"
+                        % (ntiles, x, y, cols)
+                    )
+                elif len(cols) == 1:
+                    cols.append(MSX_COLS[1])
+
+                for c in cols:
+                    if c not in MSX_COLS:
+                        parser.error(
+                            "tile %d (%d, %d) has a color not in the MSX palette: %r"
+                            % (ntiles, x, y, c)
+                        )
+
+                # each tile has two coloributes per row
+                color_idx[ntiles * DEF_H + i // DEF_W] = cols
+                color.append((MSX_COLS.index(cols[1]) << 4) | MSX_COLS.index(cols[0]))
+
+            frame = []
+            for i in range(0, len(tile), 8):
+                byte = 0
+                p = 7
+                for k in range(8):
+                    # 0 or 1 is determined by the order in the coloributes for that row
+                    byte |= (
+                        color_idx[ntiles * DEF_H + i // DEF_W].index(tile[i + k]) << p
+                    )
+                    p -= 1
+
+                frame.append(byte)
+            ntiles += 1
+            out.extend(frame)
+
+    sys.stdout.buffer.write(bytes(out))
+    sys.stdout.buffer.write(bytes(color))
+
+
+if __name__ == "__main__":
+    main()