Programming:Cross Development
Contents
Introduction
Cross development is a development method where you use another machine (the host) to develop programs for the CPC (target). This is interesting because you can make a big program which sourcecode does not even fit on the CPC ram.
The main drawback is that transferring the compiled code to the CPC can be quite difficult. But there are pretty good emulators which you can use for testing.
Once you have your binary file you have two choices depending on if the game will be for cassette or disc.
- Atari ST was a common 16 bit computer actually used in cross development of games on CPC.
Of course nowadays cross development use far more powerful modern computers.
- ZX Spectrum was also a source of cross development...er... let's better say Gross Development indeed.
Tools needed for cross development
Integrated toolchains
An integrated cross-development toolchain is a time saver for development as it automates all necessary steps from a full set of source materials (source code, graphics, music, parameters in whatever format is practical for editing, etc) to one or several formats ready to run on the target machines. It also sometimes includes automatically launching or notifying an emulator or target device. See e.g. Build Automation on wikipedia.
Such a design has several advantage:
- allows the usage of any text/graphic editor of modern platforms
- you can change anything in one or more source files and you get an updated build quickly without error-prone manual steps
- allows arbitrary transform or generation of intermediary files (code or data).
- makes easy to have specific builds (e.g. for automated tests like to check if a different compiler produces correct code, variant build for slightly different targets)
- since most material are text files or small independent files, it benefits hugely from modern tools for revision control like Git which makes sharing and merging code between developers much easier, increasing the time saved.
An ideal toolchain does not force its user into specific ways of doing things but is flexible enough to let the user adjust for whatever specific needs (use different languages, compilers, linkers, etc). Along with a properly designed and structured source tree, this makes projects less dependent on specific tools used to build them, and be more resilient to bit rot due to software build environment change.
Please note that an integrated toolchain has little to do with anything visible on-screen. A good toolchain can be triggered by most flexible enough graphical environments and generally produces a text log of the work done. Nevertheless, the concept of toolchains is more natural to Linux/Unix way of thinking/doing things, and those environments are already full of reusable and combinable tools that ease the creation and maintenance of a toolchain. Windows users can generally use tools developed for Unix through the cygwin software adaptation layer but running a Linux distribution in a virtual machine may be more practical.
There are some attempts at creating toolchains targeting the CPC:
- Not an integrated toolchain, but a collection of tools that can be strung together to make one. Currently active (as of end of 2012): on CPC SDK for Linux/Unix PlukoMandy mentions http://code.google.com/p/cpcsdk
- 2012-11-12 Recommended Linux cross-dev tool chain? mentions a makefile-based toolchain targeting dsk images or tapes
- 2011-11-18 cpc-dev-tool-chain an embryo of an integrated C or ASM development toolchain for the Amstrad CPC platform (or emulator). Designed for quick start on Linux (or similar) systems : get a copy, run "make" and get a DSK ready to run into the emulator. It even downloads and compiles tools (the cross-compiler, iDSK) if needed.
- 2009-06-16 My new cross-development kit explain what is basically a toolchain but link is broken as of 2013-01-08
Linux
Cartridge management
Cross assemblers
Crunching
Disassemblers
Disc management
Editing
- scite
- pico
- xemacs
- Vim
Emulators
Tape management
Toolkits
Useful scripts
Suppress header information of a file
cat file_with_header | tail -c+129 > file_without_header
Needed Tools
These tools have to not require a lot of requirement and most of them must work in command line without GUI. This will allow to use them with Makefile scripts. They have to be fast too, it will be disappointing to wait more when doing CrossDev than when doing code on a real CPC. A good thing (like most of CPCTools) is to have a portable code which compile on most platforms.
- a good emulator which can be integrated in other tools. (Ramlaid first try to change Caprice is a good start)
- an integration of Ramlaid's tools with Nautilus
- ameliorations of Caprice in order to have similar functionalities than WinApe (disasm, asm, ...)
- debug the libdsk which seems to work very bad on actual computers (writting fail a lot)
- a lot of macros, or libraries for SJASMPlus shared by people in order to share code
- share a generic Makefile able to be use for build CPC project
- a lot of little command line utilities (could be add to CPCTools ?) really well done :
- graphics tools :
- convert images from PC to CPC, or CPC to PC (cf. tools based on ImageMagick or GD)
- equivalent of Anoine's FontCatcher
- 2 tools which work with BASIC :
- one for create BASIC AMSDOS files from ASCII or UTF-8 text files
- one for create ASCII or UTF-8 text files from BASIC AMSDOS files
- (this can already be done with manageDSK for files inside a DSK, maybe extract the code from there)
- data manipulation tools :
- ability to arrange data files for example modify bytes order in a picture file by using Gray code capabilities for changing line with modifying 1 bit
- graphics tools :
Windows
Cross Assemblers
Cross compilers (C)
For tutorial, see http://www.cpcmania.com/Docs/Programming/Programming.htm by Mochilote
- Z88DK
- SDCC, notably SDCC and CPC had hints and practical examples about the principles of writing in C for CPC.
- PhrozenC
Graphics
- AMSprite - Sprite/Loading Screen Editor and graphics conversion tools
Sound
- WYZTracker - Music tracker / Sound effects editor
- Vortex Tracker
Testing on a real CPC
For cassette
- 2CDT to add the files to a Cassette Image File (CDT)
- Tape2WAV to convert the Cassette Image file (CDT) into a WAV file.
- Then you can run the program on the emulator the same way as you would run it on a real CPC, or
- Connect your CPC (CPC664 and CPC6128 have a cassette input) to the Line-Out output of your PC soundcard
- On the CPC type:
|TAPE:RUN"
- Start your WAV player
- Set the volume to maximum
- play the WAV file
- Wait for the program to load...
For disc
- Use CPCFS or CPCXFS to put the binary files into a Disk Image file (DSK)
- Then you can run the program on the emulator the same way as you would run it on a real CPC
If your CPC has a 3.5" disc drive then the easiest method is to transfer the DSK to a 3.5" disc using the PC.
- Then use CPCDiskXP to write the DSK to a 3.5" disc drive - Put the disc into your CPC's 3.5" disc drive and type - |B: RUN "<gamename>
Snapshots
The fastest way of testing your code on an emulator is by creating a snapshot. Use CPCSnapshot to insert your assembled code into a snapshot file. Then just load the snapshot file into the emulator. Windows users may also try WinAPE's integrated assembler which assembles the code directly into the emulated CPC's memory.
Web links
- CPC Cross Development tools by Ramlaid (Link broken as 2012-01-08. If you can help, please update.)
