Programming:Cross Development

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 wich 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 wich 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.

Tools needed for cross development

Linux

Cross assemblers

• SjasmPlus
• sjasm
• Zasm [1]
• ZMac

Disassemblers

• dzasm [2]

Disc management

• CPCTools
• iDSK / Cpcfs / Cpcxfs
• dsktools

Tape management

• 2cdt [3]
• cdtcheck [4]
• cdttst [5]
• samp2 [6]

Cartidge management

• buildcpr [7]

Editing

• Vim

Crunching

• Exomizer
• pucrunch [8]

Emulators

• Arnold
• Caprice [9]
• cpcemu [10]
• xcpc [11]

Usefull scripts

Supress 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 similars fonctionnalities 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

Windows

Cross Assemblers

• tasm
• Pasmo
• ZMac
• zasm
• WinApe's built in assembler

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