View source for Amstrad CPC

== Amstrad CPC ==
The Amstrad consists of a Z80A @ 3.5 MHz CPU 

=== Setting up ===


* Native-assemblers:
** [http://orgams.wikidot.com/ orgams] - Definitvely the state-of-the-art assembler on Amstrad CPC

* Cross-Assemblers:
** The emulator [http://www.winape.net/ Winape] has an integrated [http://www.winape.net/help/assembler.html assembler].
** cross-platform [https://github.com/z00m128/sjasmplus/releases/latest SjASMPlus] assembler supports CPC snapshot and CDT files since v1.18.4.
** [https://github.com/EdouardBERGE/rasm/releases/latest Rasm] - extremely fast cross-platform Z80 assembler with many features.
** [https://cpcsdk.github.io/rust.cpclib/basm/ BASM] - a modern Z80 assembler with many features borrowed to mainstream spectrum assemblers, maxam and rasm.

* Emulator(s): 
** [http://www.winape.net/ Winape] is very accurate and includes an assembler / debugger
** [https://www.cpc-power.com/cpcarchives/index.php?page=articles&num=445 Caprice] gets very regular updates
** [http://cngsoft.no-ip.org/cpcec.htm CPCEC] is very fast
** [https://sourceforge.net/projects/javacpc/ JavaCPC] offers many features
** [https://www.retrovirtualmachine.org/ Retro Virtual Machine] is visually very impressive
** [http://www.roudoudou.com/ACE-DL/ Ace-DL] one of the most accurate emulators / UI is less ergonomic than Winape ATM, but it will improve with time
** [https://www.amspirit.fr/ Amspirit] another accurate emulator

=== Video Display ===
No information yet

=== Sound ===
No information yet


=== Assumed state at start ===

If the intro is launched with RUN"intro, we can assume those facts

* CRTC R12/R13 = 0x3000
* 0xC000-0xFFFF is filled with byte 0x00
* screen mode is 1


=== On the use of Amsdos Header ===

In most competition, Amsdos header counts in the size of the binary. So 128 bytes are lost by definition.
However, there are two small areas that are not used and can embed data !
They are at position 0x1c (36 bytes) and 0x45 (59 bytes) https://www.cpcwiki.eu/index.php?title=AMSDOS_Header.

In some conditions we can access them :

- If the file (header included) is smaller than 2048-128 bytes, the header is available at address (0xBE7D) + 0xe4 (i.e. 0xbe7d contains an address and 0xe4 bytes later, you have the header). You have access to the two areas
- Otherwise, the BEGINNING of the header is available at address (0xBE7D) + 0x55, and you only have access to the 36 bytes at 0x1c relative position 



=== Additional Resources ===
* 64 NOPs Amstrad CPC Tech Blog - https://64nops.wordpress.com/