Changes

Speccy Port

37 bytes added, 18:41, 13 December 2023
It is worth noting that Spectrum ports also existed on [[MSX]], [[Enterprise]] 64/128, [[SAM Coupé]] and non-[[Z80]] [[Thomson]] MO/TO, [[Commodore 64|C64]].
==List of Spectrum Ports==
[[List of Speccy Ports]]
==How these should have looked==
This (the larger border) led to the false argument that the CPC's resolution was inferior to the Spectrum one although the amount of pixels on the screen is EXACTLY the same.
====Double buffering==== TODO: ==Screen dimensions===
By setting CRTC register settings the Amstrad's screen dimensions can be reprogrammed to match the Spectrum's.
* For a smaller screen less memory is used for the screen (16KB vs 12K). The memory used by the screen is the same regardless of CPC mode used. Unused areas can be used to store graphics, code and music. For a CPC screen at &c000, the unused areas are: c600-c7ff, ce00-cfff, d600-d7ff, de00-dfff, e600-e7ff, ee00-efff, f600-f7ff, fe00-ffff
====Random numbers====
Sometimes Spectrum games generate random numbers by reading from the Spectrum's ROM which is always readable in the memory range &0000-&3fff.
Where possible the Spectrum and Amstrad versions should use the same random number generation based on a stored seed.
====Double buffering==== TODO: ====Memory arrangement====
Spectrum game's often use the memory from &5500-&ffff.
- If you are not using a custom disc or tape loader then during loading you will need to preserve the firmware memory regions. The easiest thing to do is start the game lower in memory (&0040), use the default screen at &c000-&ffff, and then once loaded copy data over these areas (provided you are not doing furthur loading/saving).
 ====Original consequences (under construction)====
The Amstrad CPC was one of the best 8-bit computers of its time in terms of graphical capabilities. But those advanced capabilities had an impact on CPU resources.
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