FloatFFD - redcode/ZXSpectrum GitHub Wiki

Author: Woodmass, Mark

Release date Links Download
2023-02-28 Discord post zip (hosted) - zip (Discord post)
2018-02-24 (unreleased, provided by the author) Discord post tap (hosted) - zip (Discord post)

Description

FloatFFD tests HAL bug on 128K/+2 Spectrums described in Sinclair wiki:

Reads from port 0x7ffd cause a crash, as the 128's HAL10H8 chip does not distinguish between reads and writes to this port, resulting in a floating data bus being used to set the paging registers.

Note that this bug appears on 128K/+2 only, it does not appear on +2A/+3.

Expected results

Spectrum 128K, Spectrum +2:
FloatFFD_128K_expected

Copyright © Manuel Sainz de Baranda y Goñi, Peter Helcmanovsky, holub, Weiv and Zoran Vučenović
Published under the terms of the GNU Free Documentation License

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