16.Dec.2022
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Emulator: QEMU 7.2.0 released
QEMU is an open source computer emulator and virtualizer. QEMU is able to emulate a complete computer in software without the need of hardware virtualization. So it is possible to emulate Amiga operating systems like AROS, AmigaOS or MorphOS on QEMU. This support is provided by QEMU developer Zoltan Balaton, who gives lots of tips and info on a dedicated webseite (see also our Excursion of Amiga operating systems on non-native hardware).
According to Zoltan Balaton, the now released version 7.2.0 (PowerPC related commits) contains some changes that mainly affect newer Power CPUs, but also those that affect the entire PPC emulation: for example, the command decoding has been changed to decodetree. This is a generic method of describing commands, using general code for decoding instead of the custom code used before. As the developer kindly explained to us, this can lead to better performance, but it does not have to, as Decodetree is not optimised.
Similarly, there were also some changes to the implementation of AltiVec commands that could improve their speed, but it would depend on how it was used and what the host CPU supported. He had done some tests and found that in some cases it could be a few percent faster, but it did not really make a big change. Since sam460ex does not have AltiVec, it only benefits from the PPC instruction decoding changes, he said. Emulation via pegasos2 and mac99 could be slightly better with code that uses AltiVec. However, he says it is difficult to test this with AmigaOS 4, which has no graphics driver for the graphics cards emulated by QEMU in the pegasos2 version. For tinkerers, however, he has an idea that could be tried out:
One would have to copy some drivers to get the output on pegasos2. This means that one has to edit the boot CD or an installed version (which is not so easy, but feasible). You would have to copy the kernel from the AmigaOS-pegasos2 version and update the PCIGraphics.card and siliconmotion502.chip from the sam460ex version, as he erwähnt before. You would then have to create a CD from this. (dr)
[News message: 16. Dec. 2022, 06:08] [Comments: 0]
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