On 3/18/2020 6:31 AM, Swap Jim via Freedos-user wrote:
FreeDOS is very, very slow on QEMU running in a Raspberry 4.
It's drawing the screen line by line when I do a DIR on C:\, with only
7 directories and files in it. It's worse in full screen.
For those of you that run FreeDOS on a Raspberry, can you offer a tip
to make it go faster?
Here is some more info.
It's a Raspberry Pi 4 B+ with 4GB of RAM. I'm running the latest
Raspbian. I couldn't manage to install QEMU from apt, so I've compiled
version 4.2.0 with these flags:
./configure --target-list=i386-softmmu --disable-vnc --enable-sdl
make 'CFLAGS=-Wall -g -O2 -w'
That is a problem of QEMU, not FreeDOS.
What some people are forgetting (had the exact kind of discussion in a
vintage computer forum just a few days ago) is that in this case, QEMU
needs to completely emulate an x86 CISC CPU on an ARM RISC CPU,
including converting all data on the fly between little-endian and
big-endian format on the fly, all the time.
This is a complete different situation for example than emulating a
16bit x86 PC system on a 64bit x86 host system, like running DOSBox or
VirtualBox. While the later doesn't (in 64bit mode) support 16bit
operation anymore, it is still the same basic underlying CPU
architecture, and the same data "endian-ness".
Ralf
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