Hervé Poussineau wrote:
> Hi,
>
> This patch uses the new "-cpu" command line option, to choose the CPU at
> runtime (R4Kc/R4Kp and FPU/no FPU)
> The model can be extended to emulate more accurately some CPUs.
>
> This removes the MIPS_USES_FPU compilation time option, and replaces by a
> runtime one.
>
> Please comment.
Looks very nice, except that the CPU models are out of touch with reality. :-)
- There is no CPU called "R4Kc" etc.
- What Qemu emulates is currently close to a 4KEc with an R3000-style
FPU attached. (A 4KEc is a 4Kc with MIPS32R2 instructions.)
- MIPS Technologies "4Kc" and "4Kp" have both no FPU support at all,
they are also 32bit only. (IIRC the difference those two is that
the 4Kp has only a fixed mapping MMU, the 4Kc has the real thing.)
- For a Jazz/Magnum-like CPU we should add a "R4000" or probably
a "R4400". This CPU is 64bit and has always a FPU.
- For the Malta I plan to go for a 34Kf, but that lacks a few bits for
now.
So, to make some sense out of it:
- Qemu "4kc" machine, 32bit, no FPU: 4Kc or 4KEc
- Qemu "4kc" machine, 32bit, with FPU: 24Kf
- Qemu "4kc" machine, 64bit, with FPU: R4000, this should become a
separate machine.
- MIPS Malta, 32bit, no FPU: 4KEc
- MIPS Malta, 32bit, with FPU: 24Kf
Does this sound reasonable?
Thiemo
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