Re: [hatari-devel] Hatari WinUAE vs oldUAE information, and MiNT with MMU?

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Le 09/01/2021 à 16:58, Eero Tamminen a écrit :

> Nicolas:
>
> * There are still 2 demos that work only with
>    oldAUE core.
>
>    Fit's "Hex Pistols" and "Stercus Accidit" Falcon
>    demos bomb at startup regardless of what Hatari
>    WinUAE CPU core options are used, although they
>    work fine with oldUAE CPU core, both with
>    "--compatible" option enabled and disabled,
>    and with TOS4 and EmuTOS.
>
>    Could you check that it's not some long term
>    regression, but e.g. due to cycle-accuracy
>    reasons?

Hi

this is not a regression, nor some cycle accuracy issue, but some FPU 
changes.
In old UAE, all FPU opcodes were more or less allowed for all fpu model.
But in recent WinUae, toni fixed a lot of them to give the correct 
exception when not implemented on some fpu.

For hex pistol, programs require a 68040 or 68060 with fpu set to 
internal, not 6888x (as FPU is always internal in 68040/60, maybe we 
should forbid using anything else and always force fpu 'internal' for 
these 2 cpu)

if using 6888x, you get this error :
cpu video_cyc=  9191 999@  8 : 000232F6 f200 0144 
FDMOVE.X FP0,FP2 (68040+)
cpu exception 11 vector 2c currpc 232f6 buspc 232f6 newpc e00fb6 
fault_e3 0 op_e3 0 addr_e3 0 SR 300
-> FDMOVE is 68040/60 only

when using 68040+fpu internal, we get this error later (using log-level 
debug) :
DEBUG: FPU unimplemented instruction: OP=F200-0903 
SRC=00000000-00000000-00000000 EA=00000000 PC=00022BE6
DEBUG: FPU UNIMPLEMENTED INSTRUCTION/FPU DISABLED EXCEPTION PC=00022bea
f200 0903 is fintrz.x  fp2
which doesn't exist for 68040 according to WinUAE's source, Motorola's 
doc tells it requires software emulation
So, program crash with illegal instruction in 68040 mode

when using 68060+fpu internal; we get this error :
DEBUG: 68060 unimplemented opcode 4C3A, PC=001d3a96
$001d3a96 : 4c3a 0405 1018                     mulu.l    $1d4ab2(pc),d0,d5
but in that case the program seems to continue anyway, it then waits for 
some MFP events, I didn't look what exactly so far.

So program seems to only run with 68060+fpu internal, compatibility 
notes should be updated.


stercus :

similar fpu issues, except this time the demo uses the FCOS opcode, 
which doesn't exist on 68040/60

DEBUG: CPU=68040, FPU=68040 (host 64b), MMU=0, JIT=0.
DEBUG: FPU unimplemented instruction: OP=F200-110E 
SRC=3FFA0000-E5C8F9DD-DD0A0000 EA=00000000 PC=00021C2E
DEBUG: FPU UNIMPLEMENTED INSTRUCTION/FPU DISABLED EXCEPTION PC=00021c32
$00021c32 : f200 131d                          fcos.x    fp4,fp6

DEBUG: CPU=68060, FPU=68060 (host 64b), MMU=0, JIT=0.
DEBUG: FPU unimplemented instruction: OP=F200-110E 
SRC=00000000-00000000-00000000 EA=00000000 PC=00021C2E
DEBUG: FPU UNIMPLEMENTED INSTRUCTION/FPU DISABLED EXCEPTION PC=00021c32
$00021c32 : f200 131d                          fcos.x    fp4,fp6

So, demo requires a 68030 + 68882 I guess, it won't work with 68040/60. 
but it seems to fail anyway, there might be other issues later, maybe 
not fpu related.

Nicolas