Re: [Qemu-devel] [PATCH v4] m68k: implement movep instruction

[Laurent Vivier]

Le 06/02/2018 à 14:30, Pavel Dovgalyuk a écrit :
>> From: Laurent Vivier [mailto:address@hidden
>> Le 06/02/2018 à 13:44, Pavel Dovgalyuk a écrit :
>>> This patch implements movep instruction. It moves data between a data 
>>> register
>>> and alternate bytes within the address space starting at the location
>>> specified and incrementing by two.
>>>
>>> It was designed for the original 68000 and used in firmwares for
>>> interfacing the 8-bit peripherals through the 16-bit data bus.
>>
>> Did you test this change with some kind of firmware?
> 
> Yes, we implemented this instruction when tried to emulate Macintosh-128k on 
> Qemu.
> 
>>> Without this patch opcode for this instruction is recognized as some bitop.
>>>
>>> Signed-off-by: Pavel Dovgalyuk <address@hidden>
>>> Signed-off-by: Mihail Abakumov <address@hidden>
>>>
>>> --
>>>
>>> v4: - fixed offset calculation misprint
>>>
>>> v3: - simplified movep function code
>>>     - joined movep masks
>>>
>>> v2: - disabled movep for Coldfire
>>>     - fixed gen_store/load usage
>>> ---
>>>  target/m68k/cpu.c       |    2 ++
>>>  target/m68k/cpu.h       |    1 +
>>>  target/m68k/translate.c |   46 
>>> ++++++++++++++++++++++++++++++++++++++++++++++
>>>  3 files changed, 49 insertions(+)
>>
>> Tested-by: Laurent Vivier <address@hidden>
>>
>> I've checked we have the same result on a real 68040
>>
>> Reviewed-by: Laurent Vivier <address@hidden>
> 
> Thanks!
> 
> By the way, we also handled reset interrupt, but it is not compatible with 
> other m68k platforms:
> 
> @@ -66,8 +66,9 @@ static void m68k_cpu_reset(CPUState *s)
>      cpu_m68k_set_fpcr(env, 0);
>      env->fpsr = 0;
>  
> -    /* TODO: We should set PC from the interrupt vector.  */
> -    env->pc = 0;
> +    env->vbr = 0;
> +    /* PC and SP (for m68k) will be initialized by the reset handler */
> +    s->exception_index = EXCP_RESET;
>  }
> 
> @@ -378,6 +380,8 @@ static void m68k_interrupt_all(CPUM68KState *env, int 
> is_hw)
>          cpu_m68k_set_sr(env, sr &= ~SR_M);
>          sp = env->aregs[7] & ~1;
>          do_stack_frame(env, &sp, 1, oldsr, 0, retaddr);
> +    } else if (cs->exception_index == EXCP_RESET) {
> +        sp = cpu_ldl_kernel(env, env->vbr + vector - 4);
>      } else {
>          do_stack_frame(env, &sp, 0, oldsr, 0, retaddr);
>      }

It looks better of what I have already coded :)

Do you work using code in
https://github.com/vivier/qemu-m68k , branch q800-dev ?

I'm already emulating a Quadra 800, it can help for Macintosh-128k

Thanks,
Laurent