Re: [Qemu-devel] [PATCH] SH7750/51: add register BCR3, NCR4, PCR, RTCOR, RTCNT, RTCSR, SDMR2, SDMR3 and fix BCR2 support

[Jean-Christophe PLAGNIOL-VILLARD]

On 00:36 Mon 15 Dec     , Shin-ichiro KAWASAKI wrote:
> Jean-Christophe PLAGNIOL-VILLARD wrote:
>>>>  -
>>>> +static int inline is_sh7751r_cpu(SH7750State * s)
>>>> +{
>>>> +  return (s->cpu->id & (SH_CPU_SH7751R));
>>>> +}
>>>>  /**********************************************************************
>>>>   I/O ports
>>>>  **********************************************************************/
>>>> @@ -212,8 +219,17 @@ static uint32_t sh7750_mem_readw(void *opaque, 
>>>> target_phys_addr_t addr)
>>>>      switch (addr) {
>>>>      case SH7750_BCR2_A7:
>>>>    return s->bcr2;
>>>> +    case SH7750_BCR3_A7:
>>>> +  if(is_sh7751r_cpu(s)) {
>>>> +      return s->bcr3;
>>>> +  } else {
>>>> +      error_access("word read", addr);
>>>> +      assert(0);
>>>> +  }
>>> BCR3 exists not only for SH7751R, but also SH7750.
>>> I think is_shh751r_cpu() check and error handling
>>> should be removed to simplify the differcence.
>> as write in the SH7751r datasheet
>>
>> Bus Control Register 3 (BCR3) (SH7751R Only)
>> Bus Control Register 4 (BCR4) (SH7751R Only)
>>
>> That's why I've add the check
>
> I see.  Your code is right, but let me add one more comment.
>
> - SH7750 and SH7751 ... does not have BCR3 nor BCR4
> - SH7750R and SH7751R ... have BCR3 and BCR4
>
> So, to make it better, how about renaming "is_h7751r_cpu()"
> into "has_bcr3_and_bcr4()"?  It will be like this.
>
> static int inline has_bcr3_and_bcr4(SH7750State * s)
> {
>        return (s->cpu->id & (SH_CPU_SH7750R | SH_CPU_SH7751R));
> }
I've download the SH7750 & SH7751 datasheet and yes as it's only availlable on
'R' cpu revision

I'll update as it
>
>
>>> Compared to 'if' statement, 'switch-case' might be more easy to
>>> understand, like as follows.
>>>   case SH7750_SDMR2 ... SH7750_SDMR2 + SDMR2_REGNB
>> ok elvenif it's a gcc ony extension
>
> Ah, gccism policy seems not clear in QEMU project.
> This extension is used in many hw/*.c, so I guessed it
> as a QEMU's usual implementation style.
> I hope comments on it from main developers.
>
Yes it will be nice

Best Regards,
J.