Re: [Qemu-devel] [RFC] sparc32 MXCC support

[Robert Reif <reif@earthlink.net>]

Blue Swirl wrote:

>On 10/13/07, Robert Reif <reif@earthlink.net> wrote:
>  
>
>>I'm trying to add SuperSparc II MXCC support and need some feedback.
>>
>>Is there a better way to read and write physical memory in 64bit chunks?
>>I'm not sure what I'm doing is portable between 32/64 and big/little endian.
>>    
>>
>
>Thank you for your effort. Applying the patch allows NetBSD on SS-10
>to boot as far as on SS-5, previously it crashed.
>
>I think the code is portable, but I think changing the register type
>to uint32_t and using a DPRINTF system like used in for example
>hw/iommu.c should make the code slightly clearer.
>
I don't have access to chip specs but from reading linux and *bsd code it
appears that the registers are 64 bits wide but sometimes accessed as 32 
bits to get
only the bottom 32 bits.  Do you mean using two uint32_t for a 64 bit
register?  How about a union of 2 uint32_t and a uint64_t.  Is that 
portable?
Never mind.  I just found out there is an ldq_phys and stq_phys.  I'll 
use those.

I looked at DPRINTF but would need a DPRINTF_MMU and DPRINTF_MXCC ...
Would that be acceptable?

>
>For the memory access, ldl/q_phys/stl/q_phys is used in other block
>copy routines. For longer blocks or if the address can be unaligned,
>cpu_physical_memory_read() could be a better choice.
>  
>
>  
>
>>+int cpu_sparc_register (CPUSPARCState *env, const sparc_def_t *def, int cpu);
>>    
>>
>
>unsigned int cpu?
>  
>
OK

>>+                printf("ERROR: helper_ld_asi(asi = %d, size = %d, sign = %d) T0 = %08x: unsupported size\n", asi, size, sign, T0);
>>    
>>
>
>If it's an error to access the registers with different size, you
>should use do_unassigned_access() to report this.
>
>  
>
These are more for me to make sure I catch all the necessary accesses 
without adding unnecessary code.
linux 2.4 and netbsd only use the ones I have implemented.  openboot 
uses more and
also some undocumented ones which are caught by this but I don't know 
how to handle
them yet.  I will use do_unassigned_access where necessary now.

Thanks for the review.