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* [Qemu-devel] Decode of MIPS DMFC0 and DMTC0
@ 2007-01-10 20:32 Dirk Behme
  2007-01-10 23:44 ` Thiemo Seufer
  0 siblings, 1 reply; 2+ messages in thread
From: Dirk Behme @ 2007-01-10 20:32 UTC (permalink / raw)
  To: qemu-devel

Hi,

looking into target-mips/translate.c, in function 
decode_opc() OPC_DMFC0 and OPC_DMTC0 are mapped to gen_cp0() 
if MIPS64 is enabled:

case OPC_CP0:
         op1 = MASK_CP0(ctx->opcode);
         switch (op1) {
         case OPC_MFC0:
         case OPC_MTC0:
#ifdef MIPS_HAS_MIPS64
         case OPC_DMFC0:
         case OPC_DMTC0:
#endif
             gen_cp0(ctx, op1, rt, rd);
             break;

But looking into gen_cp0() in same file, there is no case 
statement for OPC_DMFC0 and OPC_DMTC0. Looks to me that this 
results in a RI exception.

Do I overlook anything here or is DMFC0/DMTC0 decoding 
missing in gen_cp0()?

Dirk

^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: [Qemu-devel] Decode of MIPS DMFC0 and DMTC0
  2007-01-10 20:32 [Qemu-devel] Decode of MIPS DMFC0 and DMTC0 Dirk Behme
@ 2007-01-10 23:44 ` Thiemo Seufer
  0 siblings, 0 replies; 2+ messages in thread
From: Thiemo Seufer @ 2007-01-10 23:44 UTC (permalink / raw)
  To: Dirk Behme; +Cc: qemu-devel

Dirk Behme wrote:
> Hi,
> 
> looking into target-mips/translate.c, in function 
> decode_opc() OPC_DMFC0 and OPC_DMTC0 are mapped to gen_cp0() 
> if MIPS64 is enabled:
> 
> case OPC_CP0:
>         op1 = MASK_CP0(ctx->opcode);
>         switch (op1) {
>         case OPC_MFC0:
>         case OPC_MTC0:
> #ifdef MIPS_HAS_MIPS64
>         case OPC_DMFC0:
>         case OPC_DMTC0:
> #endif
>             gen_cp0(ctx, op1, rt, rd);
>             break;
> 
> But looking into gen_cp0() in same file, there is no case 
> statement for OPC_DMFC0 and OPC_DMTC0. Looks to me that this 
> results in a RI exception.
> 
> Do I overlook anything here or is DMFC0/DMTC0 decoding 
> missing in gen_cp0()?

You are right. Note that the MIPS64 support is highly experimental at
this point, there is e.g. no proper 64bit FPU support, and no 64bit
addressing.


Thiemo

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2007-01-10 20:32 [Qemu-devel] Decode of MIPS DMFC0 and DMTC0 Dirk Behme
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