On 11/24/20 4:59 PM, Richard Henderson wrote:
> On 11/24/20 5:45 AM, Philippe Mathieu-Daudé wrote:
>> Release 6 recoded the 'Load Linked Word' using SPECIAL3 opcode,
>> this opcode (0b110000) is now reserved.
>>
>> Ref: A.2 Instruction Bit Encoding Tables:
>>
>>   "6Rm instructions signal a Reserved Instruction exception
>>    when executed by a Release 6 implementation."
>>
>> The check was added in commit 4368b29a26e ("target-mips: move
>> LL and SC instructions") but got lost during latter refactor
>> in commit d9224450208 ("target-mips: Tighten ISA level checks").
> 
> I think git blame is confused here -- d9224450208 isn't the one that broke
> things.  The patch has:
> 
> 
> +    case OPC_LL: /* Load and stores */
> +        check_insn(ctx, ISA_MIPS2);
> +        /* Fallthrough */
> +    case OPC_LWL:
>      case OPC_LWR:
> -    case OPC_LL:
>          check_insn_opc_removed(ctx, ISA_MIPS32R6);
> +         /* Fallthrough */

Sorry I have been confused by the /* Fallthrough */ ...

The check is below.

Self-NAck then.

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