Re: [Qemu-devel] [PATCH 06/24] tcg-mips: Move softmmu slow path out of line

[Paolo Bonzini]

Il 14/05/2014 09:17, Richard Henderson ha scritto:
> +    tcg_out_opc_imm(s, OPC_LW, TCG_REG_A0, TCG_REG_A0, add_off);
> +    tcg_out_opc_reg(s, OPC_AND, TCG_REG_T0, TCG_REG_T0, addrl);
> +
> +    label_ptr[0] = s->code_ptr;
>      tcg_out_opc_br(s, OPC_BNE, TCG_REG_T0, TCG_REG_AT);
> -    tcg_out_nop(s);

I don't remember mips very well, LW cannot be put in the delay slot? 
This would let you fill both delay slots for the 64-bit case.  Or is it 
just that the code becomes harder to follow due to the TARGET_LONG_BITS 
== 64 "if"s?

Alternatively, for 64-bit you could use OR+BNE instead of BNE+NOP+BNE. 
Of course this can be done later, this patchset is already a big 
improvement.

> +    tcg_out_opc_imm(s, OPC_LW, TCG_REG_A0, TCG_REG_A0, add_off);
> +    tcg_out_opc_reg(s, OPC_AND, TCG_REG_T0, TCG_REG_T0, addrl);
> +
> +    label_ptr[0] = s->code_ptr;
>      tcg_out_opc_br(s, OPC_BNE, TCG_REG_T0, TCG_REG_AT);
> -    tcg_out_nop(s);

Same here.

Paolo