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SubjectRE: [PATCH 02/10][v6] powerpc/Power7: detect load/store instructions
Date
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> Implement instr_is_load_store_2_06() to detect whether a given instruction
> is one of the fixed-point or floating-point load/store instructions in the
> POWER Instruction Set Architecture v2.06.
...
> +int instr_is_load_store_2_06(const unsigned int *instr)
> +{
> + unsigned int op, upper, lower;
> +
> + op = instr_opcode(*instr);
> +
> + if ((op >= 32 && op <= 58) || (op == 61 || op == 62))
> + return true;
> +
> + if (op != 31)
> + return false;
> +
> + upper = op >> 5;
> + lower = op & 0x1f;
> +
> + /* Short circuit as many misses as we can */
> + if (lower < 3 || lower > 23)
> + return false;
> +
> + if (lower == 3) {
> + if (upper >= 16)
> + return true;
> +
> + return false;
> + }
> +
> + if (lower == 7 || lower == 12)
> + return true;
> +
> + if (lower >= 20) /* && lower <= 23 (implicit) */
> + return true;
> +
> + return false;
> +}

I can't help feeling the code could do with some comments about
which actual instructions are selected where.

David





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