On Mon, Mar 20, 2017 at 5:15 PM, Luc Van Oostenryck
<luc.vanoostenryck@xxxxxxxxx> wrote:
> Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
> +static int compare_swap(int opcode)
This function can be call "swap_compare", the action part is
swap.
> +{
> + switch (opcode) {
> + case OP_SET_EQ: return OP_SET_EQ;
> + case OP_SET_NE: return OP_SET_NE;
> +
> + case OP_SET_LT: return OP_SET_GT;
> + case OP_SET_LE: return OP_SET_GE;
> + case OP_SET_GT: return OP_SET_LT;
> + case OP_SET_GE: return OP_SET_LE;
> +
> + case OP_SET_A: return OP_SET_B;
> + case OP_SET_AE: return OP_SET_BE;
> + case OP_SET_B: return OP_SET_A;
> + case OP_SET_BE: return OP_SET_AE;
Some very minor micro optimization note.
I take a look at the machine code it generated. It actually generate
a jump table and each jump table has some label entry corresponding
to code fragment like:
movl $28, %eax #, _163
.LVL985:
jmp .L701 #
I think it should be better to use a static array to directly
fetch the new opcode. There is OP_BINCMP and OP_BINCMP_END
to mark the begin and end of the binary compare opcode. That
way there one data table not jump table for control flow.
This comment apply to comparere_opcode() which introduce in the
earlier patch as well.
Chris
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