Yes but as you've said, it's a carry flag setter, but how could this example be transformed if I need to store not only carry flag but also for example a zero flag? Could you write such an example, please?
Thanks.
Dmitry.
--- Исходное сообщение ---
От кого: "Ian Lance Taylor" <iant@xxxxxxxxxx>
Кому: "Dmitry" <mittie@xxxxxxx>
Дата: 5 мая 2011, 17:41:38
Тема: Re: Back end question.
> "Dmitry" <mittie@xxxxxxx> writes:
>
> > Ok but if people do not set each status bit individually, how do they set several not related bits in one CC mode and in one set rtx?
>
> They represent the collection of bits as a mode, as you've been
> discussing.
>
> E.g., from config/i386/i386.md
>
> (define_insn "*<plusminus_insn><mode>3_cc_overflow"
> [(set (reg:CCC FLAGS_REG)
> (compare:CCC
> (plusminus:SWI
> (match_operand:SWI 1 "nonimmediate_operand" "<comm>0,0")
> (match_operand:SWI 2 "<general_operand>" "<r><i>,<r>m"))
> (match_dup 1)))
> (set (match_operand:SWI 0 "nonimmediate_operand" "=<r>m,<r>")
> (plusminus:SWI (match_dup 1) (match_dup 2)))]
> "ix86_binary_operator_ok (<CODE>, <MODE>mode, operands)"
> "<plusminus_mnemonic>{<imodesuffix>}\t{%2, %0|%0, %2}"
> [(set_attr "type" "alu")
> (set_attr "mode" "<MODE>")])
>
>
> Here the CCC mode (defined in i386-modes.def) means that the carry flag
> is valid.
>
> Ian
>
>
