[TUHS] Unix stories

Steffen Nurpmeso steffen at sdaoden.eu
Thu Jan 5 03:08:48 AEST 2017


Random832 <random832 at fastmail.com> wrote:
 |On Wed, Jan 4, 2017, at 11:51, Steffen Nurpmeso wrote:
 |> Ok, but that quite clearly was not what i have meant.  I meant
 |> that if you program in assembler, well, all those newer assembler
 |> languages that i have seen, the target of an operation is the
 |> target of a store, and say if it is a register that is also one of
 |> the sources, it means nothing, from the language side.
 |
 |Yes but you are storing *twice*, two different values, to the same
 |variable, in the same statement. There's no operation in any assembler
 |language that does that, and at this point I honestly don't know what
 |value you expect to 'win'.

Hm.  Yet this is exactly what i want?  (Hihi.  Don't be offended,
i really have already forgotten the example.  It was something
like "*i = j + *i++" or the like..)

 |>  ARM has
 |> even predicates that perform operations on that value before the
 |> store, even if the source is the same as the destination.  It
 |> simply strives me absurd that i, in C, cannot simply say what
 |> i want
 |
 |Why do you think that "i = ... + ++i" is a reasonable way to say what
 |you want?

Man, i write it down, and it even stands several code iterations?
That must be it, then!

 |> and let the C compiler with all its knowledge of the target
 |> system decide what to do about it.

Ciao.

--steffen


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