From: lutz@iks-jena.de (Lutz Donnerhacke)
Subject: Re: Accessing a register with a larger size from generic
Date: Fri, 28 Sep 2001 08:53:51 +0000 (UTC)
Date: 2001-09-28T08:53:51+00:00 [thread overview]
Message-ID: <slrn9r8ekt.kv.lutz@taranis.iks-jena.de> (raw)
In-Reply-To: slrn9r6s3u.pqt.lutz@belenus.iks-jena.de
* Lutz Donnerhacke wrote:
> ------------------------------
>[...with, use, package (body), ...]
>subtype long is Interfaces.C.long;
...
+ for call_code'Size use long'Size;
>
>generic
> call : call_code;
> type type1 is private;
>function syscall1 (arg1 : type1) return long;
>
>function syscall1 (arg1 : type1) return long is
> res : long;
+ function To_Long is Unchecked_Conversion (type1, long);
>begin
> Asm ("int $0x80",
> Outputs => long'Asm_Output ("=a", res),
- Inputs => (call_code'Asm_Input ("0", call),
- type1'Asm_Input ("b", arg1)),
+ Inputs => (long'Asm_Input ("0", To_Long (call)),
+ long'Asm_Input ("b", To_Long (arg1))),
> Volatile => True);
> return res;
>end syscall1;
> ------------------------------
This is a quick and dirty solution, because the user is required to use only
types of the given size. In most cases this requires the following ugly code:
type filedescriptor is new Interfaces.C.int;
type filedescriptor_long is new filedescriptor; -- better subtype?
for filedescriptor_long'Size use Interfaces.C.long'Size; -- ... no: fails
type ... is record ... fd : filedescriptor; ... end record;
for ... use record ... fd at ... range 0 .. 15; ... end record;
function sys_close is new syscall1 (CLOSE, filedescriptor_long);
...
if sys_close (filedescriptor_long (fd)) /= 0 then -- Ugly!
Something I can try?
prev parent reply other threads:[~2001-09-28 8:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-09-27 18:31 Accessing a register with a larger size from generic Lutz Donnerhacke
2001-09-27 19:16 ` David C. Hoos
2001-10-02 8:01 ` Lutz Donnerhacke
2001-09-28 8:53 ` Lutz Donnerhacke [this message]
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