From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <4C18D1D8.2060301@maht0x0r.net>
Date: Wed, 16 Jun 2010 14:30:00 +0100
From: maht <maht-9fans@maht0x0r.net>
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To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net>
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Subject: Re: [9fans] portability question
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On 06/16/10 10:11, hugo rivera wrote:
> Can someone clarify why the program included outputs 'AB000000' (as I
> expect) on 32 bit systems and 'FFFFFFFFAB000000' on 64 bit systems?
> where all those 1's came from? what's the portable way of doing this?
> sorry for newbie questions like this.
>
>
>        unsigned long l;
>         unsigned char c;
>
>         l = 0L;
>         c = 0xAB;
>         l |= c << 24;
>         printf("%lX\n", l);
>
>

check the ASM, looks like c is being cast as signed and then sign
extended into a long and then ORed with l.

perhaps this would solve it :

l |= ((unsigned long) c) << 24


But I can't check