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Mail Archives: djgpp/2003/01/21/20:31:14

From: "Joel_S" <jbs30000 DOT news DOT invalid AT web2news DOT net>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: C/C++ versions of asm opcodes.
Date: Wed, 22 Jan 2003 01:44:13 +0100
Organization: Web2news.com
Message-ID: <12333N451@web2news.com>
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Reply-To: djgpp AT delorie DOT com

Thank you.
> Joel_S wrote:
>>
>> Ok, there are some C/C++ functions for asm opcodes, like
>> << and
>>>> for shl and shr (using Intel assembly syntax instead of AT&T).
>> And I know how to translate some opcodes that don't have a C/C++
>> equivalent.  But there are some things in asm that I'm wondering
>> if I could do in C or C++, like
>> ror
>> rol
>> adc
>> sbb
>> if anybody knows how to do these in C, I'd like to know.  Thanks.
>
> /* untested example */
> unsigned int ror(unsigned int n)
> {
>    unsigned int signbit, sign;
>
>    signbit = UINT_MAX - INT_MAX;  /* shaky here */
>    sign = (n & 1) * signbit;
>    n = (n >> 1) | sign;
>    return n;
> }

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