From:	firewind <firewind AT metroid DOT dyn DOT ml DOT org>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: GCC: Is it possible to set int=16bit
Date:	6 Nov 1997 02:18:10 GMT
Organization:	Netcom
Lines:	40
Message-ID:	<63r9d2$t54@dfw-ixnews8.ix.netcom.com>
References:	<3460bcb1 DOT 8980759 AT news DOT image DOT dk>
NNTP-Posting-Host:	elp-tx3-15.ix.netcom.com
Mime-Version:	1.0
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Sam Ravnborg <sam DOT ravnborg AT image DOT dk> wrote:
> I have downloded DJGPP and like the look and feel of RHIDE (yes, I
> used Borland in the past).
> I am looking for an easy way to test my programs which int the end
> will run on an embedded target.
> I would like to use RHIDE/GCC to compile my programs if possible.

> In first place GCC fails because sizeof(int) == 4bytes == 32 bits.

> The requirements I have is:
> sizeof(int) == 2 bytes
> little endian
> alignment within records: ints are aligned to an even address.
> enums with less than 128 members s one byte in size.
> one byte equals 8 bits.

> My question is:
> Are there any easy way to setup GCC to these requirements - I know I
> have to figure out how to compile GCC etc. but want to hear any
> suggestion to the above first.

a 'short' under DJGPP is two bytes long.

Specific length requirements for variables should definetly be hidden behind
typedefs in C89. This makes porting much easier, since changing a single line:

typedef int two_bytes;

to

typedef short two_bytes;

is much easier then changing ten thousand instances of 'int' to 'short.'

-- 
[-                               firewind                                   -]
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[-          "You're just jealous because the voices talk to -me-."          -]
[-                   Have a good day, and enjoy your C.		            -]
[-          (on a crusade of grumpiness where grumpiness is due)            -]

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