linux-kernel - Re: Re : Re : Re : Re : [PATCH] Compressed ia32 ELF file generation for loading by Gujin 1/3

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Message-ID: <m14ppyr8c4.fsf@ebiederm.dsl.xmission.com>
Date:	Tue, 06 Feb 2007 19:48:43 -0700
From:	ebiederm@...ssion.com (Eric W. Biederman)
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	Etienne Lorrain <etienne_lorrain@...oo.fr>, vgoyal@...ibm.com,
	linux-kernel@...r.kernel.org
Subject: Re: Re : Re : Re : Re : [PATCH] Compressed ia32 ELF file generation for loading by Gujin 1/3

"H. Peter Anvin" <hpa@...or.com> writes:

> Etienne Lorrain wrote:
>> H. Peter Anvin wrote:
>>> I've long wished that someone would do a proper 16-bit x86 port of gcc;
>>
>>> however, the .code16gcc is usually good enough, although it produces code
>>> which is a lot bigger than it needs to be.
>>
>>   It is only that much bigger if you compare to 16 bits integer compilers,
>>  but once you deal with 32 bits integers in real mode you have one extra byte
>>  out of the two - which is still better than dealing with dx:ax.
>>
>>  Last time I compiled (long time ago) some piece of code with and without
>>  .code16gcc it was approx 15% bigger - approx what you get when optimising.
>>
>
> That's not a valid comparison, because you're using 32-bit registers to hold
> 16-bit pointers, and then sticking 67 prefixes on completely unnecessarily.

Regardless if the size is good enough we can use it :)

For romcc I had a 3x code bloat over had crafted assembler, because I
had no memory and had to inline every single function call because I
didn't have someplace to put a return register.  So I have the
scenario with the most code bloat.  I win!

Eric
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