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Rockbox mail archiveSubject: Re: file read/write codeRe: file read/write code
From: Björn Stenberg <bjorn_at_haxx.se>
Date: Fri, 8 Nov 2002 17:38:00 +0100 Greg Haerr wrote: > Let me know what you think of this. Correct me if I'm wrong, but it looks like you sacrify 50% transfer speed for simpler code. Your code buffers all sectors. That's what makes it simple - read() does not need to bother about which sectors are cached and not. It just memcpies everything. The penalty is harsh, though. Your code copies every byte twice (disk->buffer, buffer->target), while the current code only copies once (disk->target, except for head and tail bytes). Is there a simple way around this that I don't see? > Take a look at the gcc -S output and you'll see huge differences > with code speed and size when an unsigned divide or modulo > is computed, versus a signed divide/modulo. Thanks for the heads-up. Although I prefer to use unsigned int rather than long. -- BjörnReceived on 2002-11-08 Page template was last modified "Tue Sep 7 00:00:02 2021" The Rockbox Crew -- Privacy Policy |