site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com Would someone mind pointing me to the specific source file in question? Thanks, - Kevin On Jun 1, 2005, at 6:23 AM, Tony Scaminaci wrote: From: Tony Scaminaci <friskythecat@sbcglobal.net> Date: June 1, 2005 8:18:31 AM CDT To: William Kucharski <kucharsk@mac.com> Cc: Tony Scaminaci <friskythecat@sbcglobal.net> Subject: Re: 64-bit problem with VM statistics Available memory: 268267683840MB (281299054850211840 bytes) Tony On Jun 1, 2005, at 1:32 AM, William Kucharski wrote: On May 31, 2005, at 1:28 PM, Tony Scaminaci wrote: What's the "horrendously huge" number? should work just fine on all architectures. William Kucharski kucharsk@mac.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.a... Perhaps the problem is with the format string used to print the number instead of with the number itself? Unfortunately, this is the exact line that's NOT working on 64-bit platforms. FreeMem is returning with the following: The number of bytes (which is what FreeMem is holding) is way too large. It should be around 4613734400 bytes on this particular machine which has about 4400 MB free as shown by top. I received a bug post from John Caldwell who flagged this line of code as having a sign extension issue. He indicated that the correct way to implement this is to cast vm_stat.free_count to an unsigned 32-bit first, then cast the result to an unsigned long long. I'm still not sure of the correct coding and order of typecasting though since he didn't give an example. The following calculation of free memory (in bytes) works correctly on 32-bit platforms. On 64-bit systems (Tiger + G5), the result is a horrendously huge number rather than what is expected. I'm sure this is one of the conversion issues covered in the 64-bit transition guide (which I've read over multiple times already) but I can't seem to nail down the right way to do this calculation for both 32 and 64-bit systems. vm_size_t mac_pagesize; unsigned long long FreeMem; // Free real (physical) memory in bytes The correct way to do this is to cast the number of pages to an unsigned long long and multiply it by mac_pagesize, so the initial code sample you had: FreeMem = ((unsigned long long) vm_stat.free_count) * mac_pagesize; This email sent to site_archiver@lists.apple.com