Date: Mon, 4 Jan 1999 09:43:36 +0200 (IST) From: Eli Zaretskii X-Sender: eliz AT is To: Bob Babcock cc: djgpp AT delorie DOT com Subject: Re: Check cache beyond 64MB with djgpp? In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Reply-To: djgpp AT delorie DOT com On 3 Jan 1999, Bob Babcock wrote: > Has anyone written a cache-checking program using the djgpp functions such as > __djgpp_map_physical_memory()? I've seen several programs which will tell > you the size of your L1 and L2 caches, but none seem to want to test beyond > 64MB. I believe this is a wrong approach. __djgpp_map_physical_memory goes through the DPMI server, and many DPMI servers won't let you access more than 64MB of memory. (See section 3.10 of the DJGPP FAQ list for more on this.) What you need is to access raw extended memory using a physical (as opposed to logical) address. It strikes me that the easiest way to accomplish this would be to write a real-mode program that issues XMS calls to allocate buffers in the extended memory, and moves data between them. Another possibility would be to write a DJGPP program that issues XMS calls like above, and run it in plain DOS mode (no Windows) with EMM386 installed as a memory manager. The above is not tested at all, so caveat emptor.