* tune/freq.c: Add some comments about systems not covered.

1 files changed, 33 insertions, 1 deletions

diff --git a/tune/freq.c b/tune/freq.c
index c14433b25..999cf2501 100644
--- a/tune/freq.c
+++ b/tune/freq.c
@@ -1,6 +1,6 @@
 /* CPU frequency determination.
 
-Copyright 1999, 2000, 2001, 2002, 2003 Free Software Foundation, Inc.
+Copyright 1999, 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
 
 This file is part of the GNU MP Library.
 
@@ -19,6 +19,38 @@ along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
 the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 MA 02111-1307, USA. */
 
+
+/* Currently we don't get a CPU frequency on the following systems,
+
+   alphaev5-cray-unicosmk2.0.6.X
+       times() has been seen at 13.33 ns (75 MHz), which is probably not the
+       cpu frequency.  Measuring the cycle counter against that would be
+       possible though.  But currently we don't use the cycle counter due to
+       unicos having int==8bytes where tune/alpha.asm assumes int==4bytes.
+
+   m68040-unknown-netbsd1.4.1
+       Not sure if the system even knows the cpu frequency.  There's no
+       cycle counter to measure, though we could perhaps make a loop taking
+       a known number of cycles and measure that.
+
+   power-ibm-aix4.2.1.0
+   power2-ibm-aix4.3.1.0
+   powerpc604-ibm-aix4.3.1.0
+   powerpc604-ibm-aix4.3.3.0
+   powerpc630-ibm-aix4.3.3.0
+   powerpc-unknown-netbsd1.6
+       Don't know where any info hides on these.  mftb is not related to the
+       cpu frequency so doesn't help.
+
+   sparc-unknown-linux-gnu [maybe]
+       Don't know where any info hides on this.
+
+   t90-cray-unicos10.0.X
+       The times() call seems to be for instance 2.22 nanoseconds, which
+       might be the cpu frequency (450 mhz), but need to confirm that.
+
+*/
+
 #include "config.h"
 
 #if HAVE_INVENT_H