[En-Nut-Discussion] Floating Point Memory Usage
bobwirka at yahoo.com
Wed Oct 9 16:27:42 CEST 2013
It's an AT91SAM7X512 with software floating point.
Right on the Ethernet website (which I should have read), regarding floating point, it states that 16K is allocated on the first call to _sbrk(). This is exactly what was happening; _dtoa_r() in putf() was calling _sbrk(), allocating the memory.
I've since written my own d2a() function that doesn't allocate memory. It **seems** to work.
Realtime Control Works
On Wednesday, October 9, 2013 4:44 AM, "bon at elektron.ikp.physik.tu-darmstadt.de" <bon at elektron.ikp.physik.tu-darmstadt.de> wrote:
>>>>> "Bob" == Bob Wirka <bobwirka at yahoo.com> writes:
Bob> Hello, Realized today that floating point eats an automatic 16K of
Bob> ram on the first call to _sbrk(). I should read the manuals...
Bob> It looks like setting LIB_HEAPSIZE to 4K will work (at first,
Bob> anyway), but am I setting myself up for other problems?
Bob> Without the default 16K, is 'newlib' likely to misbehave somewhere
With what processor are you working? What kind of floating point support,
hardware or software? If hardware, what float support did you compile for?
Uwe Bonnes bon at elektron.ikp.physik.tu-darmstadt.de
Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt
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