On 05/25/2011 10:35 PM, Larry Finger wrote:
On 05/25/2011 02:40 PM, Arend van Spriel wrote:
The brcm80211 driver in the staging tree has a cordic function to
determine cosine and sine for a given angle. Feedback received from
John Linville suggested that these kind of functions should be made
available to others as a library function in the kernel tree.
There is a similar routine in b43, thus this library function will likely have
at least 2 users.
I know (forgot to mention it in the commit message). Henry Ptasinski
(broadcom colleague) actually verified both functions against Matlab
implementation (or Scilab, if you prefer open-source ;-) ). The b43
version has a more limited range of the angle input in which the
calculation is accurate.
+static const s32 AtanTbl[] = {
In Documentation/CodingStyle, variables with mixed-case names are frownid upon.
No frowning needed. I will change it ;-)
+/*
+ * cordic_calc_iq() - calculates the i/q coordinate for given angle
+ *
+ * theta: angle in degrees for which i/q coordinate is to be calculated
+ * coord: function output parameter holding the i/q coordinate
+ */
+void cordic_calc_iq(s32 theta, struct cordic_iq *coord)
As "coord" is only for output, why not have this be a function returning a
struct cordic_iq?
Only to avoid passing the structure over the stack. Given the fact that
it is only 8 bytes (4 bytes extra) I think it is ok to change it.
Gr. AvS
--
Almost nobody dances sober, unless they happen to be insane.
-- H.P. Lovecraft --
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