Add fixed precision sin() and cos()

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@1342 42af7a65-404d-4744-a932-0658087f49c3

7 files changed, 244 insertions, 3 deletions

diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog
index bb73136c1..95d4b9f63 100644
--- a/nuttx/ChangeLog
+++ b/nuttx/ChangeLog
@@ -590,4 +590,5 @@
 
 0.3.20 2008-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr>
 	* Initial release of a tiny windowing system for NuttX (not well tested at initial check-in)
+	* Add fixed precision sin() and cos() (not well tested at initial check-in)
 
diff --git a/nuttx/Documentation/NuttX.html b/nuttx/Documentation/NuttX.html
index 0fdedd3db..6dcce8b58 100644
--- a/nuttx/Documentation/NuttX.html
+++ b/nuttx/Documentation/NuttX.html
@@ -1206,6 +1206,7 @@ buildroot-0.1.2 2007-11-06 &lt;spudmonkey@racsa.co.cr&gt
 <pre><ul>
 nuttx-0.3.20 2008-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;
 	* Initial release of a tiny windowing system for NuttX (not well tested at initial check-in)
+	* Add fixed precision sin() and cos() (not well tested at initial check-in)
 
 pascal-0.1.3 2008-xx-xx Gregory Nutt &lt;spudmonkey@racsa.co.cr&gt;
 
diff --git a/nuttx/include/fixedmath.h b/nuttx/include/fixedmath.h
index 3f9e8e0e6..1c4253754 100644
--- a/nuttx/include/fixedmath.h
+++ b/nuttx/include/fixedmath.h
@@ -54,6 +54,9 @@
 #define b8HALF          0x0080                  /* 0.5 */
 #define b8ONETENTH      0x001a                  /* 0.1 (acutally 0.1015625) */
 #define b8ONEHUNDRTH    0x0003                  /* 0.01 (actualy 0.0117198765) */
+#define b8HALFPI        0x0192                  /* 1.5703125 */
+#define b8PI            0x0324                  /* 3.1406250 */
+#define b8TWOPI         0x0648                  /* 6.2812500 */
 
 #define b8MAX           0x7fff                  /* Max value of b8_t */
 #define ub8MAX          0xffff                  /* Max value of rb8_t */
@@ -68,6 +71,9 @@
 #define b16ONETENTH     0x0000199a              /* 0.1 (actually 0.100006..) */
 #define b16ONEHUNDRTH   0x0000028f              /* 0.01 (actually 0.0099945..) */
 #define b16ONETHOUSTH   0x00000042              /* 0.001 (actually 0.000100708..)*/
+#define b16HALFPI       0x0001921f              /* 1.57078552246 */
+#define b16PI           0x0003243f              /* 3.14158630371 */
+#define b16TWOPI        0x0006487b              /* 6.28312683105 */
 
 #define b16MAX          0x7fffffff              /* Max value of b16_t */
 #define ub16MAX         0xffffffff              /* Max value of ub16_t */
@@ -84,6 +90,9 @@
 #define b32ONEHUNDRTH   0x00000000028f5c29      /* 0.01 */
 #define b32ONETHOUSTH   0x0000000000418937      /* 0.001 */
 #define b32ONETENTHOU   0x0000000000068db9      /* 0.0001 */
+#define b32HALFPI       0x00000001921eb9ff      /* 1.57078134990 */
+#define b32PI           0x00000003243f6b4f      /* 3.14159269980 */
+#define b32TWOPI        0x00000006487ae7fd      /* 6.28312539984 */
 
 #define b32MAX          0x7fffffffffffffff      /* Max value of b16_t */
 #define ub32MAX         0xffffffffffffffff      /* Max value of ub16_t */
@@ -131,6 +140,8 @@
 #define b8mulb8(a,b)    b16tob8((b16_t)(a)*(b16_t)(b) /* Muliplication */
 #define ub8mulub8(a,b)  ub16toub8((ub16_t)(a)*(ub16_t)(b) /* Muliplication */
 #define b8muli(a,i)     ((a)*(i))               /* Simple multiplication by integer */
+#define b8sqr(a)        b8mulb8(a,a)            /* Square */
+#define ub8sqr(a)       ub8mulub8(a,a)          /* Square */
 #define b8divb8(a,b)    b8tob16(a)/(b16_t)(b)   /* Division */
 #define ub8divub8(a,b)  ub8toub16(a)/(ub16_t)(b) /* Division */
 #define b8divi(a,i)     ((a)/(i))               /* Simple division by integer */
@@ -162,9 +173,11 @@
 #define b16idiv(i,j)    (((i)<<16)/j)           /* Division of integer, b16 result */
 
 #ifdef CONFIG_HAVE_LONG_LONG
-#  define b16mulb16(a,b)   b32tob16((b32_t)(a)*(b32_t)(b) /* Muliplication */
+#  define b16mulb16(a,b)   b32tob16((b32_t)(a)*(b32_t)(b)) /* Muliplication */
 #  define ub16mulub16(a,b) ub32toub16((ub32_t)(a)*(ub32_t)(b)
-#  define b16divb16(a,b)   b16tob32(a)/(b32_t)(b)         /* Division */
+#  define b16sqr(a)        b16mulb16(a,a)                  /* Square */
+#  define ub16sqr(a)       ub16mulub16(a,a)                /* Square */
+#  define b16divb16(a,b)   b16tob32(a)/(b32_t)(b)          /* Division */
 #  define ub16divub16(a,b) ub16toub32(a)/(ub32_t)(b)
 #endif
 
@@ -196,10 +209,15 @@ extern "C" {
 #ifndef CONFIG_HAVE_LONG_LONG
 EXTERN b16_t  b16mulb16(b16_t m1, b16_t m2);
 EXTERN ub16_t ub16mulub16(ub16_t m1, ub16_t m2);
+EXTERN b16_t  b16sqr(b16_t a);
+EXTERN ub16_t ub16sqr(ub16_t a);
 EXTERN b16_t  b16divb16(b16_t num, b16_t denom);
 EXTERN ub16_t ub16divub16(ub16_t num, ub16_t denom);
 #endif
 
+EXTERN b16_t b16sin(b16_t rad);
+EXTERN b16_t b16cos(b16_t rad);
+
 #undef EXTERN
 #if defined(__cplusplus)
 }
diff --git a/nuttx/lib/Makefile b/nuttx/lib/Makefile
index c58b2dbcb..47c410309 100644
--- a/nuttx/lib/Makefile
+++ b/nuttx/lib/Makefile
@@ -71,7 +71,7 @@ endif
 
 STDLIB_SRCS	= lib_rand.c
 
-MATH_SRCS	= lib_rint.c lib_fixedmath.c
+MATH_SRCS	= lib_rint.c lib_fixedmath.c lib_b16sin.c lib_b16cos.c
 
 UNISTD_SRCS	= lib_getopt.c
 ifneq ($(CONFIG_NFILE_DESCRIPTORS),0)
diff --git a/nuttx/lib/lib_b16cos.c b/nuttx/lib/lib_b16cos.c
new file mode 100644
index 000000000..93f5ee2f6
--- /dev/null
+++ b/nuttx/lib/lib_b16cos.c
@@ -0,0 +1,64 @@
+/****************************************************************************
+ * lib/lib_b16cos.c
+ *
+ *   Copyright (C) 2007, 2008 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <fixedmath.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: b16cos
+ ****************************************************************************/
+
+b16_t b16cos(b16_t rad)
+{
+  /* Compute cosine: sin(rad + PI/2) = cos(rad) */
+
+  rad += b16HALFPI;
+  if (rad > b16PI)
+    {
+      rad -= b16TWOPI;
+    }
+  return b16sin(rad);
+}
diff --git a/nuttx/lib/lib_b16sin.c b/nuttx/lib/lib_b16sin.c
new file mode 100644
index 000000000..7e2bcac56
--- /dev/null
+++ b/nuttx/lib/lib_b16sin.c
@@ -0,0 +1,110 @@
+/****************************************************************************
+ * lib/lib_b16sin.c
+ *
+ *   Copyright (C) 2008 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <fixedmath.h>
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+#define b16_P225       0x0000399a
+#define b16_P405284735 0x000067c1
+#define b16_1P27323954 0x000145f3
+
+/****************************************************************************
+ * Global Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: b16sin
+ * Ref: http://lab.polygonal.de/2007/07/18/fast-and-accurate-sinecosine-approximation/
+ ****************************************************************************/
+
+b16_t b16sin(b16_t rad)
+{
+  b16_t tmp1;
+  b16_t tmp2;
+  b16_t tmp3;
+
+  /* Force angle into the good range */
+
+  if (rad < -b16PI)
+    {
+      rad += b16TWOPI;
+    }
+  else if (rad > b16PI)
+   {
+      rad -= b16TWOPI;
+   }
+
+  /* tmp1 = 1.27323954 * rad
+   * tmp2 = .405284735 * rad * rad
+   */
+
+
+  tmp1 = b16mulb16(b16_1P27323954, rad);
+  tmp2 = b16mulb16(b16_P405284735, b16sqr(rad));
+
+  if (rad < 0)
+    {
+       /* tmp3 = 1.27323954 * rad + .405284735 * rad * rad */
+
+       tmp3 = tmp1 + tmp2;
+    }
+  else
+    {
+       /* tmp3 = 1.27323954 * rad - 0.405284735 * rad * rad */
+
+       tmp3 = tmp1 - tmp2;
+    }
+
+  /* tmp1 = tmp3*tmp3 */
+
+  tmp1 = b16sqr(tmp3);
+  if (tmp3 < 0)
+    {
+      /* tmp1 = tmp3 * -tmp3 */
+
+      tmp1 = -tmp1;
+    }
+
+  /* Return sin = .225 * (tmp3 * (+/-tmp3) - tmp3) + tmp3 */
+
+  return b16mulb16(b16_P225, (tmp1 - tmp3)) + tmp3;
+}
diff --git a/nuttx/lib/lib_fixedmath.c b/nuttx/lib/lib_fixedmath.c
index 0b09653c5..e5f7ce3a4 100644
--- a/nuttx/lib/lib_fixedmath.c
+++ b/nuttx/lib/lib_fixedmath.c
@@ -165,6 +165,53 @@ ub16_t ub16mulub16(ub16_t m1, ub16_t m2)
  * Name: b16divb16
  **************************************************************************/
 
+b16_t b16sqr(b16_t a)
+{
+  b16_t sq;
+
+  /* The result is always positive.  Just take the absolute value */
+
+  if (a < 0)
+    {
+      a = -a;
+    }
+
+  /* Overflow occurred if the result is negative */
+
+  sq = (bt_t)ub16sqr(a);
+  if (sq < 0)
+    {
+      sq = b16MAX;
+    }
+  return sq;
+}
+
+/****************************************************************************
+ * Name: b16divb16
+ **************************************************************************/
+
+ub16_t ub16sqr(ub16_t a)
+{
+ /* Let:
+ *
+  *   m = mi*2**16 + mf                                               (b16)
+  *
+  * Then:
+  *
+  *  m*m = (mi*mi)*2**32 + 2*(m1*m2)*2**16 + mf*mf                    (b32)
+  *      = (mi*mi)*2**16 + 2*(mi*mf)       + mf*mf*2**-16             (b16)
+  */
+
+  uint32 mi = ((uint32)m1 >> 16);
+  uint32 mf = ((uint32)m1 & 0x0000ffff);
+
+  return (mi*mi << 16) + (mi*mf << 1) (((mf*mf) + b16HALF) >> 16);
+}
+
+/****************************************************************************
+ * Name: b16divb16
+ **************************************************************************/
+
 b16_t b16divb16(b16_t num, b16_t denom)
 {
   boolean negate;