[Libclc-dev] [PATCH 2/2] math: Add tan implementation

[Aaron Watry]

Uses the algorithm:
tan(x) = sin(x) / sqrt(1-sin^2(x))

An alternative is:
tan(x) = sin(x) / cos(x)

Which produces more verbose bitcode and longer assembly.

Either way, the generated bitcode seems pretty nasty and a more optimized
but still precise-enough solution is welcome.

Signed-off-by: Aaron Watry <awatry at gmail.com>
---
 generic/include/clc/clc.h        | 1 +
 generic/include/clc/math/tan.h   | 2 ++
 generic/include/clc/math/tan.inc | 1 +
 generic/lib/SOURCES              | 1 +
 generic/lib/math/tan.cl          | 8 ++++++++
 generic/lib/math/tan.inc         | 8 ++++++++
 6 files changed, 21 insertions(+)
 create mode 100644 generic/include/clc/math/tan.h
 create mode 100644 generic/include/clc/math/tan.inc
 create mode 100644 generic/lib/math/tan.cl
 create mode 100644 generic/lib/math/tan.inc

diff --git a/generic/include/clc/clc.h b/generic/include/clc/clc.h
index 079c674..69e44b6 100644
--- a/generic/include/clc/clc.h
+++ b/generic/include/clc/clc.h
@@ -60,6 +60,7 @@
 #include <clc/math/sin.h>
 #include <clc/math/sincos.h>
 #include <clc/math/sqrt.h>
+#include <clc/math/tan.h>
 #include <clc/math/trunc.h>
 #include <clc/math/native_cos.h>
 #include <clc/math/native_divide.h>
diff --git a/generic/include/clc/math/tan.h b/generic/include/clc/math/tan.h
new file mode 100644
index 0000000..d2d52a9
--- /dev/null
+++ b/generic/include/clc/math/tan.h
@@ -0,0 +1,2 @@
+#define __CLC_BODY <clc/math/tan.inc>
+#include <clc/math/gentype.inc>
diff --git a/generic/include/clc/math/tan.inc b/generic/include/clc/math/tan.inc
new file mode 100644
index 0000000..50c5b1d
--- /dev/null
+++ b/generic/include/clc/math/tan.inc
@@ -0,0 +1 @@
+_CLC_OVERLOAD _CLC_DECL __CLC_GENTYPE tan(__CLC_GENTYPE x);
diff --git a/generic/lib/SOURCES b/generic/lib/SOURCES
index 30e182f..0667d14 100644
--- a/generic/lib/SOURCES
+++ b/generic/lib/SOURCES
@@ -48,6 +48,7 @@ math/pown.cl
 math/sin.cl
 math/sincos.cl
 math/sincos_helpers.cl
+math/tan.cl
 relational/all.cl
 relational/any.cl
 relational/isequal.cl
diff --git a/generic/lib/math/tan.cl b/generic/lib/math/tan.cl
new file mode 100644
index 0000000..a447999
--- /dev/null
+++ b/generic/lib/math/tan.cl
@@ -0,0 +1,8 @@
+#include <clc/clc.h>
+
+#ifdef cl_khr_fp64
+#pragma OPENCL EXTENSION cl_khr_fp64 : enable
+#endif
+
+#define __CLC_BODY <tan.inc>
+#include <clc/math/gentype.inc>
diff --git a/generic/lib/math/tan.inc b/generic/lib/math/tan.inc
new file mode 100644
index 0000000..8d9d9fe
--- /dev/null
+++ b/generic/lib/math/tan.inc
@@ -0,0 +1,8 @@
+/*
+ * Note: tan(x) = sin(x)/cos(x) also, but the final assembly ends up being
+ *       twice as long for R600 (maybe for others as well).
+ */
+_CLC_OVERLOAD _CLC_DEF __CLC_GENTYPE tan(__CLC_GENTYPE x) {
+  __CLC_GENTYPE sinx = sin(x);
+  return sinx / sqrt( (__CLC_GENTYPE) 1.0 - (sinx*sinx) );
+}
-- 
1.9.1