added cuda examples

examples_cuda/mandelbrot_tasks3d/mandelbrot_task.ispc

@@ -0,0 +1,91 @@
+#ifdef __NVPTX__  
+#define blockIndex0 blockIndex0()
+#define blockIndex1 blockIndex1()
+#define vectorWidth warpSize()
+#define vectorIndex laneIndex()
+#else
+#define blockIndex0 taskIndex0
+#define blockIndex1 taskIndex1
+#define vectorWidth programCount
+#define vectorIndex programIndex
+#endif
+
+#if 0
+
+varying float mem_private[100];
+uniform float mem_shared [100];
+
+#else
+
+  static inline int
+mandel(float c_re, float c_im, int count) 
+{
+  float z_re = c_re, z_im = c_im;
+  int i;
+  for (i = 0; i < count; ++i) {
+    if (z_re * z_re + z_im * z_im > 4.f)
+      break;
+
+    float new_re = z_re*z_re - z_im*z_im;
+    float new_im = 2.f * z_re * z_im;
+    unmasked {
+      z_re = c_re + new_re;
+      z_im = c_im + new_im;
+    }
+  }
+
+  return i;
+}
+
+
+task void
+mandelbrot_scanline(
+    uniform float x0, uniform float dx, 
+    uniform float y0, uniform float dy,
+    uniform int width, uniform int height, 
+    uniform int xspan, uniform int yspan,
+    uniform int maxIterations, uniform int output[]) 
+{
+  const uniform int xstart = blockIndex0 * xspan;
+  const uniform int xend   = min(xstart  + xspan, width);
+
+  const uniform int ystart = blockIndex1 * yspan;
+  const uniform int yend   = min(ystart  + yspan, height);
+
+//  assert(xspan >= vectorWidth);
+
+  for (uniform int yi = ystart; yi < yend; yi++)
+    for (uniform int xi = xstart; xi < xend; xi += vectorWidth)
+    {
+      const float x = x0 + (xi + vectorIndex) * dx;
+      const float y = y0 +  yi              * dy;
+
+      const int res = mandel(x,y,maxIterations);
+      const int index = yi * width + (xi + vectorIndex);
+      if (xi + vectorIndex < xend)
+        output[index] = res;
+    }
+}
+
+#if 1
+export void
+mandelbrot_ispc(uniform float x0, uniform float y0, 
+                uniform float x1, uniform float y1,
+                uniform int width, uniform int height, 
+                uniform int maxIterations, uniform int output[]) {
+    uniform float dx = (x1 - x0) / width;
+    uniform float dy = (y1 - y0) / height;
+    const uniform int xspan = 32;  /* make sure it is big enough to avoid false-sharing */
+    const uniform int yspan = 4; 
+
+    launch [width/xspan, height/yspan]
+      mandelbrot_scanline(x0, dx, y0, dy, width, height, xspan, yspan,
+                          maxIterations, output);
+#if 0
+    launch [width/xspan] [height/yspan]
+      mandelbrot_scanline(x0, dx, y0, dy, width, height, xspan, yspan,
+                          maxIterations, output);
+#endif
+}
+#endif
+#endif