Merge branch 'fp16-tests' into 'master'

ngl: Make the C half-float implementation accessible

See merge request GNOME/gtk!3748

gsk/ngl/fp16.c

@@ -54,7 +54,7 @@ float_to_half (const float x)
   return (b&0x80000000)>>16 | (e>112)*((((e-112)<<10)&0x7C00)|m>>13) | ((e<113)&(e>101))*((((0x007FF000+m)>>(125-e))+1)>>1) | (e>143)*0x7FFF; // sign : normalized : denormalized : saturate
 }
 
-static void
+void
 float_to_half4_c (const float f[4],
                   guint16     h[4])
 {
@@ -64,7 +64,7 @@ float_to_half4_c (const float f[4],
   h[3] = float_to_half (f[3]);
 }
 
-static void
+void
 half_to_float4_c (const guint16 h[4],
                   float         f[4])
 {

gsk/ngl/fp16private.h

@@ -41,6 +41,12 @@ void float_to_half4_f16c (const float f[4],
 void half_to_float4_f16c (const guint16 h[4],
                           float         f[4]);
 
+void float_to_half4_c (const float f[4],
+                       guint16     h[4]);
+
+void half_to_float4_c (const guint16 h[4],
+                       float         f[4]);
+
 G_END_DECLS
 
 #endif

testsuite/gsk/half-float.c

@@ -0,0 +1,72 @@
+#include <gtk/gtk.h>
+
+#include "gsk/ngl/fp16private.h"
+
+static void
+test_constants (void)
+{
+  struct {
+    float f;
+    guint16 h;
+  } tests[] = {
+    { 0.0, FP16_ZERO },
+    { 1.0, FP16_ONE },
+    { -1.0, FP16_MINUS_ONE },
+  };
+
+  for (int i = 0; i < G_N_ELEMENTS (tests); i++)
+    {
+      float f[4];
+      guint16 h[4];
+
+      memset (f, 0, sizeof (f));
+      f[0] = tests[i].f;
+      float_to_half4 (f, h);
+      g_assert_cmpuint (h[0], ==, tests[i].h);
+
+
+      memset (h, 0, sizeof (h));
+      h[0] = tests[i].h;
+      half_to_float4 (h, f);
+      g_assert_cmpfloat (f[0], ==, tests[i].f);
+    }
+}
+
+static void
+test_roundtrip (void)
+{
+  for (int i = 0; i < 100; i++)
+    {
+      float f[4];
+      float f2[4];
+      guint16 h[4];
+
+      do
+        {
+          /* generate a random float thats representable as fp16 */
+          memset (h, 0, sizeof (h));
+          h[0] = g_random_int_range (G_MININT16, G_MAXINT16);
+          half_to_float4 (h, f2);
+        }
+      while (!isnormal (f2[0])); /* skip nans and infs since they don't compare well */
+
+      memset (f, 0, sizeof (f));
+      f[0] = f2[0];
+
+      float_to_half4 (f, h);
+      half_to_float4 (h, f2);
+
+      g_assert_cmpfloat (f[0], ==, f2[0]);
+    }
+}
+
+int
+main (int argc, char *argv[])
+{
+  (g_test_init) (&argc, &argv, NULL);
+
+  g_test_add_func ("/half-float/constants", test_constants);
+  g_test_add_func ("/half-float/roundtrip", test_roundtrip);
+
+  return g_test_run ();
+}

testsuite/gsk/meson.build

@@ -234,7 +234,8 @@ foreach t : tests
 endforeach
 
 internal_tests = [
-  ['diff']
+  [ 'diff' ],
+  [ 'half-float' ],
 ]
 
 foreach t : internal_tests