diff --git a/dlls/ddraw/tests/ddraw1.c b/dlls/ddraw/tests/ddraw1.c
index d85d31343ff..16c0cfb4e5b 100644
--- a/dlls/ddraw/tests/ddraw1.c
+++ b/dlls/ddraw/tests/ddraw1.c
@@ -8205,7 +8205,7 @@ static void test_color_fill(void)
                 float f, g;
 
                 expected = tests[i].result & mask;
-                f = ceilf(log2f(expected + 1.0f));
+                f = ceilf(logf(expected + 1.0f) / logf(2.0f));
                 g = (f + 1.0f) / 2.0f;
                 g -= (int)g;
                 expected_broken = (expected / exp2f(f) - g) * 256;
diff --git a/dlls/ddraw/tests/ddraw2.c b/dlls/ddraw/tests/ddraw2.c
index 9ca6b44eb87..f0ae458d851 100644
--- a/dlls/ddraw/tests/ddraw2.c
+++ b/dlls/ddraw/tests/ddraw2.c
@@ -8953,7 +8953,7 @@ static void test_color_fill(void)
                 float f, g;
 
                 expected = tests[i].result & mask;
-                f = ceilf(log2f(expected + 1.0f));
+                f = ceilf(logf(expected + 1.0f) / logf(2.0f));
                 g = (f + 1.0f) / 2.0f;
                 g -= (int)g;
                 expected_broken = (expected / exp2f(f) - g) * 256;
diff --git a/dlls/ddraw/tests/ddraw4.c b/dlls/ddraw/tests/ddraw4.c
index 39b4aca6578..7ce33ab4063 100644
--- a/dlls/ddraw/tests/ddraw4.c
+++ b/dlls/ddraw/tests/ddraw4.c
@@ -10601,7 +10601,7 @@ static void test_color_fill(void)
                 float f, g;
 
                 expected = tests[i].result & U3(z_fmt).dwZBitMask;
-                f = ceilf(log2f(expected + 1.0f));
+                f = ceilf(logf(expected + 1.0f) / logf(2.0f));
                 g = (f + 1.0f) / 2.0f;
                 g -= (int)g;
                 expected_broken = (expected / exp2f(f) - g) * 256;
diff --git a/dlls/ddraw/tests/ddraw7.c b/dlls/ddraw/tests/ddraw7.c
index c34d9394861..cde5d2b5ba5 100644
--- a/dlls/ddraw/tests/ddraw7.c
+++ b/dlls/ddraw/tests/ddraw7.c
@@ -10575,7 +10575,7 @@ static void test_color_fill(void)
                 float f, g;
 
                 expected = tests[i].result & U3(z_fmt).dwZBitMask;
-                f = ceilf(log2f(expected + 1.0f));
+                f = ceilf(logf(expected + 1.0f) / logf(2.0f));
                 g = (f + 1.0f) / 2.0f;
                 g -= (int)g;
                 expected_broken = (expected / exp2f(f) - g) * 256;