diff --git a/dlls/d3dx9_36/math.c b/dlls/d3dx9_36/math.c
index e73530376be..2cf22d74222 100644
--- a/dlls/d3dx9_36/math.c
+++ b/dlls/d3dx9_36/math.c
@@ -87,7 +87,7 @@ D3DXMATRIX* WINAPI D3DXMatrixAffineTransformation2D(
 /*************************************************************************
  * D3DXMatrixDecompose
  */
-HRESULT WINAPI D3DXMatrixDecompose(D3DXVECTOR3 *poutscale, D3DXQUATERNION *poutrotation, D3DXVECTOR3 *pouttranslation, D3DXMATRIX *pm)
+HRESULT WINAPI D3DXMatrixDecompose(D3DXVECTOR3 *poutscale, D3DXQUATERNION *poutrotation, D3DXVECTOR3 *pouttranslation, CONST D3DXMATRIX *pm)
 {
     D3DXMATRIX normalized;
     D3DXVECTOR3 vec;
diff --git a/include/d3dx9math.h b/include/d3dx9math.h
index 83b87493a5a..a03379639c1 100644
--- a/include/d3dx9math.h
+++ b/include/d3dx9math.h
@@ -266,9 +266,9 @@ extern "C" {
 D3DXCOLOR* WINAPI D3DXColorAdjustContrast(D3DXCOLOR *pout, CONST D3DXCOLOR *pc, FLOAT s);
 D3DXCOLOR* WINAPI D3DXColorAdjustSaturation(D3DXCOLOR *pout, CONST D3DXCOLOR *pc, FLOAT s);
 
-D3DXMATRIX* WINAPI D3DXMatrixAffineTransformation(D3DXMATRIX *pout, float scaling, D3DXVECTOR3 *rotationcenter, D3DXQUATERNION *rotation, D3DXVECTOR3 *translation);
+D3DXMATRIX* WINAPI D3DXMatrixAffineTransformation(D3DXMATRIX *pout, FLOAT scaling, CONST D3DXVECTOR3 *rotationcenter, CONST D3DXQUATERNION *rotation, CONST D3DXVECTOR3 *translation);
 D3DXMATRIX* WINAPI D3DXMatrixAffineTransformation2D(D3DXMATRIX *pout, FLOAT scaling, CONST D3DXVECTOR2 *protationcenter, FLOAT rotation, CONST D3DXVECTOR2 *ptranslation);
-HRESULT WINAPI D3DXMatrixDecompose(D3DXVECTOR3 *poutscale, D3DXQUATERNION *poutrotation, D3DXVECTOR3 *pouttranslation, D3DXMATRIX *pm);
+HRESULT WINAPI D3DXMatrixDecompose(D3DXVECTOR3 *poutscale, D3DXQUATERNION *poutrotation, D3DXVECTOR3 *pouttranslation, CONST D3DXMATRIX *pm);
 FLOAT WINAPI D3DXMatrixDeterminant(CONST D3DXMATRIX *pm);
 D3DXMATRIX* WINAPI D3DXMatrixInverse(D3DXMATRIX *pout, FLOAT *pdeterminant, CONST D3DXMATRIX *pm);
 D3DXMATRIX* WINAPI D3DXMatrixLookAtLH(D3DXMATRIX *pout, CONST D3DXVECTOR3 *peye, CONST D3DXVECTOR3 *pat, CONST D3DXVECTOR3 *pup);