diff --git a/src/include/86box/vid_voodoo_render.h b/src/include/86box/vid_voodoo_render.h
index 4070dfc1a..e88d21dd5 100644
--- a/src/include/86box/vid_voodoo_render.h
+++ b/src/include/86box/vid_voodoo_render.h
@@ -254,7 +254,7 @@ void voodoo_codegen_close(voodoo_t *voodoo);
                 src_b = (src_b * (255 - dest_a)) / 255;      \
                 break;                                       \
             case AFUNC_ASATURATE:                            \
-                _a        = MIN(src_a, 1 - dest_a);          \
+                _a        = MIN(src_a, 255 - dest_a);        \
                 src_r     = (dest_r * _a) / 255;             \
                 src_g     = (dest_g * _a) / 255;             \
                 src_b     = (dest_b * _a) / 255;             \