1 files changed, 42 insertions, 0 deletions
diff --git a/byterun/gc.h b/byterun/gc.h
new file mode 100644
index 0000000000..b772f2f28d
--- /dev/null
+++ b/byterun/gc.h
@@ -0,0 +1,42 @@
+#ifndef _gc_
+#define _gc_
+
+
+#include "mlvalues.h"
+
+/* Defined in [major_gc.c]. */
+extern unsigned free_mem_percent_min, free_mem_percent_max;
+
+#define White (0 << 8)
+#define Gray  (1 << 8)
+#define Blue  (2 << 8)
+#define Black (3 << 8)
+
+#define Color_hd(hd) ((color_t) ((hd) & Black))
+#define Color_hp(hp) Color_hd (Hd_hp (hp))
+
+#define Is_white_hd(hd) (Color_hd (hd) == White)
+#define Is_gray_hd(hd) (Color_hd (hd) == Gray)
+#define Is_blue_hd(hd) (Color_hd (hd) == Blue)
+#define Is_black_hd(hd) (Color_hd (hd) == Black)
+
+#define Whitehd_hd(hd) ((hd) & ~Black)
+#define Grayhd_hd(hd) (((hd) & ~Black) | Gray)
+#define Blackhd_hd(hd) ((hd) | Black)
+#define Bluehd_hd(hd) (((hd) & ~Black) | Blue)
+
+/* This depends on the layout of the header.  See [mlvalues.h]. */
+#define Make_header(wosize, tag, color)					      \
+       ((header_t) (((header_t) (wosize) << 10)				      \
+		    + (color)						      \
+		    + (tag_t) (tag)))
+
+#define Color_val(val) (Color_hd (Hd_val (val)))
+
+#define Is_white_val(val) (Color_val(val) == White)
+#define Is_gray_val(val) (Color_val(val) == Gray)
+#define Is_blue_val(val) (Color_val(val) == Blue)
+#define Is_black_val(val) (Color_val(val) == Black)
+
+
+#endif /* _gc_ */