#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_ */