+/** checks for l <= x <= h */
+#define _IN_RANGE(x, l, h) ((unsigned)((x) - (l)) <= (unsigned)((h) - (l)))
+
+/** returns true if it's Intel architecture */
+#define ARCH_INTEL(x) _IN_RANGE((x), arch_i386, arch_core)
+
+/** returns true if it's AMD architecture */
+#define ARCH_AMD(x) _IN_RANGE((x), arch_k6, arch_opteron)
+
+#define IS_P6_ARCH(x) (_IN_RANGE((x), arch_pentium_pro, arch_core) || \
+ _IN_RANGE((x), arch_athlon, arch_opteron))
+