#ifndef __FIRM_HACKDEL_H
#define __FIRM_HACKDEL_H
+#include <limits.h>
+
#include "firm_config.h"
#define HACKDEL_WORDSIZE 32
+/**
+ * Add saturated.
+ * @param x Summand 1.
+ * @param y Summand 2.
+ * @return x + y or INT_MAX/INT_MIN if an overflow occurred and x,y was positive/negative.
+ *
+ * @note See hacker's delight, page 27.
+ */
+static INLINE int add_saturated(int x, int y)
+{
+ int sum = x + y;
+ /*
+ An overflow occurs, if the sign of the both summands is equal
+ and the one of the sum is different from the summand's one.
+ The sign bit is 1, if an overflow occurred, 0 otherwise.
+ int overflow = ~(x ^ y) & (sum ^ x);
+ */
+ int overflow = (x ^ sum) & (y ^ sum);
+
+ /*
+ The infinity to use.
+ Make a mask of the sign bit of x and y (they are the same if an overflow occurred).
+ INT_MIN == ~INT_MAX, so if the sign was negative, INT_MAX becomes INT_MIN.
+ */
+ int inf = (x >> sizeof(x) * 8 - 1) ^ INT_MAX;
+
+ return overflow < 0 ? inf : sum;
+}
+
/**
* Compute the count of set bits in a 32-bit word.
* @param x A 32-bit word.
#define round_up2(x,pot) (((x) + ((pot) - 1)) & (~((pot) - 1)))
+
#endif