X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fadt%2Fbitfiddle.h;h=3be8ef060336dc81bc2901ed06b3fc2170117e03;hb=26b9008643da89a023fd6839ded5b9abf21ef328;hp=29ff4387e733c7d74db14aa3ceb38a846fd3febc;hpb=972eca70744a2c9a0e0d472db4f62250cdeee01c;p=libfirm

diff --git a/ir/adt/bitfiddle.h b/ir/adt/bitfiddle.h
index 29ff4387e..3be8ef060 100644
--- a/ir/adt/bitfiddle.h
+++ b/ir/adt/bitfiddle.h
@@ -22,7 +22,6 @@
  * @date    28.9.2004
  * @brief   Functions from hackers delight.
  * @author  Sebastian Hack, Matthias Braun
- * @version $Id$
  */
 #ifndef FIRM_ADT_BITFIDDLE_H
 #define FIRM_ADT_BITFIDDLE_H
@@ -45,8 +44,7 @@ COMPILETIME_ASSERT(UINT_MAX == 4294967295U, uintmax)
  *
  * @note See hacker's delight, page 27.
  */
-static inline
-int add_saturated(int x, int y)
+static inline int add_saturated(int x, int y)
 {
 	int sum      = x + y;
 	/*
@@ -74,14 +72,18 @@ int add_saturated(int x, int y)
  * @param x A 32-bit word.
  * @return The number of bits set in x.
  */
-static inline
-unsigned popcnt(unsigned x) {
+static inline unsigned popcount(unsigned x)
+{
+#if defined(__GNUC__) && __GNUC__ >= 4
+	return __builtin_popcount(x);
+#else
 	x -= ((x >> 1) & 0x55555555);
 	x = (x & 0x33333333) + ((x >> 2) & 0x33333333);
 	x = (x + (x >> 4)) & 0x0f0f0f0f;
 	x += x >> 8;
 	x += x >> 16;
 	return x & 0x3f;
+#endif
 }
 
 /**
@@ -89,17 +91,12 @@ unsigned popcnt(unsigned x) {
  * @param x The word.
  * @return The number of leading (from the most significant bit) zeros.
  */
-static inline
-unsigned nlz(unsigned x) {
-#ifdef USE_X86_ASSEMBLY
-	unsigned res;
+static inline unsigned nlz(unsigned x)
+{
+#if defined(__GNUC__) && __GNUC__ >= 4
 	if(x == 0)
 		return 32;
-
-	__asm__("bsrl %1,%0"
-			: "=r" (res)
-			: "r" (x));
-	return 31 - res;
+	return __builtin_clz(x);
 #else
    unsigned y;
    int n = 32;
@@ -118,17 +115,12 @@ unsigned nlz(unsigned x) {
  * @param x The word.
  * @return The number of trailing zeros.
  */
-static inline
-unsigned ntz(unsigned x) {
-#ifdef USE_X86_ASSEMBLY
-	unsigned res;
+static inline unsigned ntz(unsigned x)
+{
+#if defined(__GNUC__) && __GNUC__ >= 4
 	if(x == 0)
 		return 32;
-
-	__asm__("bsfl %1,%0"
-			: "=r" (res)
-			: "r" (x));
-	return  res;
+	return __builtin_ctz(x);
 #else
 	return HACKDEL_WORDSIZE - nlz(~x & (x - 1));
 #endif
@@ -162,10 +154,9 @@ unsigned ntz(unsigned x) {
  * Returns the biggest power of 2 that is equal or smaller than @p x
  * (see hackers delight power-of-2 boundaries, page 48)
  */
-static inline
-unsigned floor_po2(unsigned x)
+static inline unsigned floor_po2(unsigned x)
 {
-#ifdef USE_X86_ASSEMBLY // in this case nlz is fast
+#if defined(__GNUC__) && __GNUC__ >= 4 // in this case nlz is fast
 	if(x == 0)
 		return 0;
 	// note that x != 0 here, so nlz(x) < 32!
@@ -185,14 +176,13 @@ unsigned floor_po2(unsigned x)
  * @remark x has to be <= 0x8000000 of course
  * @note see hackers delight power-of-2 boundaries, page 48
  */
-static inline
-unsigned ceil_po2(unsigned x)
+static inline unsigned ceil_po2(unsigned x)
 {
 	if(x == 0)
 		return 0;
 	assert(x < (1U << 31));
 
-#ifdef USE_X86_ASSEMBLY // in this case nlz is fast
+#if defined(__GNUC__) && __GNUC__ >= 4 // in this case nlz is fast
 	// note that x != 0 here!
 	return 0x80000000U >> (nlz(x-1) - 1);
 #else
@@ -209,8 +199,7 @@ unsigned ceil_po2(unsigned x)
 /**
  * Tests whether @p x is a power of 2
  */
-static inline
-int is_po2(unsigned x)
+static inline int is_po2(unsigned x)
 {
 	return (x & (x-1)) == 0;
 }