swap out Linux fls for FreeBSD fls implementation

libkd/an-fls.h

@@ -1,14 +1,35 @@
-/**
- This file includes code copied from three source files in the Linux kernel
- v 2.6.23.1:
- - include/asm-generic/bitops/fls.h
- - include/asm-i386/bitops.h
- - include/asm-x86_64/bitops.h
-
- The second and third files contain this notice:
- * Copyright 1992, Linus Torvalds.
-
- And of course the kernel is distributed under the terms of the GPL v2.
+/*-
+ * This file is derived from FreeBSD's sys/libkern/fls.c, with modifications
+ * by the Astrometry.net team.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1990, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
  */
 
 #ifndef AN_FLS_H
@@ -17,125 +38,29 @@
 #include <stdint.h>
 #include <assert.h>
 
-/**
- * fls - find last (most-significant) bit set
- *
- * @x: the word to search
- *
- * This is defined the same way as ffs.
- *
- * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
+/*
+ * Find Last Set bit
  */
-static inline int an_fls(int x);
+static inline int
+BSD_fls(int mask)
+{
+	int bit;
+
+	if (mask == 0)
+		return (0);
+	for (bit = 1; mask != 1; bit++)
+		mask = (unsigned int)mask >> 1;
+	return (bit);
+}
 
-/**
+
+/*
  * flsB()  =  fls() - 1.
  *
  * Note that x MUST be > 0.
  */
-static inline uint8_t an_flsB(uint32_t x);
-
-
-
-/**** Below this line are the implementations for different CPUs. ****/
-
-#if AN_I386
-
-static inline int an_fls(int x) {
-    int r;
-    __asm__("bsrl %1,%0\n\t"
-            "jnz 1f\n\t"
-            "movl $-1,%0\n"
-            "1:" : "=r" (r) : "rm" (x));
-    return r+1;
-} 
-
-static inline uint8_t an_flsB(uint32_t x) {
-    int r;
-    assert(x);
-    __asm__("bsrl %1,%0\n\t"
-            "jnz 1f\n\t"
-            "movl $-1,%0\n"
-            "1:" : "=r" (r) : "rm" (x));
-    return r;
-} 
-
-#elif AN_X86_64
-
-static __inline__ int an_fls(int x) {
-    int r;
-    __asm__("bsrl %1,%0\n\t"
-            "cmovzl %2,%0"
-            : "=&r" (r) : "rm" (x), "rm" (-1));
-    return r+1;
-} 
-
 static inline uint8_t an_flsB(uint32_t x) {
-    int r;
-    assert(x);
-    __asm__("bsrl %1,%0\n\t"
-            "cmovzl %2,%0"
-            : "=&r" (r) : "rm" (x), "rm" (-1));
-    return r;
-}
-
-#else
-
-static inline int an_fls(int x) {
-    int r = 32;
-    if (!x)
-        return 0;
-    if (!(x & 0xffff0000u)) {
-        x <<= 16;
-        r -= 16;
-    }
-    if (!(x & 0xff000000u)) {
-        x <<= 8;
-        r -= 8;
-    }
-    if (!(x & 0xf0000000u)) {
-        x <<= 4;
-        r -= 4;
-    }
-    if (!(x & 0xc0000000u)) {
-        x <<= 2;
-        r -= 2;
-    }
-    if (!(x & 0x80000000u)) {
-        x <<= 1;
-        r -= 1;
-    }
-    return r;
-}
-
-static inline uint8_t an_flsB(uint32_t x) {
-    int r = 31;
-    assert(x);
-    if (!(x & 0xffff0000u)) {
-        x <<= 16;
-        r -= 16;
-    }
-    if (!(x & 0xff000000u)) {
-        x <<= 8;
-        r -= 8;
-    }
-    if (!(x & 0xf0000000u)) {
-        x <<= 4;
-        r -= 4;
-    }
-    if (!(x & 0xc0000000u)) {
-        x <<= 2;
-        r -= 2;
-    }
-    if (!(x & 0x80000000u)) {
-        x <<= 1;
-        r -= 1;
-    }
-    return r;
+    return BSD_fls(x)-1;
 }
 
 #endif
-
-#endif
-
-

libkd/test_libkd.c

@@ -242,10 +242,7 @@ void test_2(CuTest* ct) {
 
     for (i=0; i<N; i++) {
         int L1 = node_level(i);
-        int L2 = an_fls(i+1) - 1;
         int L3 = an_flsB(i+1);
-        //printf("%i %i %i\n", L1, L2, L3);
-        CuAssertIntEquals(ct, L1, L2);
         CuAssertIntEquals(ct, L1, L3);
     }
 }