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-rw-r--r--src/include/lib.h18
1 files changed, 12 insertions, 6 deletions
diff --git a/src/include/lib.h b/src/include/lib.h
index 7ad33dd552..b81b1b18bb 100644
--- a/src/include/lib.h
+++ b/src/include/lib.h
@@ -24,12 +24,6 @@
#include <stdint.h>
#include <types.h>
-#if !defined(__ROMCC__) /* Conflicts with inline function in arch/io.h */
-/* Defined in src/lib/clog2.c */
-unsigned long log2(unsigned long x);
-#endif
-unsigned long log2_ceil(unsigned long x);
-
/* Defined in src/lib/lzma.c */
unsigned long ulzma(unsigned char *src, unsigned char *dst);
@@ -49,4 +43,16 @@ int checkstack(void *top_of_stack, int core);
void hexdump(const void *memory, size_t length);
void hexdump32(char LEVEL, const void *d, size_t len);
+#if !defined(__ROMCC__)
+/* Count Leading Zeroes: clz(0) == 32, clz(0xf) == 28, clz(1 << 31) == 0 */
+static inline int clz(u32 x) { return x ? __builtin_clz(x) : sizeof(x) * 8; }
+/* Integer binary logarithm (rounding down): log2(0) == -1, log2(5) == 2 */
+static inline int log2(u32 x) { return sizeof(x) * 8 - clz(x) - 1; }
+/* Find First Set: __ffs(1) == 0, __ffs(0) == -1, __ffs(1<<31) == 31 */
+static inline int __ffs(u32 x) { return log2(x & (u32)(-(s32)x)); }
+#endif
+
+/* Integer binary logarithm (rounding up): log2_ceil(0) == -1, log2(5) == 3 */
+static inline int log2_ceil(u32 x) { return (x == 0) ? -1 : log2(x * 2 - 1); }
+
#endif /* __LIB_H__ */