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-rw-r--r--src/osd/eigcc.h60
1 files changed, 60 insertions, 0 deletions
diff --git a/src/osd/eigcc.h b/src/osd/eigcc.h
index 69bbeffde07..2c5bf34ba72 100644
--- a/src/osd/eigcc.h
+++ b/src/osd/eigcc.h
@@ -55,6 +55,66 @@ inline bool _addu_64x64_co(uint64_t a, uint64_t b, uint64_t &sum)
***************************************************************************/
/*-------------------------------------------------
+ count_leading_zeros_32 - return the number of
+ leading zero bits in a 32-bit value
+-------------------------------------------------*/
+
+#ifndef count_leading_zeros_32
+#define count_leading_zeros_32 _count_leading_zeros_32
+inline uint8_t _count_leading_zeros_32(uint32_t val)
+{
+ // uses CPU feature if available, otherwise falls back to runtime library call
+ static_assert(sizeof(val) == sizeof(unsigned), "expected 32-bit unsigned int");
+ return uint8_t(unsigned(val ? __builtin_clz(val) : 32));
+}
+#endif
+
+
+/*-------------------------------------------------
+ count_leading_ones_32 - return the number of
+ leading one bits in a 32-bit value
+-------------------------------------------------*/
+
+#ifndef count_leading_ones_32
+#define count_leading_ones_32 _count_leading_ones_32
+inline uint8_t _count_leading_ones_32(uint32_t val)
+{
+ return count_leading_zeros_32(~val);
+}
+#endif
+
+
+/*-------------------------------------------------
+ count_leading_zeros_64 - return the number of
+ leading zero bits in a 64-bit value
+-------------------------------------------------*/
+
+#ifndef count_leading_zeros_64
+#define count_leading_zeros_64 _count_leading_zeros_64
+inline uint8_t _count_leading_zeros_64(uint64_t val)
+{
+ // uses CPU feature if available, otherwise falls back to runtime library call
+ static_assert(sizeof(val) == sizeof(unsigned long long), "expected 64-bit unsigned long long int");
+ return uint8_t(unsigned(val ? __builtin_clzll(val) : 64));
+}
+#endif
+
+
+/*-------------------------------------------------
+ count_leading_ones_64 - return the number of
+ leading one bits in a 64-bit value
+-------------------------------------------------*/
+
+#ifndef count_leading_ones_64
+#define count_leading_ones_64 _count_leading_ones_64
+inline uint8_t _count_leading_ones_64(uint64_t val)
+{
+ return count_leading_zeros_64(~val);
+}
+#endif
+
+
+/*-------------------------------------------------
population_count_32 - return the number of
one bits in a 32-bit value
-------------------------------------------------*/