X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/3903760236c30e3b5ace7a4eefac3a269d68957c..cc8bc92ae4a8e9f1a1ab61bf83d34ad8150b3405:/osfmk/kern/bits.h

diff --git a/osfmk/kern/bits.h b/osfmk/kern/bits.h
index 0305208a8..5c977497d 100644
--- a/osfmk/kern/bits.h
+++ b/osfmk/kern/bits.h
@@ -47,11 +47,35 @@ typedef unsigned int			uint;
 #define bit_clear(x, b)			((x) &= ~BIT(b))
 #define bit_test(x, b)			((bool)((x) & BIT(b)))
 
+/* Non-atomically clear the bit and returns whether the bit value was changed */
+inline static bool
+bit_clear_if_set(uint64_t bitmap, int bit)
+{
+    bool bit_is_set = bit_test(bitmap, bit);
+    bit_clear(bitmap, bit);
+    return bit_is_set;
+}
+
+/* Non-atomically set the bit and returns whether the bit value was changed */
+inline static bool
+bit_set_if_clear(uint64_t bitmap, int bit)
+{
+    bool bit_is_set = bit_test(bitmap, bit);
+    bit_set(bitmap, bit);
+    return !bit_is_set;
+}
+
 /* Returns the most significant '1' bit, or -1 if all zeros */
 inline static int
 bit_first(uint64_t bitmap)
 {
+#if defined(__arm64__)
+	int64_t result;
+	asm volatile("clz %0, %1" : "=r" (result) : "r" (bitmap));
+	return 63 - (int)result;
+#else
 	return (bitmap == 0) ? -1 : 63 - __builtin_clzll(bitmap);
+#endif
 }