[v20210701,02/40] tools: add API to work with sevaral bits at once

Commit Message

Olaf Hering July 1, 2021, 9:55 a.m. UTC

Introduce new API to test if a fixed number of bits is clear or set,
and clear or set them all at once.

The caller has to make sure the input bitnumber is a multiple of BITS_PER_LONG.

This API avoids the loop over each bit in a known range just to see
if all of them are either clear or set.

Signed-off-by: Olaf Hering <[e-mail]>

v02:
- change return type from int to bool (jgross)
---
 tools/libs/ctrl/xc_bitops.h | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

Patch

diff --git a/tools/libs/ctrl/xc_bitops.h b/tools/libs/ctrl/xc_bitops.h
index f0bac4a071..8e8c6efb45 100644
--- a/tools/libs/ctrl/xc_bitops.h
+++ b/tools/libs/ctrl/xc_bitops.h
@@ -3,6 +3,7 @@ 
 
 /* bitmap operations for single threaded access */
 
+#include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -77,4 +78,31 @@  static inline void bitmap_or(void *_dst, const void *_other,
         dst[i] |= other[i];
 }
 
+static inline bool test_bit_long_set(unsigned long nr_base, const void *_addr)
+{
+    const unsigned long *addr = _addr;
+    unsigned long val = addr[nr_base / BITS_PER_LONG];
+
+    return val == ~0;
+}
+
+static inline bool test_bit_long_clear(unsigned long nr_base, const void *_addr)
+{
+    const unsigned long *addr = _addr;
+    unsigned long val = addr[nr_base / BITS_PER_LONG];
+
+    return val == 0;
+}
+
+static inline void clear_bit_long(unsigned long nr_base, void *_addr)
+{
+    unsigned long *addr = _addr;
+    addr[nr_base / BITS_PER_LONG] = 0;
+}
+
+static inline void set_bit_long(unsigned long nr_base, void *_addr)
+{
+    unsigned long *addr = _addr;
+    addr[nr_base / BITS_PER_LONG] = ~0;
+}
 #endif  /* XC_BITOPS_H */