File xen.bitmap-long.patch of Package xen

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File xen.bitmap-long.patch of Package xen

From: Olaf Hering <olaf@aepfle.de>
Date: Wed, 9 Dec 2020 16:40:00 +0100
Subject: bitmap long

tools: add API to work with sevaral bits at once

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 <olaf@aepfle.de>

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

--- a/tools/libs/ctrl/xc_bitops.h
+++ b/tools/libs/ctrl/xc_bitops.h
@@ -1,17 +1,18 @@
 #ifndef XC_BITOPS_H
 #define XC_BITOPS_H 1
 
 /* bitmap operations for single threaded access */
 
+#include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
 
 #ifdef __LP64__
 #define BITS_PER_LONG 64
 #else
 #define BITS_PER_LONG 32
 #endif
 
 #define BITMAP_ENTRY(_nr,_bmap) ((_bmap))[(_nr) / 8]
 #define BITMAP_SHIFT(_nr) ((_nr) % 8)
 
@@ -72,13 +73,40 @@ static inline int test_and_set_bit(unsigned long nr, void *addr)
 }
 
 static inline void bitmap_or(void *_dst, const void *_other,
                              unsigned long nr_bits)
 {
     char *dst = _dst;
     const char *other = _other;
     unsigned long i;
     for ( i = 0; i < bitmap_size(nr_bits); ++i )
         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 */

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