Commit: d84e2e56c6b96c8de57a71dd3704cc09e365ba51 - qemu (git)

Commit MetaInfo

• Revision: d84e2e56c6b96c8de57a71dd3704cc09e365ba51 (tree)
• Time: 2019-05-08 23:42:00
• Author: Yoshinori Sato <ysato@user...>
• Commiter: Yoshinori Sato

Log Message

qemu/bitops.h: Add extract8 and extract16

Signed-off-by: Yoshinori Sato <[e-mail]>

Change Summary

• modified: include/qemu/bitops.h

Incremental Difference

--- a/include/qemu/bitops.h
+++ b/include/qemu/bitops.h
@@ -301,6 +301,44 @@ static inline uint32_t extract32(uint32_t value, int start, int length)
 }
 
 /**
+ * extract8:
+ * @value: the value to extract the bit field from
+ * @start: the lowest bit in the bit field (numbered from 0)
+ * @length: the length of the bit field
+ *
+ * Extract from the 8 bit input @value the bit field specified by the
+ * @start and @length parameters, and return it. The bit field must
+ * lie entirely within the 8 bit word. It is valid to request that
+ * all 8 bits are returned (ie @length 8 and @start 0).
+ *
+ * Returns: the value of the bit field extracted from the input value.
+ */
+static inline uint8_t extract8(uint8_t value, int start, int length)
+{
+    assert(start >= 0 && length > 0 && length <= 8 - start);
+    return (value >> start) & (~0U >> (32 - length));
+}
+
+/**
+ * extract16:
+ * @value: the value to extract the bit field from
+ * @start: the lowest bit in the bit field (numbered from 0)
+ * @length: the length of the bit field
+ *
+ * Extract from the 16 bit input @value the bit field specified by the
+ * @start and @length parameters, and return it. The bit field must
+ * lie entirely within the 16 bit word. It is valid to request that
+ * all 16 bits are returned (ie @length 16 and @start 0).
+ *
+ * Returns: the value of the bit field extracted from the input value.
+ */
+static inline uint16_t extract16(uint32_t value, int start, int length)
+{
+    assert(start >= 0 && length > 0 && length <= 16 - start);
+    return (value >> start) & (~0U >> (32 - length));
+}
+
+/**
  * extract64:
  * @value: the value to extract the bit field from
  * @start: the lowest bit in the bit field (numbered from 0)