X-Git-Url: https://git.libre-soc.org/?a=blobdiff_plain;f=src%2Fbase%2Fbitfield.hh;h=664093fa27fc96145ce16448afadf3264c7c3eee;hb=96936c6bf57b40c6da2582ad6dd1bdd0de2ea3db;hp=879780d5600c3cae37ecdf6874a41c4389194c83;hpb=ce4531c0794ee57c0029bc905802a7856832d941;p=gem5.git

diff --git a/src/base/bitfield.hh b/src/base/bitfield.hh
index 879780d56..664093fa2 100644
--- a/src/base/bitfield.hh
+++ b/src/base/bitfield.hh
@@ -44,6 +44,7 @@ mask(int nbits)
 }
 
 
+
 /**
  * Extract the bitfield from position 'first' to 'last' (inclusive)
  * from 'val' and right justify it.  MSB is numbered 63, LSB is 0.
@@ -57,6 +58,35 @@ bits(T val, int first, int last)
     return (val >> last) & mask(nbits);
 }
 
+/**
+ * Extract the bit from this position from 'val' and right justify it.
+ */
+template <class T>
+inline
+T
+bits(T val, int bit)
+{
+    return bits(val, bit, bit);
+}
+
+/**
+ * Mask off the given bits in place like bits() but without shifting.
+ * msb = 63, lsb = 0
+ */
+template <class T>
+inline
+T
+mbits(T val, int first, int last)
+{
+    return val & (mask(first+1) & ~mask(last));
+}
+
+inline uint64_t
+mask(int first, int last)
+{
+    return mbits((uint64_t)-1LL, first, last);
+}
+
 /**
  * Sign-extend an N-bit value to 64 bits.
  */
@@ -69,4 +99,66 @@ sext(uint64_t val)
     return sign_bit ? (val | ~mask(N)) : val;
 }
 
+/**
+ * Return val with bits first to last set to bit_val
+ */
+template <class T, class B>
+inline
+T
+insertBits(T val, int first, int last, B bit_val)
+{
+    T t_bit_val = bit_val;
+    T bmask = mask(first - last + 1) << last;
+    return ((t_bit_val << last) & bmask) | (val & ~bmask);
+}
+
+/**
+ * Overloaded for access to only one bit in value
+ */
+template <class T, class B>
+inline
+T
+insertBits(T val, int bit, B bit_val)
+{
+    return insertBits(val, bit, bit, bit_val);
+}
+
+/**
+ * A convenience function to replace bits first to last of val with bit_val
+ * in place.
+ */
+template <class T, class B>
+inline
+void
+replaceBits(T& val, int first, int last, B bit_val)
+{
+    val = insertBits(val, first, last, bit_val);
+}
+
+/** Overloaded function to allow to access only 1 bit*/
+template <class T, class B>
+inline
+void
+replaceBits(T& val, int bit, B bit_val)
+{
+    val = insertBits(val, bit, bit, bit_val);
+}
+/**
+ * Returns the bit position of the MSB that is set in the input
+ */
+inline
+int
+findMsbSet(uint64_t val) {
+    int msb = 0;
+    if (!val)
+        return 0;
+    if (bits(val, 63,32)) { msb += 32; val >>= 32; }
+    if (bits(val, 31,16)) { msb += 16; val >>= 16; }
+    if (bits(val, 15,8))  { msb += 8;  val >>= 8;  }
+    if (bits(val, 7,4))   { msb += 4;  val >>= 4;  }
+    if (bits(val, 3,2))   { msb += 2;  val >>= 2;  }
+    if (bits(val, 1,1))   { msb += 1; }
+    return msb;
+}
+
 #endif // __BASE_BITFIELD_HH__