X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=include%2Fbitfield.h;h=a59f3c279aadc3583a837e53acfe747f8a698d7a;hb=3d47b2d741683023de05f08f9adb4bd25c189c46;hp=ec4815c8e05179508c00cce24655acd7382ba62e;hpb=fae56934a0744a4dd6981323ba8a966646fd7ca5;p=oweals%2Fu-boot.git

diff --git a/include/bitfield.h b/include/bitfield.h
index ec4815c8e0..a59f3c279a 100644
--- a/include/bitfield.h
+++ b/include/bitfield.h
@@ -27,6 +27,12 @@
  * old = bitfield_extract(old_reg_val, 10, 5);
  * new_reg_val = bitfield_replace(old_reg_val, 10, 5, new);
  *
+ * or
+ *
+ * mask = bitfield_mask(10, 5);
+ * old = bitfield_extract_by_mask(old_reg_val, mask);
+ * new_reg_val = bitfield_replace_by_mask(old_reg_val, mask, new);
+ *
  * The numbers 10 and 5 could for example come from data
  * tables which describe all bitfields in all registers.
  */
@@ -54,5 +60,31 @@ static inline uint bitfield_replace(uint reg_val, uint shift, uint width,
 {
 	uint mask = bitfield_mask(shift, width);
 
-	return (reg_val & ~mask) | (bitfield_val << shift);
+	return (reg_val & ~mask) | ((bitfield_val << shift) & mask);
+}
+
+/* Produces a shift of the bitfield given a mask */
+static inline uint bitfield_shift(uint mask)
+{
+	return mask ? ffs(mask) - 1 : 0;
+}
+
+/* Extract the value of a bitfield found within a given register value */
+static inline uint bitfield_extract_by_mask(uint reg_val, uint mask)
+{
+	uint shift = bitfield_shift(mask);
+
+	return (reg_val & mask) >> shift;
+}
+
+/*
+ * Replace the value of a bitfield found within a given register value
+ * Returns the newly modified uint value with the replaced field.
+ */
+static inline uint bitfield_replace_by_mask(uint reg_val, uint mask,
+					    uint bitfield_val)
+{
+	uint shift = bitfield_shift(mask);
+
+	return (reg_val & ~mask) | ((bitfield_val << shift) & mask);
 }