From: Jeremy Kerr <jk@ozlabs.org>
Date: Wed, 22 Nov 2006 03:34:24 +0000 (+1100)
Subject: Add support for mask<<shift field definitions
X-Git-Url: https://git.ozlabs.org/?a=commitdiff_plain;h=d62329bba2c211aaa2b1cf088a35637f16297c87;p=bitfield

Add support for mask<<shift field definitions

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
---

diff --git a/ChangeLog b/ChangeLog
index 79dbd74..f072e44 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,6 @@
 version ??
 	* Allow alternate (bit 0 is lsb) bit numbering scheme
+	* Add support for mask<<shift field definitions
 
 version 0.2:
 	* Add support for aliased definitions.
diff --git a/bitfield b/bitfield
index 3b34aeb..8bb8d35 100644
--- a/bitfield
+++ b/bitfield
@@ -48,6 +48,15 @@ class bitfield:
 			return self.values[value]
 		return None
 
+	@staticmethod
+	def mask_and_shift_to_bits(width, mask, shift):
+		bits = []
+		val = mask << shift
+		for i in range(0, width):
+			if mask & (1 << i):
+				bits.append(width - i - 1 - shift)
+		return bits
+
 	@staticmethod
 	def parse_bitfield(line, reg):
 		a = line.split(None, 1)
@@ -58,15 +67,24 @@ class bitfield:
 		bits = []
 		for s in range_str.split(','):
 			if ':' in s:
-				(start, end) = s.split(':')
+				(start, end) = map( \
+					lambda s: reg.bit_number(int(s)),
+					s.split(':'))
 				start = reg.bit_number(int(start))
 				end = reg.bit_number(int(end))
 				bits.extend(range(start, end + 1, 1))
+			elif '<<' in s:
+				(mask, shift) = map(lambda s: int(s.strip()),
+					s.split('<<'))
+				bits.extend(bitfield.mask_and_shift_to_bits( \
+					reg.width, mask, shift))
 			else:
 				bits.append(reg.bit_number(int(s)))
  
 		return bitfield(bits, name)
 
+
+
 	@staticmethod
 	def parse_value(line):
 		a = line.split(None, 1)