[Mesa-dev] [PATCH 5/8] util: Precompute channel shifts in u_format_parse.py

[Richard Sandiford]

Store the shift value for a bitmask channel in the Channel object,
rather than working it out on the fly.  This allows the shift to
depend on endianness.

There is no change to the generated u_format_table.c.

Signed-off-by: Richard Sandiford <rsandifo at linux.vnet.ibm.com>
---
 src/gallium/auxiliary/util/u_format_pack.py  | 8 ++------
 src/gallium/auxiliary/util/u_format_parse.py | 5 +++++
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/gallium/auxiliary/util/u_format_pack.py b/src/gallium/auxiliary/util/u_format_pack.py
index 84eef8c..b4db0d1 100644
--- a/src/gallium/auxiliary/util/u_format_pack.py
+++ b/src/gallium/auxiliary/util/u_format_pack.py
@@ -428,9 +428,9 @@ def generate_unpack_kernel(format, dst_channel, dst_native_type):
             print '#endif'
 
         # Compute the intermediate unshifted values 
-        shift = 0
         for i in range(4):
             src_channel = channels[i]
+            shift = src_channel.shift
             value = 'value'
             if src_channel.type == UNSIGNED:
                 if shift:
@@ -454,8 +454,6 @@ def generate_unpack_kernel(format, dst_channel, dst_native_type):
             if value is not None:
                 print '         %s = %s;' % (src_channel.name, value)
                 
-            shift += src_channel.size
-
         # Convert, swizzle, and store final values
         for i in range(4):
             swizzle = swizzles[i]
@@ -529,9 +527,9 @@ def generate_pack_kernel(format, src_channel, src_native_type):
         depth = format.block_size()
         print '         uint%u_t value = 0;' % depth 
 
-        shift = 0
         for i in range(4):
             dst_channel = channels[i]
+            shift = dst_channel.shift
             if inv_swizzle[i] is not None:
                 value ='src[%u]' % inv_swizzle[i]
                 dst_colorspace = format.colorspace
@@ -555,8 +553,6 @@ def generate_pack_kernel(format, src_channel, src_native_type):
                 if value is not None:
                     print '         value |= %s;' % (value)
                 
-            shift += dst_channel.size
-
         if depth > 8:
             print '#ifdef PIPE_ARCH_BIG_ENDIAN'
             print '         value = util_bswap%u(value);' % depth
diff --git a/src/gallium/auxiliary/util/u_format_parse.py b/src/gallium/auxiliary/util/u_format_parse.py
index 2553a5b..d60a0a2 100755
--- a/src/gallium/auxiliary/util/u_format_parse.py
+++ b/src/gallium/auxiliary/util/u_format_parse.py
@@ -337,6 +337,11 @@ def parse(filename):
         swizzles = [_swizzle_parse_map[swizzle] for swizzle in fields[8]]
         channels = _parse_channels(fields[4:8], layout, colorspace, swizzles)
 
+        shift = 0
+        for channel in channels:
+            channel.shift = shift
+            shift += channel.size
+
         format = Format(name, layout, block_width, block_height, channels, swizzles, colorspace)
         formats.append(format)
     return formats
-- 
1.7.11.7