File u_gallivm-correct-channel-shift-logic-on-big-en... of Package Mesa

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File u_gallivm-correct-channel-shift-logic-on-big-endian.patch of Package Mesa (Revision ffcbbe7cc9e88870dc4c91327f503126)

Currently displaying revision ffcbbe7cc9e88870dc4c91327f503126 , Show latest

From ab0e1e38ab9e8b23602af21d1b43e98afbf80e45 Mon Sep 17 00:00:00 2001
From: Ray Strode <rstrode@redhat.com>
Date: Fri, 21 Apr 2017 15:22:14 -0400
Subject: [PATCH] gallivm: correct channel shift logic on big endian

lp_build_fetch_rgba_soa fetches a texel from a texture.
Part of that process involves first gathering the element
together from memory into a packed format, and then breaking
out the individual color channels into separate, parallel
arrays.

The code fails to account for endianess when reading the packed
values.

This commit attempts to correct the problem by reversing the order
the packed values are read on big endian systems.
---
 src/gallium/auxiliary/gallivm/lp_bld_format_soa.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/gallium/auxiliary/gallivm/lp_bld_format_soa.c b/src/gallium/auxiliary/gallivm/lp_bld_format_soa.c
index 98eb694..22c19b1 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_format_soa.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_format_soa.c
@@ -650,7 +650,13 @@ lp_build_fetch_rgba_soa(struct gallivm_state *gallivm,
          for (i = 0; i < format_desc->nr_channels; i++) {
             struct util_format_channel_description chan_desc = format_desc->channel[i];
             unsigned blockbits = type.width;
-            unsigned vec_nr = chan_desc.shift / type.width;
+            unsigned vec_nr;
+
+#ifdef PIPE_ARCH_BIG_ENDIAN
+            vec_nr = (format_desc->block.bits - (chan_desc.shift + chan_desc.size)) / type.width;
+#else
+            vec_nr = chan_desc.shift / type.width;
+#endif
             chan_desc.shift %= type.width;
 
             output[i] = lp_build_extract_soa_chan(&bld,
-- 
1.8.3.1

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File u_gallivm-correct-channel-shift-logic-on-big-endian.patch of Package Mesa (Revision ffcbbe7cc9e88870dc4c91327f503126)

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