From: José Fonseca <jfonseca@vmware.com>
Date: Wed, 20 Jul 2011 21:53:59 +0000 (-0700)
Subject: gallivm: Add a note about log2 computation and denormalized numbers.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=5161aff48af2fe0171be06fc727a000ad300fbd9;p=mesa.git

gallivm: Add a note about log2 computation and denormalized numbers.
---

diff --git a/src/gallium/auxiliary/gallivm/lp_bld_arit.c b/src/gallium/auxiliary/gallivm/lp_bld_arit.c
index 0c075bafb2c..2be8598704e 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_arit.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_arit.c
@@ -2465,6 +2465,12 @@ lp_build_log2_approx(struct lp_build_context *bld,
 
       assert(type.floating && type.width == 32);
 
+      /* 
+       * We don't explicitly handle denormalized numbers. They will yield a
+       * result in the neighbourhood of -127, which appears to be adequate
+       * enough.
+       */
+
       i = LLVMBuildBitCast(builder, x, int_vec_type, "");
 
       /* exp = (float) exponent(x) */