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diff --git a/openpower/sv/branches.mdwn b/openpower/sv/branches.mdwn
index e34f40a4b724235131f907a04495c12ea0bd7116..a145e36125737a16afbe5938eda3a3cb53785b6c 100644 (file)
--- a/openpower/sv/branches.mdwn
+++ b/openpower/sv/branches.mdwn
@@ -16,14 +16,18 @@ Links
 * [[openpower/isa/branch]]
 
 Scalar 3.0B Branch Conditional operations, `bc`, `bctar` etc. test a
-Condition Register.  When doing so in a Vector Context, it is quite
-reasonable and logical to test and Branch on a *Vector* of CR Fields
+Condition Register.  However for parallel processing it is simply impossible
+to perform multiple independent branches: the Program Counter simply
+cannot branch to multiple destinations based on multiple conditions.
+The best that can be done is
+to test multiple Conditions and make a decision of a *single* branch,
+based on analysis of a *Vector* of CR Fields
 which have just been calculated from a *Vector* of results. In 3D Shader
 binaries, which are inherently parallelised and predicated, testing all or
 some results and branching based on multiple tests is extremely common,
 and a fundamental part of Shader Compilers.  Therefore, `sv.bc` and
 other Vector-aware Branch Conditional instructions are a high priority
-for 3D GPUs.
+for 3D GPU workloads.
 
 The `BI` field of Branch Conditional operations is five bits, in scalar
 v3.0B this would select one bit of the 32 bit CR.  In SVP64 there are
@@ -32,7 +36,7 @@ v3.0B this would select one bit of the 32 bit CR.  In SVP64 there are
 are extended to either scalar or vector and to select CR Fields 0..127
 as specified in SVP64 [[sv/svp64/appendix]].
 
-When considering an "array" of branches, there are four useful modes:
+When considering an "array" of branch-tests, there are four useful modes:
 AND, OR, NAND and NOR of all Conditions.
 NAND and NOR may be synthesised by
 inverting `BO[2]` which just leaves two modes: