Improved rationale for AMO selection.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/a.tex b/src/a.tex
index 8c3c745..e4e20ed 100644
--- a/src/a.tex
+++ b/src/a.tex
@@ -319,6 +319,12 @@ microarchitecture can implement AMOs using the LR/SC primitives.  More
 complex implementations might also implement AMOs at memory
 controllers, and can optimize away fetching the original value when
 the destination is {\tt x0}.
+
+The set of AMOs was chosen to support the C11/C+11 atomic memory
+operations efficiently, and also to support parallel reductions in
+memory.  Another use of AMOs is to provide atomic updates to
+memory-mapped device registers (e..g, setting, clearing, or toggling
+bits) in the I/O space.
 \end{commentary}
 
 To help implement multiprocessor synchronization, the AMOs optionally