[otbn] Define a slightly more general way to build code snippets
This Makefile fragment essentially defines a way to do:
foo.S -> foo.o -> foo.elf
However, you can now add dependencies and define $(otbn-libs) for an
specific ELF to allow one file to depend on another.
Signed-off-by: Rupert Swarbrick <rswarbrick@lowrisc.org>
diff --git a/sw/otbn/code-snippets/README.md b/sw/otbn/code-snippets/README.md
index eca8198..ef9b23e 100644
--- a/sw/otbn/code-snippets/README.md
+++ b/sw/otbn/code-snippets/README.md
@@ -11,3 +11,7 @@
instruction.
- `barrett384.S`: An example of a modular multiplication kernel based on
Barrett reduction.
+
+Also included in this directory is a Makefile fragment that can be
+used to assemble and link the snippets. This can be used standalone or
+included in another Makefile.
