add requirements (dependencies)

diff --git a/README.md b/README.md
index 638557b9ec21467f465be31d59a4adc3ab6845dc..dc09b92c64d641b3b8945e8469c4ffa3d734e454 100644 (file)
--- a/README.md
+++ b/README.md
@@ -4,6 +4,12 @@ This project implements a pipelined IEEE754 floating-point ALU that
 supports FP16, FP32 and FP64.  It is a general-purpose unit that
 may be used in any project (not limited to one specific processor).
 
+# Requirements
+
+* nmigen
+* yosys (latest git repository, required by nmigen)
+* sfpy (running unit tests).  provides python bindings to berkeley softfloat-3
+
 # Useful resources
 
 * https://en.wikipedia.org/wiki/IEEE_754-1985