from mobile reslly bad spelling comment why layout should remain a fn

[ieee754fpu.git] / README.md

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@@ -4,8 +4,37 @@ 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).
 
+Developed under a Grant from NLnet (http://nlnet.nl), more information
+may be found at http://libre-soc.org
+
+# Requirements
+
+* nmigen
+* libresoc-nmutil
+* yosys (latest git repository, required by nmigen)
+* sfpy (running unit tests).  provides python bindings to berkeley softfloat-3
+
+# Building sfpy
+
+The standard sfpy will not work without being modified to the type of
+IEEE754 FP emulation being tested.  This FPU is emulating RISC-V, and
+there is some weirdness in x86 IEEE754 implementations when it comes
+to FP16 non-canonical NaNs.
+
+The following modifications are required to the sfpy berkeley-softfloat-3
+submodule:
+
+    cd /path/to/sfpy/berkeley-softfloat-3
+    git apply /path/to/ieee754fpu/berkeley-softfloat.patch
+
+The following modifications are required to the sfpy SoftPosit Makefile:
+
+    cd /path/to/sfpy/SoftPosit
+    git apply /path/to/ieee754fpu/SoftPosit.patch
+
 # Useful resources
 
 * https://en.wikipedia.org/wiki/IEEE_754-1985
 * http://weitz.de/ieee/
 * https://steve.hollasch.net/cgindex/coding/ieeefloat.html
+