Add compilation steps to README.md

Authored-by: Joydeep Tripathy <[email protected]>

README.md

@@ -354,6 +354,10 @@ There is also (as yet unmerged) support for [integration with riscv-config](http
 For booting operating system images, see the information under the
 [os-boot/](os-boot/) subdirectory.
 
+### How to use the out-of-tree JSON backend to generate JSON from Sail
+
+For details, see [JSON.md](doc/JSON.md).
+
 ### Using development versions of Sail
 
 Rarely, the version of Sail packaged in opam may not meet your needs. This could happen if you need a bug fix or new feature not yet in the released Sail version, or you are actively working on Sail. In this case you can tell the `sail-riscv` `Makefile` to use a local copy of Sail by setting `SAIL_DIR` to the root of a checkout of the Sail repo when you invoke `make`. Alternatively, you can use `opam pin` to install Sail from a local checkout of the Sail repo as described in the Sail installation instructions.

doc/JSON.md

@@ -0,0 +1,18 @@
+STEPS TO BUILD AND COMPILE THE PROJECT
+=======================================
+
+After Installing the prerequisites
+
+1.  We first need to build the sail parser.
+    1. Find a directory to clone this repository, and make that directory your current working directory.
+    2. `git clone https://github.com/ThinkOpenly/sail`
+    3. `cd sail`
+    4. `make`
+
+2.  Then, set up the environment for building in the RISC-V Sail repository:
+    1. `eval $(opam env)`
+    2. `export PATH=<path-to-sail-repository>:$PATH`
+
+3.  Clone this sail-riscv repository.
+
+4.  Within that clone : `make json`