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diff --git a/capstone/contrib/riscv_update/README.md b/capstone/contrib/riscv_update/README.md
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+# How to update RISCV tables.
+
+* Checkout LLVM. Patches are tested on commit `b81d715c`.
+  ```
+      git clone https://github.com/llvm/llvm-project.git
+      git checkout b81d715c
+  ```
+* Apply patches from the current directory.
+* Run tablegen.
+  ```
+      cd $LLVM
+      mkdir build
+      cd build
+      cmake -DCMAKE_CXX_FLAGS=-DCAPSTONE -DLLVM_EXPERIMENTAL_TARGETS_TO_BUILD="RISCV" ..
+      make RISCVCommonTableGen 
+   ```
+* Copy `.inc` files.
+  ```
+      cp arch/RISCV/RISCVGenInsnNameMaps.inc \
+         arch/RISCV/RISCVGenInsnNameMaps.inc.old
+      for inc in $(cd arch/RISCV && ls *.inc); do
+        cp $LLVM/build/lib/Target/RISCV/$inc arch/RISCV/
+      done
+  ```
+* Fixup `RISCVGenInsnNameMaps.inc`.
+  ```
+      comm -1 -3 \
+          <(grep RISCV_INS_ <arch/RISCV/RISCVGenInsnNameMaps.inc.old \
+            | sort -u) \
+          <(grep RISCV_INS_ <arch/RISCV/RISCVGenInsnNameMaps.inc \
+            | sort -u) \
+          >arch/RISCV/RISCVGenInsnNameMaps.inc.new
+      cat arch/RISCV/RISCVGenInsnNameMaps.inc.old \
+          arch/RISCV/RISCVGenInsnNameMaps.inc.new \
+          >arch/RISCV/RISCVGenInsnNameMaps.inc
+  ```
+* Add new groups, insns, registers and formats.
+  * `include/capstone/RISCV.h`
+    * `enum RISCV_insn`:
+      ```
+          comm -1 -3 \
+              <(perl -ne 'if (/(RISCV_INS_.+),/) { print "\t$1,\n" }' \
+                <include/capstone/RISCV.h | sort -u) \
+              <(perl -ne 'if (/(RISCV_INS_.+),/) { print "\t$1,\n" }' \
+                <arch/RISCV/RISCVMappingInsn.inc | sort -u)
+      ```
+    * `enum RISCV_insn_group`:
+      ```
+       perl -ne 'if (/(\{.RISCV_GRP_.*?\}),/) { print "\t$1,\n"; }' < \
+            arch/RISCV/RISCVMappingInsn.inc | sort -u          
+      ```
+  * `arch/RISCV/RISCVDisassembler.c`
+  * `arch/RISCV/RISCVInstPrinter.c`
+  * `arch/RISCV/RISCVMCTargetDesc.c`
+  * `arch/RISCV/RISCVMCTargetDesc.h`
+  * `arch/RISCV/RISCVMapping.c`
+    * `enum group_name_maps`:
+      ```
+          perl -ne 'if (/(RISCV_GRP_(.*?)),/) { print "\t{ $1, \"" . lc($2) . "\" },\n"; }' \
+              arch/RISCV/RISCVMappingInsn.inc | sort -u
+      ```