add proposed frsqrt instruction encoding table

diff --git a/doc/frsqrt.rst b/doc/frsqrt.rst
new file mode 100644 (file)
index 0000000..c2c07fb
--- /dev/null
+++ b/doc/frsqrt.rst
@@ -0,0 +1,14 @@
+Proposed frsqrt Instruction Encoding
+====================================
+
++-----------+---------+-------+-----+--------+----+---------+
+| Mnemonic  | funct7  | rs2   | rs1 | funct3 | rd | opcode  |
++===========+=========+=======+=====+========+====+=========+
+| frsqrt.s  | 0111100 | 00000 | rs1 | rm     | rd | 1010011 |
++-----------+---------+-------+-----+--------+----+---------+
+| frsqrt.d  | 0111101 | 00000 | rs1 | rm     | rd | 1010011 |
++-----------+---------+-------+-----+--------+----+---------+
+| frsqrt.q  | 0111110 | 00000 | rs1 | rm     | rd | 1010011 |
++-----------+---------+-------+-----+--------+----+---------+
+| frsqrt.h  | 0111111 | 00000 | rs1 | rm     | rd | 1010011 |
++-----------+---------+-------+-----+--------+----+---------+