cstool: update README
diff --git a/cstool/README b/cstool/README
index 65479cb..71c21f8 100644
--- a/cstool/README
+++ b/cstool/README
@@ -22,5 +22,21 @@
$ cstool x32 "90+91"
$ cstool x32 "90:91"
-To see all the supported options, run ./cstool
+To print out instruction details, run Cstool with -d option, like below.
+ $ cstool -d x32 "01 d8"
+ 0 01d8 add eax, ebx
+ Prefix:0x00 0x00 0x00 0x00
+ Opcode:0x01 0x00 0x00 0x00
+ rex: 0x0
+ addr_size: 4
+ modrm: 0xd8
+ disp: 0x0
+ sib: 0x0
+ op_count: 2
+ operands[0].type: REG = eax
+ operands[0].size: 4
+ operands[1].type: REG = ebx
+ operands[1].size: 4
+
+To see all the supported options, run ./cstool
