Add doc/gdb

doc/gdb

@@ -9,3 +9,52 @@ Running gdbserver
 Connecting from r2
 ------------------
         $Write failed: Host is down5
+
+Support implementations
+===========
+r2 have support for connecting to remote GDB instances:
+
+                x86-32   x86-64   arm    arm64   sh
+    winedbg       x        x       -      -      -
+    qemu          x        x       ?      x      -
+    gdbserver     x        x       ?      ?      ?
+
+    x = supported
+    ? = untested
+    - = not supported
+
+Supported Commands
+------------------
+- read/write memory
+
+Writing or reading memory is implemented through the m/M packet.
+
+- read registers
+
+Reading registers is currently implemented through the <g> packet of the gdb protocol.
+It returns the whole register profile at once. 
+
+- write registers
+
+There are two ways of writing registers. The first one is through the P packet.
+It works like this: `P<register_index>=<register_value>`
+The second one is the G packet, that writes the whole register Profile at once.
+The implementation first tries to use the newer P packet and if it receives a $00# packet (that says not implemented), it tries to write through the G packet.
+
+- stepping (but this is still the softstep mode and for an unknown reason it sill does not call th gdb_write_register function)
+
+Supported Packets:
+- g : Reads the whole register Profile at once
+- G : Writes the whole register Profile at once
+- m : Reads memory 
+- M : Writes memory
+- vCont,v : continues execution of the binary
+- P : Write one register
+
+TODO
+----
+- Implement GDBserver to allow other apps use r2 debugger 
+- Fix that usese the gdb internal stepping version
+- Fix softstep, that it finally recoils correct (it just have to reset the eip/rip)
+- Add Breakpoints (should be an easy add of the function, because its already implemented in the gdb lib)
+