doc: exception command

Create man-page for exception command.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

doc/usage/exception.rst

@@ -0,0 +1,68 @@
+exception command
+=================
+
+Synopsis
+--------
+
+::
+
+    exception <type>
+
+Description
+-----------
+
+The exception command is used to test the handling of exceptions like undefined
+instructions, segmentation faults or alignment faults.
+
+type
+  type of exception to be generated. The available types are architecture
+  dependent. Use 'help exception' to determine which are available.
+
+  **ARM:**
+
+  breakpoint
+    prefetch abort
+
+  unaligned
+    data abort
+
+  undefined
+    undefined instruction
+
+  **RISC-V:**
+
+  unaligned
+    load address misaligned
+
+  undefined
+    undefined instruction
+
+  **Sandbox:**
+
+  sigsegv
+    illegal memory access
+
+  undefined
+    undefined instruction
+
+  **x86:**
+
+  undefined
+    undefined instruction
+
+Examples
+--------
+
+::
+
+    => exception undefined
+
+    Illegal instruction
+    pc = 0x56076dd1a0f9, pc_reloc = 0x540f9
+
+    resetting ...
+
+Return value
+------------
+
+The return value $? is always set to 0 (true).

doc/usage/index.rst

@@ -19,6 +19,7 @@ Shell commands
    button
    conitrace
    echo
+   exception
    exit
    false
    for