+/*
+ * Perform the instruction that we overwrote with a breakpoint. As we
+ * don't have a single-step facility, this means we have to:
+ * - put the instruction back
+ * - put a second breakpoint at the following instruction,
+ * set after_breakpoint and continue execution.
+ *
+ * When the second breakpoint is hit (very shortly thereafter, we hope)
+ * sigtrap_handler gets called again, but follows the AfterBreakpoint
+ * arm, which
+ * - puts a bpt back in the first breakpoint place (running across a
+ * breakpoint shouldn't cause it to be uninstalled)
+ * - replaces the second bpt with the instruction it was meant to be
+ * - carries on
+ *
+ * Clear?
+ */
+static unsigned int *skipped_break_addr, displaced_after_inst;