diff --git a/gdb/gdbserver/i386-low.c b/gdb/gdbserver/i386-low.c
index 304d6f3..d122ff7 100644
--- a/gdb/gdbserver/i386-low.c
+++ b/gdb/gdbserver/i386-low.c
@@ -21,6 +21,17 @@
 #include "target.h"
 #include "i386-low.h"
 
+/* Support for hardware watchpoints and breakpoints using the i386
+   debug registers.
+
+   This provides several functions for inserting and removing
+   hardware-assisted breakpoints and watchpoints, testing if one or
+   more of the watchpoints triggered and at what address, checking
+   whether a given region can be watched, etc.
+
+   The functions below implement debug registers sharing by reference
+   counts, and allow to watch regions up to 16 bytes long.  */
+
 /* Support for 8-byte wide hw watchpoints.  */
 #ifndef TARGET_HAS_DR_LEN_8
 /* NOTE: sizeof (long) == 4 on win64.  */
@@ -156,8 +167,7 @@ i386_low_init_dregs (struct i386_debug_reg_state *state)
   state->dr_status_mirror  = 0;
 }
 
-/* Print the values of the mirrored debug registers.  This is enabled via
-   the "set debug-hw-points 1" monitor command.  */
+/* Print the values of the mirrored debug registers.  */
 
 static void
 i386_show_dr (struct i386_debug_reg_state *state,
@@ -427,7 +437,7 @@ i386_update_inferior_debug_regs (struct i386_debug_reg_state *inf_state,
 
 /* Insert a watchpoint to watch a memory region which starts at
    address ADDR and whose length is LEN bytes.  Watch memory accesses
-   of the type TYPE_FROM_PACKET.  Return 0 on success, -1 on failure.  */
+   of the type TYPE.  Return 0 on success, -1 on failure.  */
 
 int
 i386_low_insert_watchpoint (struct i386_debug_reg_state *state,
@@ -523,8 +533,8 @@ i386_low_region_ok_for_watchpoint (struct i386_debug_reg_state *state,
 }
 
 /* If the inferior has some break/watchpoint that triggered, set the
-   address associated with that break/watchpoint and return true.
-   Otherwise, return false.  */
+   address associated with that break/watchpoint and return non-zero.
+   Otherwise, return zero.  */
 
 int
 i386_low_stopped_data_address (struct i386_debug_reg_state *state,
@@ -603,8 +613,8 @@ i386_low_stopped_data_address (struct i386_debug_reg_state *state,
   return rc;
 }
 
-/* Return true if the inferior has some watchpoint that triggered.
-   Otherwise return false.  */
+/* Return non-zero if the inferior has some watchpoint that triggered.
+   Otherwise return zero.  */
 
 int
 i386_low_stopped_by_watchpoint (struct i386_debug_reg_state *state)
diff --git a/gdb/gdbserver/i386-low.h b/gdb/gdbserver/i386-low.h
index 8d8e73f..681ade0 100644
--- a/gdb/gdbserver/i386-low.h
+++ b/gdb/gdbserver/i386-low.h
@@ -32,9 +32,9 @@
 /* Debug registers' indices.  */
 #define DR_FIRSTADDR 0
 #define DR_LASTADDR  3
-#define DR_NADDR     4 /* The number of debug address registers.  */
-#define DR_STATUS    6
-#define DR_CONTROL   7
+#define DR_NADDR     4	/* The number of debug address registers.  */
+#define DR_STATUS    6	/* Index of debug status register (DR6).  */
+#define DR_CONTROL   7	/* Index of debug control register (DR7).  */
 
 /* Global state needed to track h/w watchpoints.  */
 
diff --git a/gdb/i386-nat.c b/gdb/i386-nat.c
index f9fb52f..a7742f2 100644
--- a/gdb/i386-nat.c
+++ b/gdb/i386-nat.c
@@ -37,6 +37,7 @@
    The functions below implement debug registers sharing by reference
    counts, and allow to watch regions up to 16 bytes long.  */
 
+/* Low-level function vector.  */
 struct i386_dr_low_type i386_dr_low;
 
 /* Support for 8-byte wide hw watchpoints.  */
@@ -265,9 +266,7 @@ i386_cleanup_dregs (void)
   i386_forget_process (ptid_get_pid (inferior_ptid));
 }
 
-/* Print the values of the mirrored debug registers.  This is called
-   when maint_show_dr is non-zero.  To set that up, type "maint
-   show-debug-regs" at GDB's prompt.  */
+/* Print the values of the mirrored debug registers.  */
 
 static void
 i386_show_dr (struct i386_debug_reg_state *state,
@@ -439,7 +438,7 @@ i386_remove_aligned_watchpoint (struct i386_debug_reg_state *state,
 	  && state->dr_mirror[i] == addr
 	  && I386_DR_GET_RW_LEN (state->dr_control_mirror, i) == len_rw_bits)
 	{
-	  if (--state->dr_ref_count[i] == 0) /* no longer in use?  */
+	  if (--state->dr_ref_count[i] == 0) /* No longer in use?  */
 	    {
 	      /* Reset our mirror.  */
 	      state->dr_mirror[i] = 0;
@@ -646,8 +645,8 @@ i386_region_ok_for_watchpoint (struct target_ops *self,
   return nregs <= DR_NADDR ? 1 : 0;
 }
 
-/* If the inferior has some watchpoint that triggered, set the
-   address associated with that watchpoint and return non-zero.
+/* If the inferior has some break/watchpoint that triggered, set the
+   address associated with that break/watchpoint and return non-zero.
    Otherwise, return zero.  */
 
 static int
@@ -668,24 +667,25 @@ i386_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
   unsigned control = 0;
 
   /* In non-stop/async, threads can be running while we change the
-     STATE (and friends).  Say, we set a watchpoint, and let threads
-     resume.  Now, say you delete the watchpoint, or add/remove
-     watchpoints such that STATE changes while threads are running.
-     On targets that support non-stop, inserting/deleting watchpoints
-     updates the STATE only.  It does not update the real thread's
-     debug registers; that's only done prior to resume.  Instead, if
-     threads are running when the mirror changes, a temporary and
-     transparent stop on all threads is forced so they can get their
-     copy of the debug registers updated on re-resume.  Now, say,
-     a thread hit a watchpoint before having been updated with the new
-     STATE contents, and we haven't yet handled the corresponding
-     SIGTRAP.  If we trusted STATE below, we'd mistake the real
-     trapped address (from the last time we had updated debug
-     registers in the thread) with whatever was currently in STATE.
-     So to fix this, STATE always represents intention, what we _want_
-     threads to have in debug registers.  To get at the address and
-     cause of the trap, we need to read the state the thread still has
-     in its debug registers.
+     global dr_mirror (and friends).  Say, we set a watchpoint, and
+     let threads resume.  Now, say you delete the watchpoint, or
+     add/remove watchpoints such that dr_mirror changes while threads
+     are running.  On targets that support non-stop,
+     inserting/deleting watchpoints updates the global dr_mirror only.
+     It does not update the real thread's debug registers; that's only
+     done prior to resume.  Instead, if threads are running when the
+     mirror changes, a temporary and transparent stop on all threads
+     is forced so they can get their copy of the debug registers
+     updated on re-resume.  Now, say, a thread hit a watchpoint before
+     having been updated with the new dr_mirror contents, and we
+     haven't yet handled the corresponding SIGTRAP.  If we trusted
+     dr_mirror below, we'd mistake the real trapped address (from the
+     last time we had updated debug registers in the thread) with
+     whatever was currently in dr_mirror.  So to fix this, dr_mirror
+     always represents intention, what we _want_ threads to have in
+     debug registers.  To get at the address and cause of the trap, we
+     need to read the state the thread still has in its debug
+     registers.
 
      In sum, always get the current debug register values the current
      thread has, instead of trusting the global mirror.  If the thread
@@ -727,6 +727,9 @@ i386_stopped_data_address (struct target_ops *ops, CORE_ADDR *addr_p)
   return rc;
 }
 
+/* Return non-zero if the inferior has some watchpoint that triggered.
+   Otherwise return zero.  */
+
 static int
 i386_stopped_by_watchpoint (struct target_ops *ops)
 {
