diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 3c1f87b32d2..b898bf77f98 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2019-10-11  Jim Wilson  <jimw@sifive.com>
 
+	* gdbsupport/print-utils.h (pulongest): Fix comment.
+	(plongest): Likewise.
+	(phex): Add missing comment, mention leading zeros.
+	(phex_nz): Add mention of no leading zeros to comment.
+
 	* riscv-tdep.c (riscv_push_dummy_code): Change %lld to %s and use
 	plongest instead of unsigned long long cast.
 
diff --git a/gdb/gdbsupport/print-utils.h b/gdb/gdbsupport/print-utils.h
index 815b14cbed3..d52bcf8f611 100644
--- a/gdb/gdbsupport/print-utils.h
+++ b/gdb/gdbsupport/print-utils.h
@@ -24,20 +24,23 @@
    cell.  */
 #define PRINT_CELL_SIZE 50
 
-/* %d for LONGEST.  The result is stored in a circular static buffer,
+/* %u for ULONGEST.  The result is stored in a circular static buffer,
    NUMCELLS deep.  */
 
 extern char *pulongest (ULONGEST u);
 
-/* %u for ULONGEST.  The result is stored in a circular static buffer,
+/* %d for LONGEST.  The result is stored in a circular static buffer,
    NUMCELLS deep.  */
 
 extern char *plongest (LONGEST l);
 
+/* Convert a ULONGEST into a HEX string, like %lx, with leading zeros.
+   The result is stored in a circular static buffer, NUMCELLS deep.  */
+
 extern char *phex (ULONGEST l, int sizeof_l);
 
-/* Convert a ULONGEST into a HEX string, like %lx.  The result is
-   stored in a circular static buffer, NUMCELLS deep.  */
+/* Convert a ULONGEST into a HEX string, like %lx, without leading zeros.
+   The result is  stored in a circular static buffer, NUMCELLS deep.  */
 
 extern char *phex_nz (ULONGEST l, int sizeof_l);