@c This file is part of the GDB manual.
@c
-@c Copyright (C) 2003-2015 Free Software Foundation, Inc.
+@c Copyright (C) 2003-2019 Free Software Foundation, Inc.
@c
@c See the file gdb.texinfo for copying conditions.
@item @code{zero_ext} (0x2a) @var{n}: @var{a} @result{} @var{a}, zero-extended from @var{n} bits
Pop an unsigned value from the stack; zero all but the bottom @var{n}
-bits. This means that all bits to the left of bit @var{n-1} (where the
-least significant bit is bit 0) are set to the value of bit @var{n-1}.
+bits.
The number of source bits to preserve, @var{n}, is encoded as a single
byte unsigned integer following the @code{zero_ext} bytecode.
the item under the top item, etc. If @var{n} exceeds the number of
items on the stack, terminate with an error.
-@item @code{rot} (0x33): @var{a} @var{b} @var{c} => @var{c} @var{b} @var{a}
-Rotate the top three items on the stack.
+@item @code{rot} (0x33): @var{a} @var{b} @var{c} => @var{c} @var{a} @var{b}
+Rotate the top three items on the stack. The top item (c) becomes the third
+item, the next-to-top item (b) becomes the top item and the third item (a) from
+the top becomes the next-to-top item.
@item @code{if_goto} (0x20) @var{offset}: @var{a} @result{}
Pop an integer off the stack; if it is non-zero, branch to the given