From 791fb3d7a58b86e5f30229625dfd33659f33fd6e Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Mon, 31 Jul 2017 11:22:21 +0200 Subject: [PATCH] Fix documentation about rot agent expression bytecode The rot agent expression bytecode rotates the three items on the top of the stack. It is not clear which way the rotation is. However, the documentation currently shows this as the effect of the instructions: a b c => c b a which doesn't make sense, since the value b doesn't move. The two valid possibilities I see are a b c => b c a a b c => c a b depending on which way you rotate. When looking at the gdbserver code, the top of the stack becomes the third item, and the next-to-top item becomes the top. So the second form would be the right one, since in this notation the top of the stack is the rightmost element: a b c => c a b I adjusted the symbolic description and added a bit of text to make it more obvious. gdb/doc/ChangeLog: * agentexpr.texi (rot): Fix symbolic description, improve textual description. --- gdb/doc/ChangeLog | 5 +++++ gdb/doc/agentexpr.texi | 6 ++++-- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog index d43ae35c00..6a3d0610a2 100644 --- a/gdb/doc/ChangeLog +++ b/gdb/doc/ChangeLog @@ -1,3 +1,8 @@ +2017-07-31 Simon Marchi + + * agentexpr.texi (rot): Fix symbolic description, improve + textual description. + 2017-07-26 Yao Qi * gdb.texinfo (Maintenance Commands): Document command diff --git a/gdb/doc/agentexpr.texi b/gdb/doc/agentexpr.texi index 5668e9c1e4..081e5fa68b 100644 --- a/gdb/doc/agentexpr.texi +++ b/gdb/doc/agentexpr.texi @@ -396,8 +396,10 @@ is zero, this is the same as @code{dup}; if @var{n} is one, it copies 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