From b7d2fe148e7662875b9d64c0d1e25fa853d26b5e Mon Sep 17 00:00:00 2001 From: Tom Tromey Date: Thu, 24 Oct 2019 10:30:13 -0600 Subject: [PATCH] Document m68k floating point feature correspondence From what I can tell, The m68k floating point target feature should apparently always be called "org.gnu.gdb.coldfire.fp" -- even when the primary feature is not "coldfire", because m68k_gdbarch_init only checks for this feature when assigning register numbers. However, the floating point registers are expected to match what gdb thinks are the register sizes for the primary feature. For example, if the main feature is "coldfire", then the floating point registers should be 64 bits. See this note for some an instance of this confusion: https://lists.gnu.org/archive/html/qemu-devel/2017-06/msg04564.html This patch documents the oddity. Let me know what you think. An alternate approach here might be to make gdb adapt to the register sizes as actually reported. I'm not sure if this makes sense or not. gdb/doc/ChangeLog 2020-01-26 Tom Tromey * gdb.texinfo (M68K Features): Document floating-point feature correspondence. Change-Id: I4cd86acbe3449a29ce38327524c508c206b25b8f --- gdb/doc/ChangeLog | 5 +++++ gdb/doc/gdb.texinfo | 6 ++++++ 2 files changed, 11 insertions(+) diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog index 139951f48c2..49004802003 100644 --- a/gdb/doc/ChangeLog +++ b/gdb/doc/ChangeLog @@ -1,3 +1,8 @@ +2020-01-26 Tom Tromey + + * gdb.texinfo (M68K Features): Document floating-point feature + correspondence. + 2020-01-25 Philippe Waroquiers * gdb.texinfo (Attach): Document the new option and the diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index 2a38b03f33e..a2866a28333 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -45230,6 +45230,12 @@ used. The feature that is present should contain registers This feature is optional. If present, it should contain registers @samp{fp0} through @samp{fp7}, @samp{fpcontrol}, @samp{fpstatus} and @samp{fpiaddr}. + +Note that, despite the fact that this feature's name says +@samp{coldfire}, it is used to describe any floating point registers. +The size of the registers must match the main m68k flavor; so, for +example, if the primary feature is reported as @samp{coldfire}, then +64-bit floating point registers are required. @end table @node NDS32 Features -- 2.30.2