mirror of
https://github.com/espressif/binutils-gdb.git
synced 2025-06-24 20:28:28 +08:00
0e6a6e40bb
There's a comment in riscv-tdep.c that explains some of the background about how we check for the fcsr, fflags, and frm registers within a riscv target description. This comment (and the functionality it describes) relates to how QEMU advertises these registers within its target description. Unfortunately, QEMU includes these three registers in both the fpu and crs target description features. To work around this GDB uses one of the register declarations, and ignores the other, this means the GDB user sees a single copy of each register, and things just work. When I originally wrote the comment I thought it didn't matter which copy of the register GDB selected, the fpu copy or the csr copy, so long as we just used one of them. The comment reflected this belief. Upon further investigation, it turns out I was wrong. GDB has to use the csr copy of the register. If GDB tries to use the register from the fpu feature then QEMU will return an error when GDB tries to read or write the register. Luckily, the code within GDB (currently) will always select the csr copy of the register, so nothing is broken, but the comment is wrong. This commit updates the comment to better describe what is actually going on. Of course, I should probably also send a patch to QEMU to fix up the target description that is sent to GDB.
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.