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Re: PATCH: ARMV7M support
- From: "Shaun Jackman" <sjackman at gmail dot com>
- To: mark at codesourcery dot com
- Cc: newlib at sources dot redhat dot com
- Date: Thu, 23 Mar 2006 14:50:53 -0700
- Subject: Re: PATCH: ARMV7M support
- References: <200603232014.k2NKEr7h007285@sethra.codesourcery.com>
- Reply-to: "Shaun Jackman" <sjackman at gmail dot com>
On 3/23/06, Mark Mitchell <email@example.com> wrote:
> This patch adds support for ARM V7M bare metal hardware to Newlib.
> Here are the changes:
Can you seperate the bare-metal and dependency (_exit and stdio)
component from the ARMv7M componenet of the patch? Non-ARMv7M targets
also benefit from your bare-metal/dependency work. I found the patch
difficult to read with the two matters mixed.
> 1. A new configure option --enable-newlib-arm-v7m. When this option
> is in effect, crt0.S does not make use of RDI to get the stack
> pointer, or make any other RDI calls during startup. That
> eliminates access to the command-line, etc., but it also makes it
> possible to use crt0.o without semihosting support.
Rather than a configure option, I'd prefer to see the bare-metal
support implemented as a libgloss/arm target, joining the ranks of
RDI, RDP, and RedBoot.
> 3. Avoids calling initialise_monitor_handlers from _start. That
> avoids pulling in all of syscalls.c into every program, and, since
> syscalls.c depends on RDI, avoids pulling in RDI support. Instead,
> For reasons I don't understand, initialise_monitor_handles setup
> stdio. I don't see why that is required, and removing that avoids
> pulling in stdio for a program using _open.
> 4. Factors _exit out into a separate file. Every program needs _exit,
> but not every program needs _open, etc. We could further factor
I'm a big fan of avoid unnecessary dependencies.
> If this is approved, I'll commit it to libgloss too, unless explicitly
> told not to do so.
newlib/libc/sys/arm/ is out of sync with libgloss/arm/. You might have
a little trouble applying your patch. I'd like to see libc/sys/arm
permanently removed and --disable-newlib-supplied-syscalls become the
default. Is this possible, Jeff?