From: "R. Diez" <rdiezmail-newlib@yahoo.de>
To: Keith Packard <keithp@keithp.com>
Cc: Jeff Johnston <jjohnstn@redhat.com>,
"newlib@sourceware.org" <newlib@sourceware.org>
Subject: Re: _REENT_CHECK_VERIFY calls __assert_func even if NDEBUG is defined
Date: Wed, 29 Apr 2020 15:05:02 +0200 [thread overview]
Message-ID: <83127821-8a4f-b4a4-3fc2-3dcd5e6110ed@yahoo.de> (raw)
In-Reply-To: <878sifp8y8.fsf@keithp.com>
> If you're tight on RAM, you might look at the newlib fork, picolibc,
> which uses native TLS support for reentrant data values like
> _rand_next. With that approach, your thread-local storage contains only
> values used by your application and malloc need never be called. In this
> case, the per-thread data would be only eight bytes.
I do have one microcontroller with 8 KiB SRAM. For all others I do not want to bother.
I am interested in your "only eight bytes" claim. Say I use picolibc, and then my firmware wants to use rand(), which needs many more bytes for the
state of the pseudo-random number generator.
The firmware is bare metal (no operating system). I guess there will not be a native TLS support then.
How does rand() get the memory it needs? Do I need to preallocate it statically? Or have a separate memory pool for the TLS? Do I need to implement
TLS myself? Can you do that with some sort of easy-to-code stack?
Regards,
rdiez
prev parent reply other threads:[~2020-04-29 13:05 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <989180140.2023825.1588003097077.ref@mail.yahoo.com>
2020-04-27 15:58 ` R. Diez
2020-04-27 17:39 ` Jeff Johnston
2020-04-27 20:29 ` R. Diez
2020-04-27 23:57 ` Jeff Johnston
2020-04-28 12:06 ` R. Diez
2020-04-29 19:51 ` Jeff Johnston
2020-04-30 8:08 ` R. Diez
2020-04-28 19:36 ` FAQ link to crossgcc broken R. Diez
2020-04-28 19:57 ` _REENT_CHECK_VERIFY calls __assert_func even if NDEBUG is defined R. Diez
2020-04-28 22:00 ` Keith Packard
2020-04-29 13:05 ` R. Diez [this message]
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