commit 242a27cc3b3033898b4ead86d16dfef765cfe5b4
author Ewout van Bekkum <ewout@google.com> Mon Dec 20 08:59:35 2021 -0800
committer CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com> Mon Jan 10 18:19:04 2022 +0000
tree 2fe4df742fa5c75a34d55114bdd30c17d21a3348
parent d56a6386ca2422ce7ee50f0e917e5b2b6e100257

pw_preprocessor: Add internal Cortex-M arch defines

Instead of forking build rules to be arch specific, which does not
scale well with the number of CortexM arches, use a common place to
determine the arch macros which can be used by other macros.

Note that these defines are private and internal to Pigweed and
should not be used by downstream projects, they are expected to
be moved and renamed in the near future.

The defines default to the format used by CMSIS, GCC, Clang, etc.
but they follow a module compile time configuration paradigm so
different toolchains can also make the following defines work:
- _PW_ARCH_ARM_V6M
- _PW_ARCH_ARM_V7M
- _PW_ARCH_ARM_V7EM
- _PW_ARCH_ARM_V8M_BASELINE
- _PW_ARCH_ARM_V8M_MAINLINE
- _PW_ARCH_ARM_V8_1M_MAINLINE

Lastly a helper is provided if any of the above have a value of 1:
- _PW_ARCH_ARM_CORTEX_M

Also updates pw_boot_cortex_m, pw_cpu_exception_cortex_m, and
pw_interrupt_cortex_m to use this source of architecture selection
deprecating the previously independent build targets.

Change-Id: Ie0ed3fb976ea3520c4f7f84debf3d598cf5ca559
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/75540
Pigweed-Auto-Submit: Ewout van Bekkum <ewout@google.com>
Reviewed-by: Keir Mierle <keir@google.com>
Commit-Queue: Auto-Submit <auto-submit@pigweed.google.com.iam.gserviceaccount.com>