CMSIS repo does not support pre-processor defines, hence multiple assembly
files are added for secure/non-secure and floating point tools.
Mbed OS tools support assembly file pre-processing, but the build system
does not support multiple assembly files for each target, hence updating
the assembly files.
1. Patch RTX so irq_cm4f.S files work with no FPU targets
2. Patch RTX so irq_armv8mml.S files to work with and without FPU
2. Patch RTX so irq_armv8mml.S and irq_armv8mbl.S files to work with secure and
non-secure builds
1. Revert "CMSIS/RTX: __FPU_USED to be set based on HW FPU support"
This reverts commit b4f5bed7e75c21927c954a50d40422b81a1de5a0.
2. Revert "CMSIS/RTX: Update Armv8M IAR 8.x assembly files - add END"
This reverts commit b228cd9db0.
3. Revert "CMSIS/RTX: Pre-processor defines used for assembly"
This reverts commit 287121ffdc.
4. Revert "CMSIS/RTX: Patch RTX so irq_cm4f.s files work with no FPU targets"
This reverts commit cc2e0517e1.
Use a busy loop with non-blocking Semaphore::wait(0) calls instead of a
single Semaphore::wait(osWaitForever) to improve time measurement
accuracy. Looping in Semaphore::wait(0) prevents the board from entering
sleep or deepsleep modes while waiting for the semaphore. By skipping
the overhead wakeup time, we get more accurate timings.
Add atomic load and store functions, and add barriers to the existing atomic
functions.
File currently has no explicit barriers - we don't support SMP, so don't
need CPU barriers.
But we do need to worry about compiler barriers - particularly if link time
optimisation is activated so that the compiler can see inside these
functions. The assembler or intrinsics that access PRIMASK for
enter/exit critical act as barriers, but LDREX, STREX and simple
volatile pointer loads and stores do not.