irq_arch.h previously included cpu.h, which in term included the vendor header
files. Those were needed to get the GIE define (general interrupt enable bit).
However, the vendor files use fancy defines like `#define N (0x0004)` that
easily conflict with application code. Due to the widespread use of the IRQ API,
it is better to not include the vendor files in irq_arch.h.
This commit adds a local define for the GIE bit and uses this instead of
including cpu.h.
Both tests/pthread_tls and tests/prng_sha256prng fail without this, but
other platforms run fine with their defaults. Lets consider the higher
value a better default.
- Updated to inline-able IRQ API
- Improved robustness of functions
- Added memory barrier to prevent the compiler from moving code outside of
a critical section guarded by irq_disable() ... irq_restore()
- Reduced overhead of `irq_disable()`
- After clearing the global interrupt enable (GIE) bit, IRQs remain enabled
for up to one CPU cycle
- The previous implementation just added a nop to fill that cycle
- This implementation uses the cycle for masking the return value
- Reduced overhead of `irq_restore()`
- Now only one CPU cycle is needed
- `irq_disable()`, `irq_restore()`, and `irq_enable()` work now in constant time
- TI documentation for msp430f1xx is ambiguous regarding length
of some memmory sectors. For some cpu's the acual size is 1/4 byte
smaller than advertised and one of the sectors is actually 256b and
not 512.
ref: https://e2e.ti.com/support/microcontrollers/msp430/f/166/p/798838/2962979#2962979
- Remove the first 256b sector from usage since there is not support for
variable sized pages
- Fix msp430f2617 FLASHPAGE_NUMOFF to represent accesible memory
