- the pointers must be flagged as volatile because otherwise they
might be "optimized" by a compiler. It is a common good
practice to access the registers this way, the keyword is in C
for a reason.
- for instance, in eeprom_eerd() when polling a register the
compiler, under certain conditions, may decide upon the first
read and if it does not break the loop it assumes that the
value is not going to change and thus stays in an infinite
loop.
assert(reg < 0x1ffff);
/* Read from memory mapped register. */
- value = *(u32_t *)(e->regs + reg);
+ value = *(volatile u32_t *)(e->regs + reg);
/* Return the result. */
return value;
assert(reg < 0x1ffff);
/* Write to memory mapped register. */
- *(u32_t *)(e->regs + reg) = value;
+ *(volatile u32_t *)(e->regs + reg) = value;
}
/*===========================================================================*