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These changes are needed to address bugs that can emerge with the improved optimization from the GCC 10.3 compiler. Updated performance inline functions `mmu_get_uint8()`, ... and `mmu_set_uint8()`, ... to comply with strict-aliasing rules. Without this change, stale data may be referenced. This issue was revealed in discussions on https://github.com/esp8266/Arduino/issues/8261#issue-963529268 Changes to avoid over-optimization of 32-bit wide transfers from IRAM, turning into 8-bit or 16-bit transfers by the new GCC 10.3 compiler. This has been a reoccurring/tricky problem for me with the new compiler. So far referencing the 32-bit value loaded by way of an Extended ASM R/W output register has stopped the compiler from optimizing down to an 8-bit or 16-bit transfer. Example: ```cpp uint32_t val; __builtin_memcpy(&val, v32, sizeof(uint32_t)); asm volatile ("" :"+r"(val)); // inject 32-bit dependency ... ``` Updated example `irammem.ino` * do a simple test of compliance to strict-aliasing rules * For `mmu_get_uint8()`, added tests to evaluate if 32-bit wide transfers were converted to an 8-bit transfer.