No, a problem with sequence points is at the compiler level, just the same as "volatile". Assume the compiler doesn't reorder anything. Maybe you turn the optim

No, a problem with sequence points is at the compiler level, just the same as "volatile". Assume the compiler doesn't reorder anything. Maybe you turn the optimization off. You even inspect the assembly code, and all the operations are there in the correct order. You can still hit the problem. In my case, the code ran fine until we got an upgraded CPU. (from MPC6xx series to MPC74xx series) Suppose you store to registers at 0xf0000ffc, then 0xf0000104, then 0xf0000ff8. You need the stores to happen in that order. The instructions execute in that order, creating 32-bit chunks of data headed out toward the memory bus. There are multiple write buffers however, so they can go in parallel, each getting a distinct write buffer. They then head out onto the memory bus in some randomish order determined by timing issues internal to the CPU. In my case, I had to add "eieio" instructions between each pair of accesses for which ordering mattered. FYI, that is a real instruction, supposedly meaning "Enforce In-Order Execution of I/O".