2.14.2. The Q flag

You can set the Sticky Overflow, Q flag, to 1 by executing certain multiply and fractional arithmetic instructions:

The Q flag is sticky in that, when set to 1 by an instruction, it remains set until explicitly cleared to 0 by an MSR instruction writing to the CPSR. Instructions cannot execute conditionally on the status of the Q flag.

To determine the status of the Q flag, you must read the PSR into a register and extract the Q flag from this. See the individual instruction definitions in the ARM Architecture Reference Manual for details of how you can set and clear the Q flag.

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