>However, RRF or RLF STATUS,F will not work conventionally. Regardless of >any input conditions, the Z and DC bits will never change. The C bit >will either be copied from bit 7 on a rotate left or copied from bit 0 >(which is the old C bit) on a rotate right. The TO and PD bits will of >course not change. Good question, Dmitry. Continuing on from Mike Keitz's comments. The RLF, RRF instructions only affect the C bit in STATUS, and since TO and PD are READ only, I agree they will be unchanged, so the result will be to rotate all the other STATUS reg bits, either way. But with the TO and PD bits being unchanged. Since RLF RRF update C, presumably AFTER the rotate. So... BEFORE: IRP RP1 RP0 TO PD Z DC C AFTER: RLF STATUS,F RP1 RP0 TO TO PD DC Z IRP And.. BEFORE: IRP RP1 RP0 TO PD Z DC C AFTER: RRF STATUS,F C IRP RP1 TO PD PD Z C Can anyone confirm that this actually happens?...If so are there any clever uses for such a trick. (copying DC into Z etc.) Ray Gardiner Technical Director DSP Systems ray@dsp-systems.com private email to:- ray@netspace.net.au http://www.dsp-systems.com