fabs              395 src/dps8/dps8_math.c 
fabs              540 src/simh/sim_timer.c                  sim_fmt_secs (fabs(rtc_clock_skew_max[tmr])),
fabs              680 src/simh/sim_timer.c         if (fabs(skew) > fabs(rtc_clock_skew_max[tmr]))