set_SCU_clock    2010 src/dps8/dps8_scu.c               (int64) (new_clk - set_SCU_clock (cpup, scu_unit_idx));
set_SCU_clock    2277 src/dps8/dps8_scu.c             uint64 clk = set_SCU_clock (cpup, scu_unit_idx) & ((1llu << 52) - 1); // 52 bits