ns_to_cycles
if ((ns_to_cycles(sdram->tck, sd_khz) > 1) ||
twr = ns_to_cycles(sdram->twr, mem_khz);
trp = ns_to_cycles(sdram->trp, mem_khz) - 1;
ns_to_cycles(sdram->trcd, mem_khz));
u_int dri = ns_to_cycles(ns_row, cpu_khz / 2) / 32;