MC_REGA
mc146818_write(sc, MC_REGA, MC_BASE_32_KHz | MC_RATE_1024_Hz);
mc146818_write(NULL, MC_REGA, MC_BASE_32_KHz | MC_RATE_128_Hz);
mc146818_write(NULL, MC_REGA,
mc146818_write(NULL, MC_REGA,
mc146818_write(NULL, MC_REGA, MC_BASE_32_KHz | MC_RATE_128_Hz);
mc146818_write(NULL, MC_REGA,
mc146818_write(NULL, MC_REGA,
mc146818_write(sc, MC_REGA, MC_BASE_32_KHz | MC_RATE_NONE);
while (mc146818_read(sc, MC_REGA) & MC_REGA_UIP) \
period = rtc.regs[MC_REGA] & MC_RATE_MASK;
rtc.regs[MC_REGA] = data;
if ((rtc.regs[MC_REGA] ^ data) & 0x0f)
case MC_REGA: