- switch (cmd)
- {
- case 0:
- case 0x4d5f: // 'M_' from BIOS
- spin(64);
- continue;
- case CMD_ECHO:
- v = read16(&r[0x22/2]) ^ (is_slave << 15);
- write16(&r[0x24/2], v);
- break;
- case CMD_READ_FRT:
- v = read_frt();
- write16(&r[0x24/2], v);
- break;
- }