1 /* 2 * PROJECT: NEC PC-98 series onboard hardware 3 * LICENSE: GPL-2.0-or-later (https://spdx.org/licenses/GPL-2.0-or-later) 4 * PURPOSE: CPU I/O ports header file 5 * COPYRIGHT: Copyright 2020 Dmitry Borisov (di.sean@protonmail.com) 6 */ 7 8 #pragma once 9 10 #define CPU_IO_o_RESET 0xF0 11 #define CPU_IO_o_A20_UNMASK 0xF2 12 13 #define CPU_IO_o_A20_CONTROL 0xF6 14 #define CPU_A20_ENABLE 0x02 15 #define CPU_A20_DISABLE 0x03 16 17 #define CPU_IO_o_FPU_BUSY_LATCH 0xF8 18 19 /* 20 * ARTIC (A Relative Time Indication Counter) - 24-bit binary up counter 21 */ 22 #define CPU_IO_o_ARTIC_DELAY 0x5F /* Constant delay (about 600 ns) */ 23 #define CPU_IO_i_ARTIC_0 0x5C 24 #define CPU_IO_i_ARTIC_1 0x5D 25 #define CPU_IO_i_ARTIC_2 0x5E 26 #define CPU_IO_i_ARTIC_3 0x5F 27 28 #define ARTIC_FREQUENCY 307200 29 #define ARTIC_FREQUENCY_0_1 ARTIC_FREQUENCY 30 #define ARTIC_FREQUENCY_2_3 (ARTIC_FREQUENCY >> 8) 31