/* * petvia.c - VIA emulation in the PET. * * Written by * Andre Fachat * Andreas Boose * Marco van den Heuvel * * This file is part of VICE, the Versatile Commodore Emulator. * See README for copyright notice. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA * 02111-1307 USA. * */ #include "vice.h" #include #include "crtc.h" #include "datasette.h" #include "drive.h" #include "interrupt.h" #include "joystick.h" #include "keyboard.h" #include "lib.h" #include "log.h" #include "maincpu.h" #include "parallel.h" #include "pet.h" #include "petsound.h" #include "petvia.h" #include "tapeport.h" #include "types.h" #include "userport.h" #include "via.h" void via_store(uint16_t addr, uint8_t data) { viacore_store(machine_context.via, addr, data); } uint8_t via_read(uint16_t addr) { return viacore_read(machine_context.via, addr); } uint8_t via_peek(uint16_t addr) { return viacore_peek(machine_context.via, addr); } /* switching PET charrom with CA2 */ static void set_ca2(via_context_t *via_context, int state) { crtc_set_chargen_offset(state ? 256 : 0); } /* switching userport strobe with CB2 */ static void set_cb2(via_context_t *via_context, int state, int offset) { store_userport_pa2((uint8_t)state); petsound_store_manual(state, *via_context->clk_ptr - offset); } static void set_int(via_context_t *via_context, unsigned int int_num, int value, CLOCK rclk) { interrupt_set_irq(maincpu_int_status, int_num, value, rclk); } static void restore_int(via_context_t *via_context, unsigned int int_num, int value) { interrupt_restore_irq(maincpu_int_status, int_num, value); } static void undump_pra(via_context_t *via_context, uint8_t byte) { store_userport_pbx(byte, USERPORT_NO_PULSE); } static void store_pra(via_context_t *via_context, uint8_t byte, uint8_t myoldpa, uint16_t addr) { store_userport_pbx(byte, USERPORT_NO_PULSE); } static void undump_prb(via_context_t *via_context, uint8_t byte) { parallel_cpu_set_nrfd((uint8_t)(!(byte & 0x02))); parallel_cpu_restore_atn((uint8_t)(!(byte & 0x04))); } static void store_prb(via_context_t *via_context, uint8_t byte, uint8_t myoldpb, uint16_t addr) { if ((addr == VIA_DDRB) && (via_context->via[addr] & 0x20)) { log_warning(via_context->log, "PET: Killer POKE! might kill a real PET!\n"); } parallel_cpu_set_nrfd((uint8_t)(!(byte & 0x02))); parallel_cpu_set_atn((uint8_t)(!(byte & 0x04))); if ((byte ^ myoldpb) & 0x8) { tapeport_toggle_write_bit(TAPEPORT_PORT_1, (~(via_context->via[VIA_DDRB]) | byte) & 0x8); tapeport_toggle_write_bit(TAPEPORT_PORT_2, (~(via_context->via[VIA_DDRB]) | byte) & 0x8); } tapeport_set_motor(TAPEPORT_PORT_2, ((~(via_context->via[VIA_DDRB]) | byte) & 0x10) ? 0 : 1); } static void undump_pcr(via_context_t *via_context, uint8_t byte) { #if 0 register uint8_t tmp = byte; /* first set bit 1 and 5 to the real output values */ if ((tmp & 0x0c) != 0x0c) { tmp |= 0x02; } if ((tmp & 0xc0) != 0xc0) { tmp |= 0x20; } crtc_set_char(byte & 2); /* switching PET charrom with CA2 */ /* switching userport strobe with CB2 */ #endif petsound_store_manual((byte & 0xe0) == 0xe0, *via_context->clk_ptr); /* Manual control of CB2 sound */ } static uint8_t store_pcr(via_context_t *via_context, uint8_t byte, uint16_t addr) { #if 0 if (byte != via_context->via[VIA_PCR]) { register uint8_t tmp = byte; /* first set bit 1 and 5 to the real output values */ if ((tmp & 0x0c) != 0x0c) { tmp |= 0x02; } if ((tmp & 0xc0) != 0xc0) { tmp |= 0x20; } crtc_set_char(byte & 2); /* switching PET charrom with CA2 */ /* switching userport strobe with CB2 */ store_userport_pa2((byte & 0x20) >> 5); } #endif return byte; } static inline bool IS_SR_SHIFT_OUT_BY_T2(uint8_t acr) { return (((acr) & VIA_ACR_SR_CONTROL) == VIA_ACR_SR_OUT_FREE_T2 || ((acr) & VIA_ACR_SR_CONTROL) == VIA_ACR_SR_OUT_T2); } /* * Cut out extremely high frequencies that are not properly * suppressed by the low-pass filter, by requiring a minimum * value for T2L of 0. * TODO: make the low-pass filter more effective. */ static inline bool SOUND_ACTIVE(uint8_t acr, uint8_t t2ll) { return !IS_SR_SHIFT_OUT_BY_T2(acr) || t2ll; } /* * Help the sound to avoid background noise. */ static void undump_acr(via_context_t *via_context, uint8_t byte) { petsound_store_onoff(SOUND_ACTIVE(byte, via_context->via[VIA_T2LL])); } static void store_acr(via_context_t *via_context, uint8_t byte) { petsound_store_onoff(SOUND_ACTIVE(byte, via_context->via[VIA_T2LL])); } static void store_sr(via_context_t *via_context, uint8_t byte) { } static void store_t2l(via_context_t *via_context, uint8_t byte) { petsound_store_onoff(SOUND_ACTIVE(via_context->via[VIA_ACR], byte)); } static void reset(via_context_t *via_context) { /* set IEC output lines */ parallel_cpu_set_atn(0); parallel_cpu_set_nrfd(0); store_userport_pbx(0xff, USERPORT_NO_PULSE); store_userport_pa2(1); } inline static uint8_t read_pra(via_context_t *via_context, uint16_t addr) { uint8_t byte = 0xff; byte = read_userport_pbx(byte); /* joystick always pulls low, even if high output, so no masking with DDRA */ /*return ((j & ~(via_context->via[VIA_DDRA])) | (via_context->via[VIA_PRA] & via_context->via[VIA_DDRA]));*/ return byte; } static uint8_t read_prb(via_context_t *via_context) { uint8_t byte; drive_cpu_execute_all(maincpu_clk); /* read parallel IEC interface line states */ byte = 255 - (parallel_nrfd ? 64 : 0) - (parallel_ndac ? 1 : 0) - (parallel_dav ? 128 : 0); /* vertical retrace */ byte -= crtc_offscreen() ? 32 : 0; /* none of the load changes output register value -> std. masking */ byte = ((byte & ~(via_context->via[VIA_DDRB])) | (via_context->via[VIA_PRB] & via_context->via[VIA_DDRB])); return byte; } void via_init(via_context_t *via_context) { viacore_init(machine_context.via, maincpu_alarm_context, maincpu_int_status); } void petvia_setup_context(machine_context_t *machinecontext) { via_context_t *via; machinecontext->via = lib_malloc(sizeof(via_context_t)); via = machinecontext->via; via->prv = NULL; via->context = NULL; via->rmw_flag = &maincpu_rmw_flag; via->clk_ptr = &maincpu_clk; via->myname = lib_msprintf("Via"); via->my_module_name = lib_msprintf("VIA"); viacore_setup_context(via); via->irq_line = IK_IRQ; via->undump_pra = undump_pra; via->undump_prb = undump_prb; via->undump_pcr = undump_pcr; via->undump_acr = undump_acr; via->store_pra = store_pra; via->store_prb = store_prb; via->store_pcr = store_pcr; via->store_acr = store_acr; via->store_sr = store_sr; via->store_t2l = store_t2l; via->read_pra = read_pra; via->read_prb = read_prb; via->set_int = set_int; via->restore_int = restore_int; via->set_ca2 = set_ca2; via->set_cb2 = set_cb2; via->reset = reset; }