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- /*
- * SMS emulation
- * (C) notaz, 2009-2010
- *
- * This work is licensed under the terms of MAME license.
- * See COPYING file in the top-level directory.
- */
- /*
- * TODO:
- * - start in a state as if BIOS ran
- * - remaining status flags (OVR/COL)
- * - RAM support in mapper
- * - region support
- * - Pause button (NMI)
- * - SN76496 DAC-like usage
- * - H counter
- */
- #include "pico_int.h"
- #include "memory.h"
- #include "sound/sn76496.h"
- static unsigned char vdp_data_read(void)
- {
- struct PicoVideo *pv = &Pico.video;
- unsigned char d;
- d = Pico.vramb[pv->addr];
- pv->addr = (pv->addr + 1) & 0x3fff;
- pv->pending = 0;
- return d;
- }
- static unsigned char vdp_ctl_read(void)
- {
- unsigned char d = Pico.video.pending_ints << 7;
- Pico.video.pending = 0;
- Pico.video.pending_ints = 0;
- elprintf(EL_SR, "VDP sr: %02x", d);
- return d;
- }
- static void vdp_data_write(unsigned char d)
- {
- struct PicoVideo *pv = &Pico.video;
- if (pv->type == 3) {
- Pico.cram[pv->addr & 0x1f] = d;
- Pico.m.dirtyPal = 1;
- } else {
- Pico.vramb[pv->addr] = d;
- }
- pv->addr = (pv->addr + 1) & 0x3fff;
- pv->pending = 0;
- }
- static void vdp_ctl_write(unsigned char d)
- {
- struct PicoVideo *pv = &Pico.video;
- if (pv->pending) {
- if ((d >> 6) == 2) {
- pv->reg[d & 0x0f] = pv->addr;
- elprintf(EL_IO, " VDP r%02x=%02x", d & 0x0f, pv->addr & 0xff);
- }
- pv->type = d >> 6;
- pv->addr &= 0x00ff;
- pv->addr |= (d & 0x3f) << 8;
- } else {
- pv->addr &= 0x3f00;
- pv->addr |= d;
- }
- pv->pending ^= 1;
- }
- static unsigned char z80_sms_in(unsigned short a)
- {
- unsigned char d = 0;
- elprintf(EL_IO, "z80 port %04x read", a);
- a &= 0xc1;
- switch (a)
- {
- case 0x00:
- case 0x01:
- d = 0xff;
- break;
- case 0x40: /* V counter */
- d = Pico.video.v_counter;
- elprintf(EL_HVCNT, "V counter read: %02x", d);
- break;
- case 0x41: /* H counter */
- d = Pico.m.rotate++;
- elprintf(EL_HVCNT, "H counter read: %02x", d);
- break;
- case 0x80:
- d = vdp_data_read();
- break;
- case 0x81:
- d = vdp_ctl_read();
- break;
- case 0xc0: /* I/O port A and B */
- d = ~((PicoPad[0] & 0x3f) | (PicoPad[1] << 6));
- break;
- case 0xc1: /* I/O port B and miscellaneous */
- d = (Pico.ms.io_ctl & 0x80) | ((Pico.ms.io_ctl << 1) & 0x40) | 0x30;
- d |= ~(PicoPad[1] >> 2) & 0x0f;
- break;
- }
- elprintf(EL_IO, "ret = %02x", d);
- return d;
- }
- static void z80_sms_out(unsigned short a, unsigned char d)
- {
- elprintf(EL_IO, "z80 port %04x write %02x", a, d);
- a &= 0xc1;
- switch (a)
- {
- case 0x01:
- Pico.ms.io_ctl = d;
- break;
- case 0x40:
- case 0x41:
- if (PicoOpt & POPT_EN_PSG)
- SN76496Write(d);
- break;
- case 0x80:
- vdp_data_write(d);
- break;
- case 0x81:
- vdp_ctl_write(d);
- break;
- }
- }
- static int bank_mask;
- static void write_bank(unsigned short a, unsigned char d)
- {
- elprintf(EL_Z80BNK, "bank %04x %02x @ %04x", a, d, z80_pc());
- switch (a & 0x0f)
- {
- case 0x0c:
- elprintf(EL_STATUS|EL_ANOMALY, "%02x written to control reg!", d);
- break;
- case 0x0d:
- if (d != 0)
- elprintf(EL_STATUS|EL_ANOMALY, "bank0 changed to %d!", d);
- break;
- case 0x0e:
- d &= bank_mask;
- z80_map_set(z80_read_map, 0x4000, 0x7fff, Pico.rom + (d << 14), 0);
- #ifdef _USE_CZ80
- Cz80_Set_Fetch(&CZ80, 0x4000, 0x7fff, (FPTR)Pico.rom + (d << 14));
- #endif
- break;
- case 0x0f:
- d &= bank_mask;
- z80_map_set(z80_read_map, 0x8000, 0xbfff, Pico.rom + (d << 14), 0);
- #ifdef _USE_CZ80
- Cz80_Set_Fetch(&CZ80, 0x8000, 0xbfff, (FPTR)Pico.rom + (d << 14));
- #endif
- break;
- }
- Pico.ms.carthw[a & 0x0f] = d;
- }
- static void xwrite(unsigned int a, unsigned char d)
- {
- elprintf(EL_IO, "z80 write [%04x] %02x", a, d);
- if (a >= 0xc000)
- Pico.zram[a & 0x1fff] = d;
- if (a >= 0xfff8)
- write_bank(a, d);
- }
- void PicoResetMS(void)
- {
- z80_reset();
- PsndReset(); // pal must be known here
- }
- void PicoPowerMS(void)
- {
- int s, tmp;
- memset(&Pico.ram,0,(unsigned char *)&Pico.rom - Pico.ram);
- memset(&Pico.video,0,sizeof(Pico.video));
- memset(&Pico.m,0,sizeof(Pico.m));
- Pico.m.pal = 0;
- // calculate a mask for bank writes.
- // ROM loader has aligned the size for us, so this is safe.
- s = 0; tmp = Pico.romsize;
- while ((tmp >>= 1) != 0)
- s++;
- if (Pico.romsize > (1 << s))
- s++;
- tmp = 1 << s;
- bank_mask = (tmp - 1) >> 14;
- Pico.ms.carthw[0x0e] = 1;
- Pico.ms.carthw[0x0f] = 2;
- PicoReset();
- }
- void PicoMemSetupMS(void)
- {
- z80_map_set(z80_read_map, 0x0000, 0xbfff, Pico.rom, 0);
- z80_map_set(z80_read_map, 0xc000, 0xdfff, Pico.zram, 0);
- z80_map_set(z80_read_map, 0xe000, 0xffff, Pico.zram, 0);
- z80_map_set(z80_write_map, 0x0000, 0xbfff, xwrite, 1);
- z80_map_set(z80_write_map, 0xc000, 0xdfff, Pico.zram, 0);
- z80_map_set(z80_write_map, 0xe000, 0xffff, xwrite, 1);
-
- #ifdef _USE_DRZ80
- drZ80.z80_in = z80_sms_in;
- drZ80.z80_out = z80_sms_out;
- #endif
- #ifdef _USE_CZ80
- Cz80_Set_Fetch(&CZ80, 0x0000, 0xbfff, (FPTR)Pico.rom);
- Cz80_Set_Fetch(&CZ80, 0xc000, 0xdfff, (FPTR)Pico.zram);
- Cz80_Set_Fetch(&CZ80, 0xe000, 0xffff, (FPTR)Pico.zram);
- Cz80_Set_INPort(&CZ80, z80_sms_in);
- Cz80_Set_OUTPort(&CZ80, z80_sms_out);
- #endif
- }
- void PicoStateLoadedMS(void)
- {
- write_bank(0xfffe, Pico.ms.carthw[0x0e]);
- write_bank(0xffff, Pico.ms.carthw[0x0f]);
- }
- void PicoFrameMS(void)
- {
- struct PicoVideo *pv = &Pico.video;
- int is_pal = Pico.m.pal;
- int lines = is_pal ? 313 : 262;
- int cycles_line = is_pal ? 58020 : 58293; /* (226.6 : 227.7) * 256 */
- int cycles_done = 0, cycles_aim = 0;
- int skip = PicoSkipFrame;
- int lines_vis = 192;
- int hint; // Hint counter
- int y;
- PicoFrameStartMode4();
- hint = pv->reg[0x0a];
- for (y = 0; y < lines; y++)
- {
- pv->v_counter = Pico.m.scanline = y;
- if (y > 218)
- pv->v_counter = y - 6;
- if (y < lines_vis && !skip)
- PicoLineMode4(y);
- if (y <= lines_vis)
- {
- if (--hint < 0)
- {
- hint = pv->reg[0x0a];
- pv->pending_ints |= 2;
- if (pv->reg[0] & 0x10) {
- elprintf(EL_INTS, "hint");
- z80_int();
- }
- }
- }
- else if (y == lines_vis + 1) {
- pv->pending_ints |= 1;
- if (pv->reg[1] & 0x20) {
- elprintf(EL_INTS, "vint");
- z80_int();
- }
- }
- cycles_aim += cycles_line;
- cycles_done += z80_run((cycles_aim - cycles_done) >> 8) << 8;
- }
- if (PsndOut)
- PsndGetSamplesMS();
- }
- void PicoFrameDrawOnlyMS(void)
- {
- int lines_vis = 192;
- int y;
- PicoFrameStartMode4();
- for (y = 0; y < lines_vis; y++)
- PicoLineMode4(y);
- }
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