*/
/*
* TODO:
- * - start in a state as if BIOS ran
- * - region support
+ * - start in a state as if BIOS ran (partly done for VDP registers, RAM)
+ * - region support (currently only very limited PAL and Mark-III support)
+ * - mappers: EEPROM, some obscure Korean (Nemesis, Janggun)
*/
#include "pico_int.h"
#include "memory.h"
pv->pending ^= 1;
}
+static u8 vdp_hcounter(int cycles)
+{
+ // 171 slots per scanline of 228 clocks, counted 0xf4-0x93, 0xe9-0xf3
+ // this matches h counter tables in SMSVDPTest:
+ // hc = (cycles+2) * 171 /228 -1 + 0xf4;
+ int hc = (((cycles+2) * ((171<<8)/228))>>8)-1 + 0xf4; // Q8 to avoid dividing
+ if (hc > 0x193) hc += 0xe9-0x93-1;
+ return hc;
+}
+
static unsigned char z80_sms_in(unsigned short a)
{
unsigned char d = 0xff;
Pico.ms.io_gg[a] = d;
} else {
// pad. latch hcounter if one of the TH lines is switched to 1
- if ((Pico.ms.io_ctl ^ d) & d & 0xa0) {
- unsigned c = 228-z80_cyclesLeft;
- // 171 slots per scanline of 228 clocks, counted 0xf4-0x93,0xe9-0xf3
- // this matches h counter tables in SMSVDPTest
- c = (((c+2) * ((171<<8)/228))>>8)-1 + 0xf4; // Q8 to avoid dividing
- if (c > 0x193) c += 0xe9-0x93-1;
- Pico.ms.vdp_hlatch = (u8)c;
- }
+ if ((Pico.ms.io_ctl ^ d) & d & 0xa0)
+ Pico.ms.vdp_hlatch = vdp_hcounter(228 - z80_cyclesLeft);
Pico.ms.io_ctl = d;
}
break;
// 16KB bank mapping for Sega mapper
static void write_bank_sega(unsigned short a, unsigned char d)
{
- if (Pico.ms.mapper != 1 && (Pico.ms.mapper || d == 0)) return;
+ // avoid mapper detection for RAM fill with 0
+ if (Pico.ms.mapper != PMS_MAP_SEGA && (Pico.ms.mapper || d == 0)) return;
elprintf(EL_Z80BNK, "bank 16k %04x %02x @ %04x", a, d, z80_pc());
- Pico.ms.mapper = 1;
+ Pico.ms.mapper = PMS_MAP_SEGA;
Pico.ms.carthw[a & 0x0f] = d;
switch (a & 0x0f)
}
}
-// 8KB ROM mapping for MSX mapper
+// 16KB bank mapping for Codemasters mapper, TODO: SRAM support
+static void write_bank_codem(unsigned short a, unsigned char d)
+{
+ // don't detect @0x0 to avoid confusing with MSX
+ if (Pico.ms.mapper != PMS_MAP_CODEM && (Pico.ms.mapper || (a|d) == 0)) return;
+ elprintf(EL_Z80BNK, "bank 16k %04x %02x @ %04x", a, d, z80_pc());
+ Pico.ms.mapper = PMS_MAP_CODEM;
+ Pico.ms.carthw[a>>14] = d;
+
+ d &= bank_mask;
+ z80_map_set(z80_read_map, a, a+0x3fff, Pico.rom + (d << 14), 0);
+}
+
+// 8KB bank mapping for MSX mapper
static void write_bank_msx(unsigned short a, unsigned char d)
{
- if (Pico.ms.mapper != 2 && (Pico.ms.mapper || (a|d) == 0)) return;
+ // don't detect @0x0 to avoid confusing with Codemasters
+ if (Pico.ms.mapper != PMS_MAP_MSX && (Pico.ms.mapper || (a|d) == 0)) return;
elprintf(EL_Z80BNK, "bank 8k %04x %02x @ %04x", a, d, z80_pc());
- Pico.ms.mapper = 2; // TODO define (more) mapper types
+ Pico.ms.mapper = PMS_MAP_MSX;
Pico.ms.carthw[a] = d;
a = (a^2)*0x2000 + 0x4000;
z80_map_set(z80_read_map, a, a+0x1fff, Pico.rom + (d << 13), 0);
}
-static void write_bank_32k(unsigned short a, unsigned char d)
+// 32KB bank mapping for Korean n-in-1 packs
+static void write_bank_n32k(unsigned short a, unsigned char d)
{
- if (Pico.ms.mapper != 3 && (Pico.ms.mapper || z80_pc() < 0xc000)) return;
+ // code must be in RAM since all visible ROM space is swapped
+ if (Pico.ms.mapper != PMS_MAP_N32K && (Pico.ms.mapper || z80_pc() < 0xc000)) return;
elprintf(EL_Z80BNK, "bank 32k %04x %02x @ %04x", a, d, z80_pc());
- Pico.ms.mapper = 3; // TODO define (more) mapper types
+ Pico.ms.mapper = PMS_MAP_N32K;
Pico.ms.carthw[0xf] = d;
d &= bank_mask >> 1;
- z80_map_set(z80_read_map, 0, 0x7fff, Pico.rom + (d << 15), 0);
+ z80_map_set(z80_read_map, 0, 0x7fff, Pico.rom + (d << 15), 0);
+}
+
+// 16KB bank mapping for Korean n-in-1 packs
+static void write_bank_n16k(unsigned short a, unsigned char d)
+{
+ // code must be in RAM since all visible ROM space is swapped
+ if (Pico.ms.mapper != PMS_MAP_N16K && (Pico.ms.mapper || z80_pc() < 0xc000)) return;
+ elprintf(EL_Z80BNK, "bank 16k %04x %02x @ %04x", a, d, z80_pc());
+ Pico.ms.mapper = PMS_MAP_N16K;
+ Pico.ms.carthw[a>>14] = d;
+
+ d &= bank_mask;
+ a = a & 0xc000;
+ // the top bank shifts with the bottom bank.
+ if (a == 0x8000) d += Pico.ms.carthw[0] & 0x30;
+ z80_map_set(z80_read_map, a, a+0x3fff, Pico.rom + (d << 14), 0);
}
-// TODO mapping is currently auto-selecting, but that's not very reliable.
+// TODO mapping is currently auto-selecting, but that's not totally reliable.
+// Before adding more mappers this should be revised.
static void xwrite(unsigned int a, unsigned char d)
{
elprintf(EL_IO, "z80 write [%04x] %02x", a, d);
if (a >= 0xc000)
PicoMem.zram[a & 0x1fff] = d;
- // korean 32k. 1 selectable 32KB bank at the bottom
+ // NB the sequence of mappers is crucial for the auto detection
+ // Korean n-in-1. 1 selectable 32KB bank at the bottom
if (a == 0xffff)
- write_bank_32k(a, d);
- // Sega. Maps 4 bank 16KB each
+ write_bank_n32k(a, d);
+ // Sega. Maps 3 banks 16KB each, SRAM
if (a >= 0xfff8)
write_bank_sega(a, d);
- // Codemasters. Similar to Sega, but different addresses
-// NB mapping on 0x0000 collides with MSX mapper, but AFAICT CM isn't using it
-// if (a == 0x0000)
-// write_bank_sega(0xfffd, d);
- if (a == 0x4000)
- write_bank_sega(0xfffe, d);
- if (a == 0x8000)
- write_bank_sega(0xffff, d);
- // Korean. 1 selectable 16KB bank at the top
- if (a == 0xa000)
- write_bank_sega(0xffff, d);
// MSX. 4 selectable 8KB banks at the top
if (a <= 0x0003)
write_bank_msx(a, d);
+ // Codemasters. Similar to Sega, but different addresses
+ if (a < 0xc000 && (a & 0x3fff) == 0)
+ write_bank_codem(a, d);
+ // Korean. 1 selectable 16KB bank at the top
+ if (a == 0xa000)
+ write_bank_codem(0x8000, d);
+ // Korean n-in-1. 2 selectable 16KB banks, top bank has offset from bottom one
+ if (a == 0x3ffe || a == 0x7fff || a == 0xbfff)
+ write_bank_n16k(a, d);
}
void PicoResetMS(void)
Pico.video.reg[9] = 0x00;
Pico.video.reg[10] = 0xff;
- // BIOS, clean zram
- memset(PicoMem.zram, 0, sizeof(PicoMem.zram));
+ // BIOS, clear zram (fake unitialized on japanese NTSC devices)
+ memset(PicoMem.zram, PicoIn.regionOverride&1 ? 0xf0:0, sizeof(PicoMem.zram));
}
void PicoPowerMS(void)
tmp = 1 << s;
bank_mask = (tmp - 1) >> 14;
+ PicoMem.ioports[0] = 0xc3; // hack to jump @0 at end of RAM to wrap around
Pico.ms.mapper = 0;
PicoReset();
}
Cz80_Set_OUTPort(&CZ80, z80_sms_out);
#endif
- // memory mapper setup
+ // memory mapper setup, linear mapping of 1st 48KB
u8 mapper = Pico.ms.mapper;
- if (Pico.ms.mapper == 2) {
- xwrite(0x0000, 0);
- xwrite(0x0001, 0);
- xwrite(0x0002, 0);
- xwrite(0x0003, 0);
- } else if (Pico.ms.mapper == 3) {
+ if (Pico.ms.mapper == PMS_MAP_MSX) {
+ xwrite(0x0000, 4);
+ xwrite(0x0001, 5);
+ xwrite(0x0002, 2);
+ xwrite(0x0003, 3);
+ } else if (Pico.ms.mapper == PMS_MAP_N32K) {
xwrite(0xffff, 0);
+ } else if (Pico.ms.mapper == PMS_MAP_CODEM) {
+ xwrite(0x0000, 0);
+ xwrite(0x4000, 1);
+ xwrite(0x8000, 2);
} else {
xwrite(0xfffc, 0);
xwrite(0xfffd, 0);
void PicoStateLoadedMS(void)
{
u8 mapper = Pico.ms.mapper;
- if (Pico.ms.mapper == 2) {
+ if (Pico.ms.mapper == PMS_MAP_MSX) {
xwrite(0x0000, Pico.ms.carthw[0]);
xwrite(0x0001, Pico.ms.carthw[1]);
xwrite(0x0002, Pico.ms.carthw[2]);
xwrite(0x0003, Pico.ms.carthw[3]);
- } else if (Pico.ms.mapper == 3) {
+ } else if (Pico.ms.mapper == PMS_MAP_N32K) {
xwrite(0xffff, Pico.ms.carthw[0x0f]);
+ } else if (Pico.ms.mapper == PMS_MAP_CODEM) {
+ xwrite(0x0000, Pico.ms.carthw[0]);
+ xwrite(0x4000, Pico.ms.carthw[1]);
+ xwrite(0x8000, Pico.ms.carthw[2]);
} else {
xwrite(0xfffc, Pico.ms.carthw[0x0c]);
xwrite(0xfffd, Pico.ms.carthw[0x0d]);