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picodrive/pico/videoport.c
notaz cff531af94 clarify PicoDrive's license 
- PicoDrive was originally released by fDave with simple
  "free for non-commercial use / For commercial use, separate licencing
  terms must be obtained" license and I kept it in my releases.
- in 2011, fDave re-released his code (same that I used as base
  many years ago) dual licensed with GPLv2 and MAME licenses:
    https://code.google.com/p/cyclone68000/

Based on the above I now proclaim that the whole source code is licensed
under the MAME license as more elaborate form of "for non-commercial use".
If that raises any doubt, I announce that all my modifications (which
is the vast majority of code by now) is licensed under the MAME license,
as it reads in COPYING file in this commit.

This does not affect ym2612.c/sn76496.c that were MAME licensed already
from the beginning.
2013-06-26 03:07:07 +03:00

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/*
* PicoDrive
* (c) Copyright Dave, 2004
* (C) notaz, 2006-2009
*
* This work is licensed under the terms of MAME license.
* See COPYING file in the top-level directory.
*/
#include "pico_int.h"
#include "cd/gfx_cd.h"
extern const unsigned char hcounts_32[];
extern const unsigned char hcounts_40[];
#ifndef UTYPES_DEFINED
typedef unsigned char u8;
typedef unsigned short u16;
typedef unsigned int u32;
#define UTYPES_DEFINED
#endif
int (*PicoDmaHook)(unsigned int source, int len, unsigned short **srcp, unsigned short **limitp) = NULL;
static __inline void AutoIncrement(void)
{
Pico.video.addr=(unsigned short)(Pico.video.addr+Pico.video.reg[0xf]);
}
static void VideoWrite(u16 d)
{
unsigned int a=Pico.video.addr;
switch (Pico.video.type)
{
case 1: if(a&1) d=(u16)((d<<8)|(d>>8)); // If address is odd, bytes are swapped (which game needs this?)
Pico.vram [(a>>1)&0x7fff]=d;
if (a - ((unsigned)(Pico.video.reg[5]&0x7f) << 9) < 0x400)
rendstatus |= PDRAW_DIRTY_SPRITES;
break;
case 3: Pico.m.dirtyPal = 1;
Pico.cram [(a>>1)&0x003f]=d; break; // wraps (Desert Strike)
case 5: Pico.vsram[(a>>1)&0x003f]=d; break;
//default:elprintf(EL_ANOMALY, "VDP write %04x with bad type %i", d, Pico.video.type); break;
}
AutoIncrement();
}
static unsigned int VideoRead(void)
{
unsigned int a=0,d=0;
a=Pico.video.addr; a>>=1;
switch (Pico.video.type)
{
case 0: d=Pico.vram [a&0x7fff]; break;
case 8: d=Pico.cram [a&0x003f]; break;
case 4: d=Pico.vsram[a&0x003f]; break;
default:elprintf(EL_ANOMALY, "VDP read with bad type %i", Pico.video.type); break;
}
AutoIncrement();
return d;
}
static int GetDmaLength(void)
{
struct PicoVideo *pvid=&Pico.video;
int len=0;
// 16-bit words to transfer:
len =pvid->reg[0x13];
len|=pvid->reg[0x14]<<8;
// Charles MacDonald:
if(!len) len = 0xffff;
return len;
}
static void DmaSlow(int len)
{
u16 *pd=0, *pdend, *r;
unsigned int a=Pico.video.addr, a2, d;
unsigned char inc=Pico.video.reg[0xf];
unsigned int source;
source =Pico.video.reg[0x15]<<1;
source|=Pico.video.reg[0x16]<<9;
source|=Pico.video.reg[0x17]<<17;
elprintf(EL_VDPDMA, "DmaSlow[%i] %06x->%04x len %i inc=%i blank %i [%i] @ %06x",
Pico.video.type, source, a, len, inc, (Pico.video.status&8)||!(Pico.video.reg[1]&0x40),
SekCyclesDone(), SekPc);
Pico.m.dma_xfers += len;
if ((PicoAHW & PAHW_MCD) && (PicoOpt & POPT_EN_MCD_PSYNC)) SekCyclesBurn(CheckDMA());
else SekEndTimeslice(SekCyclesLeftNoMCD - CheckDMA());
if ((source&0xe00000)==0xe00000) { // Ram
pd=(u16 *)(Pico.ram+(source&0xfffe));
pdend=(u16 *)(Pico.ram+0x10000);
}
else if (PicoAHW & PAHW_MCD)
{
elprintf(EL_VDPDMA, "DmaSlow CD, r3=%02x", Pico_mcd->s68k_regs[3]);
if(source<0x20000) { // Bios area
pd=(u16 *)(Pico_mcd->bios+(source&~1));
pdend=(u16 *)(Pico_mcd->bios+0x20000);
} else if ((source&0xfc0000)==0x200000) { // Word Ram
source -= 2;
if (!(Pico_mcd->s68k_regs[3]&4)) { // 2M mode
pd=(u16 *)(Pico_mcd->word_ram2M+(source&0x3fffe));
pdend=(u16 *)(Pico_mcd->word_ram2M+0x40000);
} else {
if (source < 0x220000) { // 1M mode
int bank = Pico_mcd->s68k_regs[3]&1;
pd=(u16 *)(Pico_mcd->word_ram1M[bank]+(source&0x1fffe));
pdend=(u16 *)(Pico_mcd->word_ram1M[bank]+0x20000);
} else {
DmaSlowCell(source, a, len, inc);
return;
}
}
} else if ((source&0xfe0000)==0x020000) { // Prg Ram
u8 *prg_ram = Pico_mcd->prg_ram_b[Pico_mcd->s68k_regs[3]>>6];
pd=(u16 *)(prg_ram+(source&0x1fffe));
pdend=(u16 *)(prg_ram+0x20000);
} else {
elprintf(EL_VDPDMA|EL_ANOMALY, "DmaSlow[%i] %06x->%04x: FIXME: unsupported src", Pico.video.type, source, a);
return;
}
}
else
{
// if we have DmaHook, let it handle ROM because of possible DMA delay
if (PicoDmaHook && PicoDmaHook(source, len, &pd, &pdend));
else if (source<Pico.romsize) { // Rom
pd=(u16 *)(Pico.rom+(source&~1));
pdend=(u16 *)(Pico.rom+Pico.romsize);
}
else {
elprintf(EL_VDPDMA|EL_ANOMALY, "DmaSlow[%i] %06x->%04x: invalid src", Pico.video.type, source, a);
return;
}
}
// overflow protection, might break something..
if (len > pdend - pd) {
len = pdend - pd;
elprintf(EL_VDPDMA|EL_ANOMALY, "DmaSlow overflow");
}
switch (Pico.video.type)
{
case 1: // vram
r = Pico.vram;
if (inc == 2 && !(a&1) && a+len*2 < 0x10000)
{
// most used DMA mode
memcpy16(r + (a>>1), pd, len);
a += len*2;
}
else
{
for(; len; len--)
{
d=*pd++;
if(a&1) d=(d<<8)|(d>>8);
r[a>>1] = (u16)d; // will drop the upper bits
// AutoIncrement
a=(u16)(a+inc);
// didn't src overlap?
//if(pd >= pdend) pd-=0x8000; // should be good for RAM, bad for ROM
}
}
rendstatus |= PDRAW_DIRTY_SPRITES;
break;
case 3: // cram
Pico.m.dirtyPal = 1;
r = Pico.cram;
for(a2=a&0x7f; len; len--)
{
r[a2>>1] = (u16)*pd++; // bit 0 is ignored
// AutoIncrement
a2+=inc;
// didn't src overlap?
//if(pd >= pdend) pd-=0x8000;
// good dest?
if(a2 >= 0x80) break; // Todds Adventures in Slime World / Andre Agassi tennis
}
a=(a&0xff00)|a2;
break;
case 5: // vsram[a&0x003f]=d;
r = Pico.vsram;
for(a2=a&0x7f; len; len--)
{
r[a2>>1] = (u16)*pd++;
// AutoIncrement
a2+=inc;
// didn't src overlap?
//if(pd >= pdend) pd-=0x8000;
// good dest?
if(a2 >= 0x80) break;
}
a=(a&0xff00)|a2;
break;
default:
elprintf(EL_VDPDMA|EL_ANOMALY, "DMA with bad type %i", Pico.video.type);
break;
}
// remember addr
Pico.video.addr=(u16)a;
}
static void DmaCopy(int len)
{
u16 a=Pico.video.addr;
unsigned char *vr = (unsigned char *) Pico.vram;
unsigned char *vrs;
unsigned char inc=Pico.video.reg[0xf];
int source;
elprintf(EL_VDPDMA, "DmaCopy len %i [%i]", len, SekCyclesDone());
Pico.m.dma_xfers += len;
Pico.video.status |= 2; // dma busy
source =Pico.video.reg[0x15];
source|=Pico.video.reg[0x16]<<8;
vrs=vr+source;
if (source+len > 0x10000) len=0x10000-source; // clip??
for (; len; len--)
{
vr[a] = *vrs++;
// AutoIncrement
a=(u16)(a+inc);
}
// remember addr
Pico.video.addr=a;
rendstatus |= PDRAW_DIRTY_SPRITES;
}
// check: Contra, Megaman
// note: this is still inaccurate
static void DmaFill(int data)
{
int len;
unsigned short a=Pico.video.addr;
unsigned char *vr=(unsigned char *) Pico.vram;
unsigned char high = (unsigned char) (data >> 8);
unsigned char inc=Pico.video.reg[0xf];
len=GetDmaLength();
elprintf(EL_VDPDMA, "DmaFill len %i inc %i [%i]", len, inc, SekCyclesDone());
Pico.m.dma_xfers += len;
Pico.video.status |= 2; // dma busy
// from Charles MacDonald's genvdp.txt:
// Write lower byte to address specified
vr[a] = (unsigned char) data;
a=(u16)(a+inc);
if (!inc) len=1;
for (; len; len--) {
// Write upper byte to adjacent address
// (here we are byteswapped, so address is already 'adjacent')
vr[a] = high;
// Increment address register
a=(u16)(a+inc);
}
// remember addr
Pico.video.addr=a;
// update length
Pico.video.reg[0x13] = Pico.video.reg[0x14] = 0; // Dino Dini's Soccer (E) (by Haze)
rendstatus |= PDRAW_DIRTY_SPRITES;
}
static void CommandDma(void)
{
struct PicoVideo *pvid=&Pico.video;
int len=0,method=0;
if ((pvid->reg[1]&0x10)==0) return; // DMA not enabled
len=GetDmaLength();
method=pvid->reg[0x17]>>6;
if (method< 2) DmaSlow(len); // 68000 to VDP
if (method==3) DmaCopy(len); // VRAM Copy
}
static void CommandChange(void)
{
struct PicoVideo *pvid=&Pico.video;
unsigned int cmd=0,addr=0;
cmd=pvid->command;
// Get type of transfer 0xc0000030 (v/c/vsram read/write)
pvid->type=(unsigned char)(((cmd>>2)&0xc)|(cmd>>30));
// Get address 0x3fff0003
addr =(cmd>>16)&0x3fff;
addr|=(cmd<<14)&0xc000;
pvid->addr=(unsigned short)addr;
// Check for dma:
if (cmd&0x80) CommandDma();
}
static void DrawSync(int blank_on)
{
if (Pico.m.scanline < 224 && !(PicoOpt & POPT_ALT_RENDERER) &&
!PicoSkipFrame && DrawScanline <= Pico.m.scanline) {
//elprintf(EL_ANOMALY, "sync");
PicoDrawSync(Pico.m.scanline, blank_on);
}
}
PICO_INTERNAL_ASM void PicoVideoWrite(unsigned int a,unsigned short d)
{
struct PicoVideo *pvid=&Pico.video;
//if (Pico.m.scanline < 224)
// elprintf(EL_STATUS, "PicoVideoWrite [%06x] %04x", a, d);
a&=0x1c;
if (a==0x00) // Data port 0 or 2
{
// try avoiding the sync..
if (Pico.m.scanline < 224 && (pvid->reg[1]&0x40) &&
!(!pvid->pending &&
((pvid->command & 0xc00000f0) == 0x40000010 && Pico.vsram[pvid->addr>>1] == d))
)
DrawSync(0);
if (pvid->pending) {
CommandChange();
pvid->pending=0;
}
// If a DMA fill has been set up, do it
if ((pvid->command&0x80) && (pvid->reg[1]&0x10) && (pvid->reg[0x17]>>6)==2)
{
DmaFill(d);
}
else
{
// preliminary FIFO emulation for Chaos Engine, The (E)
if (!(pvid->status&8) && (pvid->reg[1]&0x40) && !(PicoOpt&POPT_DIS_VDP_FIFO)) // active display?
{
pvid->status&=~0x200; // FIFO no longer empty
pvid->lwrite_cnt++;
if (pvid->lwrite_cnt >= 4) pvid->status|=0x100; // FIFO full
if (pvid->lwrite_cnt > 4) {
SekCyclesBurn(32); // penalty // 488/12-8
if (SekCycleCnt>=SekCycleAim) SekEndRun(0);
}
elprintf(EL_ASVDP, "VDP data write: %04x [%06x] {%i} #%i @ %06x", d, Pico.video.addr,
Pico.video.type, pvid->lwrite_cnt, SekPc);
}
VideoWrite(d);
}
return;
}
if (a==0x04) // Control (command) port 4 or 6
{
if (pvid->pending)
{
if (d & 0x80) DrawSync(0); // only need sync for DMA
// Low word of command:
pvid->command&=0xffff0000;
pvid->command|=d;
pvid->pending=0;
CommandChange();
}
else
{
if ((d&0xc000)==0x8000)
{
// Register write:
int num=(d>>8)&0x1f;
int dold=pvid->reg[num];
int blank_on = 0;
pvid->type=0; // register writes clear command (else no Sega logo in Golden Axe II)
if (num > 0x0a && !(pvid->reg[1]&4)) {
elprintf(EL_ANOMALY, "%02x written to reg %02x in SMS mode @ %06x", d, num, SekPc);
return;
}
if (num == 1 && !(d&0x40) && SekCyclesLeft > 390) blank_on = 1;
DrawSync(blank_on);
pvid->reg[num]=(unsigned char)d;
switch (num)
{
case 0x00:
elprintf(EL_INTSW, "hint_onoff: %i->%i [%i] pend=%i @ %06x", (dold&0x10)>>4,
(d&0x10)>>4, SekCyclesDone(), (pvid->pending_ints&0x10)>>4, SekPc);
goto update_irq;
case 0x01:
elprintf(EL_INTSW, "vint_onoff: %i->%i [%i] pend=%i @ %06x", (dold&0x20)>>5,
(d&0x20)>>5, SekCyclesDone(), (pvid->pending_ints&0x20)>>5, SekPc);
goto update_irq;
case 0x05:
//elprintf(EL_STATUS, "spritep moved to %04x", (unsigned)(Pico.video.reg[5]&0x7f) << 9);
if (d^dold) rendstatus |= PDRAW_SPRITES_MOVED;
break;
case 0x0c:
// renderers should update their palettes if sh/hi mode is changed
if ((d^dold)&8) Pico.m.dirtyPal = 2;
break;
}
return;
update_irq:
#ifndef EMU_CORE_DEBUG
// update IRQ level
if (!SekShouldInterrupt) // hack
{
int lines, pints, irq=0;
lines = (pvid->reg[1] & 0x20) | (pvid->reg[0] & 0x10);
pints = (pvid->pending_ints&lines);
if (pints & 0x20) irq = 6;
else if (pints & 0x10) irq = 4;
SekInterrupt(irq); // update line
if (irq) SekEndRun(24); // make it delayed
}
#endif
}
else
{
// High word of command:
pvid->command&=0x0000ffff;
pvid->command|=d<<16;
pvid->pending=1;
}
}
}
}
PICO_INTERNAL_ASM unsigned int PicoVideoRead(unsigned int a)
{
a&=0x1c;
if (a==0x04) // control port
{
struct PicoVideo *pv=&Pico.video;
unsigned int d;
d=pv->status;
//if (PicoOpt&POPT_ALT_RENDERER) d|=0x0020; // sprite collision (Shadow of the Beast)
if (SekCyclesLeft < 84+4) d|=0x0004; // H-Blank (Sonic3 vs)
d |= ((pv->reg[1]&0x40)^0x40) >> 3; // set V-Blank if display is disabled
d |= (pv->pending_ints&0x20)<<2; // V-int pending?
if (d&0x100) pv->status&=~0x100; // FIFO no longer full
pv->pending = 0; // ctrl port reads clear write-pending flag (Charles MacDonald)
elprintf(EL_SR, "SR read: %04x @ %06x", d, SekPc);
return d;
}
// H-counter info (based on Generator):
// frame:
// | <- hblank? -> |
// start <416> hint <36> hdisplay <38> end // CPU cycles
// |---------...---------|------------|-------------|
// 0 B6 E4 FF // 40 cells
// 0 93 E8 FF // 32 cells
// Gens (?) v-render
// start <hblank=84> hint hdisplay <404> |
// |---------------------|--------------------------|
// E4 (hc[0x43]==0) 07 B1 // 40
// E8 (hc[0x45]==0) 05 91 // 32
// check: Sonic 3D Blast bonus, Cannon Fodder, Chase HQ II, 3 Ninjas kick back, Road Rash 3, Skitchin', Wheel of Fortune
if ((a&0x1c)==0x08)
{
unsigned int d;
int lineCycles;
lineCycles = (488-SekCyclesLeft)&0x1ff;
if (Pico.video.reg[12]&1)
d = hcounts_40[lineCycles];
else d = hcounts_32[lineCycles];
elprintf(EL_HVCNT, "hv: %02x %02x (%i) @ %06x", d, Pico.video.v_counter, SekCyclesDone(), SekPc);
return d | (Pico.video.v_counter << 8);
}
if (a==0x00) // data port
{
return VideoRead();
}
return 0;
}
unsigned int PicoVideoRead8(unsigned int a)
{
unsigned int d;
a&=0x1d;
switch (a)
{
case 0: return VideoRead() >> 8;
case 1: return VideoRead() & 0xff;
case 4: // control port/status reg
d = Pico.video.status >> 8;
if (d&1) Pico.video.status&=~0x100; // FIFO no longer full
Pico.video.pending = 0;
elprintf(EL_SR, "SR read (h): %02x @ %06x", d, SekPc);
return d;
case 5:
d = Pico.video.status & 0xff;
//if (PicoOpt&POPT_ALT_RENDERER) d|=0x0020; // sprite collision (Shadow of the Beast)
d |= ((Pico.video.reg[1]&0x40)^0x40) >> 3; // set V-Blank if display is disabled
d |= (Pico.video.pending_ints&0x20)<<2; // V-int pending?
if (SekCyclesLeft < 84+4) d |= 4; // H-Blank
Pico.video.pending = 0;
elprintf(EL_SR, "SR read (l): %02x @ %06x", d, SekPc);
return d;
case 8: // hv counter
elprintf(EL_HVCNT, "vcounter: %02x (%i) @ %06x", Pico.video.v_counter, SekCyclesDone(), SekPc);
return Pico.video.v_counter;
case 9:
d = (488-SekCyclesLeft)&0x1ff;
if (Pico.video.reg[12]&1)
d = hcounts_40[d];
else d = hcounts_32[d];
elprintf(EL_HVCNT, "hcounter: %02x (%i) @ %06x", d, SekCyclesDone(), SekPc);
return d;
}
return 0;
}
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