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HatariWii/src/spec512.c

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/*
Hatari - spec512.c
This file is distributed under the GNU General Public License, version 2
or at your option any later version. Read the file gpl.txt for details.
Handle storing of writes to ST palette using clock-cycle counts. We can use
this to accurately any form of Spectrum512 style images - even down to the
way the screen colours change on decompression routines in menus!
As the 68000 has a 4-clock cycle increment we can only change palette every
4 cycles. This means that on one scanline (512 cycles in 50Hz) we have just
512/4=128 places where palette writes can take place. We keep track of this
in a table (storing on each scanline and color writes and the cycles on the
scanline where they happen). When we draw the screen we simply keep a
cycle-count on the line and check this with our table and update the 16-color
palette with each change. As the table is already ordered this makes things
very simple. Speed is a problem, though, as the palette can change once every
4 pixels - that's a lot of processing.
*/
/* 2008/01/12 [NP] In Spec512_StoreCyclePalette, don't use Cycles_GetCounterOnWriteAccess */
/* as it doesn't support movem for example. Use Cycles_GetCounter with */
/* an average correction of 8 cycles (this should be fixed). */
/* In Spec512_StartScanLine, better handling of SCREENBYTES_LEFT when */
/* border are present. Better alignement of pixel and color when left */
/* border is removed (Rotofull in Nostalgia Demo, When Colors Are Going */
/* Bang Bang by DF in Punish Your Machine). */
/* 2008/01/13 [NP] In Spec512_StoreCyclePalette, if a movem was used to access several */
/* color regs just before the end of a line, the value for nHorPos was not */
/* checked and could take values >= 512, which means some colors in the */
/* palette were overwritten next time colors were stored on the next line */
/* and the palette was not set correctly, especially in the bottom of the */
/* screen (Decade Demo Main Menu, Punish Your Machine Main Menu, ULM */
/* Hidden Screen in Oh Crickey...). */
/* 2008/01/13 [NP] One line should contain 512/4 + 1 colors slots, not 512/4. Else, if */
/* a program manages to change colors every 4 cycles, the '-1' terminator */
/* added by Spec512_StartFrame will in fact be written on cycle 0 in the */
/* next line (this is theorical, practically no program changes the color */
/* 128 times per line). */
/* Use nCyclesPerLine instead of 512 to check if nHorPos is too big and if */
/* the colors must be stored on the next line when freq is 50 or 60Hz */
/* (readme.prg by TEX (in 1987)) */
/* 2008/01/24 [NP] In Spec512_StartScanLine, use different values for LineStartCycle when */
/* running in 50 Hz or 60 Hz (TEX Spectrum Slideshow in 60 Hz). */
/* 2008/12/14 [NP] In Spec512_StoreCyclePalette, instead of approximating write position */
/* by Cycles_GetCounter+8, we use different cases for movem, .l acces and */
/* .w acces (similar to cycles.c). This gives correct results when using */
/* "move.w d0,(a0) or move.w (a0)+,(a1)+" for example, which were shifted */
/* 8 or 4 pixels too late. Calibration was made using a custom program to */
/* compare the results with a real STF in different cases (fix Froggies */
/* Over The Fence Main Menu). */
/* 2008/12/21 [NP] Use BusMode to adjust Cycles_GetCounterOnReadAccess and */
/* Cycles_GetCounterOnWriteAccess depending on who is owning the */
/* bus (cpu, blitter). */
/* 2009/07/28 [NP] Use different timings for movem.l and movem.w */
/* 2014/01/02 [NP] In Spec512_StoreCyclePalette, write occurs during the last cycles for */
/* i_ADD and i_SUB (fix 'add d1,(a0)' in '4-pixel plasma' by TOS Crew). */
const char Spec512_fileid[] = "Hatari spec512.c : " __DATE__ " " __TIME__;
#include <SDL_endian.h>
#include "main.h"
#include "cycles.h"
#include "cycInt.h"
#include "m68000.h"
#include "ioMem.h"
#include "screen.h"
#include "spec512.h"
#include "video.h"
#include "configuration.h"
/* As 68000 clock multiple of 4 this mean we can only write to the palette this many time per scanline */
#define MAX_CYCLEPALETTES_PERLINE ((512/4) + 1) /* +1 for the '-1' added as a line's terminator */
/* Store writes to palette by cycles per scan line, colour and index in ST */
typedef struct
{
int LineCycles; /* Number of cycles into line (MUST be div by 4) */
Uint16 Colour; /* ST Colour value */
Uint16 Index; /* Index into ST palette (0...15) */
}
CYCLEPALETTE;
/* 314k; 1024-bytes per line */
static CYCLEPALETTE CyclePalettes[(MAX_SCANLINES_PER_FRAME+1)*MAX_CYCLEPALETTES_PERLINE];
static CYCLEPALETTE *pCyclePalette;
static int nCyclePalettes[(MAX_SCANLINES_PER_FRAME+1)]; /* Number of entries in above table for each scanline */
static int nPalettesAccesses; /* Number of times accessed palette registers */
static Uint16 CycleColour;
static int CycleColourIndex;
static int nScanLine, ScanLineCycleCount;
static bool bIsSpec512Display;
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
static const int STRGBPalEndianTable[16] =
{
0,2,1,3,8,10,9,11,4,6,5,7,12,14,13,15
};
#endif
/*-----------------------------------------------------------------------*/
/**
* Return true if this frame is a Spectrum 512 style image (can be low/med
* res mix).
*/
bool Spec512_IsImage(void)
{
/* Spec512 mode was triggered in low or med res ? */
if (bIsSpec512Display)
return true;
return false;
}
/*-----------------------------------------------------------------------*/
/**
* We store every palette access in a table to perform Spectrum 512 color
* effects. This is cleared on each VBL.
*/
void Spec512_StartVBL(void)
{
/* Clear number of cycle palettes on each frame */
memset(nCyclePalettes, 0x0, sizeof(nCyclePalettes));
/* Clear number of times accessed on entry in palette (used to check if
* it is true Spectrum 512 image) */
nPalettesAccesses = 0;
/* Set as not Spectrum 512 displayed image */
bIsSpec512Display = false;
}
/*-----------------------------------------------------------------------*/
/**
* Store color into table 'CyclePalettes[]' for screen conversion according
* to cycles into frame.
*/
void Spec512_StoreCyclePalette(Uint16 col, Uint32 addr)
{
CYCLEPALETTE *pTmpCyclePalette;
int FrameCycles, ScanLine, nHorPos;
if (!ConfigureParams.Screen.nSpec512Threshold)
return;
CycleColour = col;
CycleColourIndex = (addr-0xff8240)>>1;
/* Find number of cycles into frame */
/* FIXME [NP] We should use Cycles_GetCounterOnWriteAccess, but it wouldn't */
/* work when using multiple accesses instructions like move.l or movem */
/* To correct this, assume a delay of 8 cycles (should give a good approximation */
/* of a move.w or movem.l for example) */
// FrameCycles = Cycles_GetCounterOnWriteAccess(CYCLES_COUNTER_VIDEO);
if ( BusMode == BUS_MODE_BLITTER )
{
FrameCycles = Cycles_GetCounterOnWriteAccess(CYCLES_COUNTER_VIDEO);
}
else /* BUS_MODE_CPU */
{
#ifdef OLD_CYC_PAL
FrameCycles = Cycles_GetCounter(CYCLES_COUNTER_VIDEO) + 8;
#else
if ( OpcodeFamily == i_MVMLE )
{
// FrameCycles = Cycles_GetCounter(CYCLES_COUNTER_VIDEO) + 8;
FrameCycles = Cycles_GetCounter(CYCLES_COUNTER_VIDEO)
+ (CurrentInstrCycles & ~3);
if (nIoMemAccessSize == SIZE_LONG) /* long access */
FrameCycles -= 0;
else /* word access */
FrameCycles -= 4;
}
else if ( ( OpcodeFamily == i_ADD ) || ( OpcodeFamily == i_SUB ) )
{
FrameCycles = Cycles_GetCounter(CYCLES_COUNTER_VIDEO)
+ (CurrentInstrCycles & ~3);
FrameCycles -= 0; /* write is made at the end, after prefetch */
}
else /* default case write, then prefetch (mostly for 'move') */
{
FrameCycles = Cycles_GetCounter(CYCLES_COUNTER_VIDEO)
+ (CurrentInstrCycles & ~3);
if (nIoMemAccessSize == SIZE_LONG) /* long access */
FrameCycles -= 8;
else /* word/byte access */
FrameCycles -= 4;
}
#endif
}
/* Find scan line we are currently on and get index into cycle-palette table */
Video_ConvertPosition ( FrameCycles , &ScanLine , &nHorPos );
if (ScanLine > MAX_SCANLINES_PER_FRAME)
return;
pTmpCyclePalette = &CyclePalettes[ (ScanLine*MAX_CYCLEPALETTES_PERLINE) + nCyclePalettes[ScanLine] ];
/* Do we have a previous entry at the same cycles? If so, 68000 have used a 'move.l' instruction so stagger writes */
if (nCyclePalettes[ScanLine] > 0)
{
/* In case the ST uses a move.l or a movem.l to update colors, we need
* to add at least 4 cycles between each color: */
if ((pTmpCyclePalette-1)->LineCycles >= nHorPos)
nHorPos = (pTmpCyclePalette-1)->LineCycles + 4;
if ( nHorPos >= nCyclesPerLine ) /* end of line reached, continue on the next line */
{
ScanLine++;
pTmpCyclePalette = &CyclePalettes[ (ScanLine*MAX_CYCLEPALETTES_PERLINE) + nCyclePalettes[ScanLine] ];
nHorPos = nCyclePalettes[ScanLine] * 4; /* 4 cycles per access */
}
}
/* Store palette access */
pTmpCyclePalette->LineCycles = nHorPos; /* Cycles into scanline */
pTmpCyclePalette->Colour = CycleColour; /* Store ST/STe color RGB */
pTmpCyclePalette->Index = CycleColourIndex; /* And index (0...15) */
if ( 0 && LOG_TRACE_LEVEL(TRACE_VIDEO_COLOR))
{
int FrameCycles, HblCounterVideo, LineCycles;
Video_GetPosition ( &FrameCycles , &HblCounterVideo , &LineCycles );
LOG_TRACE_PRINT("spec store col line %d cyc=%d col=%x idx=%d video_cyc=%d %d@%d pc=%x instr_cyc=%d\n",
ScanLine, nHorPos, CycleColour, CycleColourIndex, FrameCycles,
LineCycles, HblCounterVideo, M68000_GetPC(), CurrentInstrCycles);
}
/* Increment count (this can never overflow as you cannot write to the palette more than 'MAX_CYCLEPALETTES_PERLINE-1' times per scanline) */
nCyclePalettes[ScanLine]++;
/* Check if program wrote to palette registers multiple times on a frame. */
/* If so it must be using a spec512 image or some kind of color cycling. */
nPalettesAccesses++;
if (nPalettesAccesses >= ConfigureParams.Screen.nSpec512Threshold)
{
bIsSpec512Display = true;
}
}
/*-----------------------------------------------------------------------*/
/**
* Begin palette calculation for Spectrum 512 style images,
*/
void Spec512_StartFrame(void)
{
int i;
/* Set so screen gets full-update when returns from Spectrum 512 display */
Screen_SetFullUpdate();
/* Set terminators on each line, so when scan during conversion we know when to stop */
for (i = 0; i < (nScanlinesPerFrame+1); i++)
{
pCyclePalette = &CyclePalettes[ (i*MAX_CYCLEPALETTES_PERLINE) + nCyclePalettes[i] ];
pCyclePalette->LineCycles = -1; /* Term */
}
/* Copy first line palette, kept in 'HBLPalettes' and store to 'STRGBPalette' */
for (i = 0; i < 16; i++)
{
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
STRGBPalette[STRGBPalEndianTable[i]] = ST2RGB[pHBLPalettes[i]];
#else
STRGBPalette[i] = ST2RGB[pHBLPalettes[i]];
#endif
}
/* Ready for first call to 'Spec512_ScanLine' */
nScanLine = 0;
if (OverscanMode & OVERSCANMODE_TOP)
nScanLine += OVERSCAN_TOP;
/* Skip to first line(where start to draw screen from) */
for (i = 0; i < (STScreenStartHorizLine+(nStartHBL-OVERSCAN_TOP)); i++)
Spec512_ScanWholeLine();
}
/*-----------------------------------------------------------------------*/
/**
* Scan whole line and build up palette - need to do this so when get to screen line we have
* the correct 16 colours set
*/
void Spec512_ScanWholeLine(void)
{
/* Store pointer to line of palette cycle writes */
pCyclePalette = &CyclePalettes[nScanLine*MAX_CYCLEPALETTES_PERLINE];
/* Ready for next scan line */
nScanLine++;
/* Update palette entries until we reach start of displayed screen */
ScanLineCycleCount = 0;
Spec512_EndScanLine(); /* Read whole line of palettes and update 'STRGBPalette' */
}
/*-----------------------------------------------------------------------*/
/**
* Build up palette for this scan line and store in 'ScanLinePalettes'
*/
void Spec512_StartScanLine(void)
{
int i;
int LineStartCycle;
/* Store pointer to line of palette cycle writes */
pCyclePalette = &CyclePalettes[nScanLine*MAX_CYCLEPALETTES_PERLINE];
/* Ready for next scan line */
nScanLine++;
if ( nScanlinesPerFrame == SCANLINES_PER_FRAME_50HZ )
LineStartCycle = LINE_START_CYCLE_50; /* The screen was 50 Hz */
else
LineStartCycle = LINE_START_CYCLE_60; /* The screen was 60 Hz */
/* Update palette entries until we reach start of displayed screen */
ScanLineCycleCount = 0;
// for(i=0; i<((SCREEN_START_CYCLE-16)/4); i++) /* This '16' is as we've already added in the 'move' instruction timing */
#ifdef OLD_CYC_PAL
for (i=0; i<((LineStartCycle-SCREENBYTES_LEFT*2)/4 + 6); i++) /* [NP] '6' is required to align pixels and colors */
#else
for (i=0; i<((LineStartCycle-SCREENBYTES_LEFT*2)/4 + 7); i++) /* [NP] '7' is required to align pixels and colors */
#endif
Spec512_UpdatePaletteSpan(); /* Update palette for this 4-cycle period */
/* And skip for left border is not using overscan display to user */
for (i=0; i<(STScreenLeftSkipBytes/2); i++) /* Eg, 16 bytes = 32 pixels or 8 palette periods */
Spec512_UpdatePaletteSpan();
}
/*-----------------------------------------------------------------------*/
/**
* Run to end of scan line looking up palettes so 'STRGBPalette' is up-to-date
*/
void Spec512_EndScanLine(void)
{
/* Continue to reads palette until complete so have correct version for next line */
while (ScanLineCycleCount < nCyclesPerLine)
Spec512_UpdatePaletteSpan();
}
/*-----------------------------------------------------------------------*/
/**
* Update palette for 4-pixels span, storing to 'STRGBPalette'
*/
void Spec512_UpdatePaletteSpan(void)
{
if (pCyclePalette->LineCycles == ScanLineCycleCount)
{
/* Need to update palette with new entry */
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
STRGBPalette[STRGBPalEndianTable[pCyclePalette->Index]] = ST2RGB[pCyclePalette->Colour];
#else
STRGBPalette[pCyclePalette->Index] = ST2RGB[pCyclePalette->Colour];
//fprintf ( stderr , "upd spec cyc %d %x %x\n" , ScanLineCycleCount , pCyclePalette->Index , pCyclePalette->Colour );
#endif
pCyclePalette += 1;
}
ScanLineCycleCount += 4; /* Next 4 cycles */
}
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