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1.1 root 1: /*
1.1.1.7 root 2: Hatari - spec512.c
1.1 root 3:
1.1.1.7 root 4: This file is distributed under the GNU Public License, version 2 or at
5: your option any later version. Read the file gpl.txt for details.
1.1 root 6:
1.1.1.7 root 7: Handle storing of writes to ST palette using clock-cycle counts. We can use
8: this to accurately any form of Spectrum512 style images - even down to the
9: way the screen colours change on decompression routines in menus!
10:
11: As the 68000 has a 4-clock cycle increment we can only change palette every
12: 4 cycles. This means that on one scanline (512 cycles in 50Hz) we have just
13: 512/4=128 places where palette writes can take place. We keep track of this
14: in a table (storing on each scanline and color writes and the cycles on the
15: scanline where they happen). When we draw the screen we simply keep a
16: cycle-count on the line and check this with our table and update the 16-color
17: palette with each change. As the table is already ordered this makes things
18: very simple. Speed is a problem, though, as the palette can change once every
19: 4 pixels - that's a lot of processing.
1.1 root 20: */
1.1.1.10 root 21:
22:
23: /* 2008/01/12 [NP] In Spec512_StoreCyclePalette, don't use Cycles_GetCounterOnWriteAccess */
24: /* as it doesn't support movem for example. Use Cycles_GetCounter with */
25: /* an average correction of 8 cycles (this should be fixed). */
26: /* In Spec512_StartScanLine, better handling of SCREENBYTES_LEFT when */
27: /* border are present. Better alignement of pixel and color when left */
28: /* border is removed (Rotofull in Nostalgia Demo, When Colors Are Going */
29: /* Bang Bang by DF in Punish Your Machine). */
30: /* 2008/01/13 [NP] In Spec512_StoreCyclePalette, if a movem was used to access several */
31: /* color regs just before the end of a line, the value for nHorPos was not */
32: /* checked and could take values >= 512, which means some colors in the */
33: /* palette were overwritten next time colors were stored on the next line */
34: /* and the palette was not set correctly, especially in the bottom of the */
35: /* screen (Decade Demo Main Menu, Punish Your Machine Main Menu, ULM */
36: /* Hidden Screen in Oh Crickey...). */
37: /* 2008/01/13 [NP] One line should contain 512/4 + 1 colors slots, not 512/4. Else, if */
38: /* a program manages to change colors every 4 cycles, the '-1' terminator */
39: /* added by Spec512_StartFrame will in fact be written on cycle 0 in the */
40: /* next line (this is theorical, practically no program changes the color */
41: /* 128 times per line). */
42: /* Use nCyclesPerLine instead of 512 to check if nHorPos is too big and if */
43: /* the colors must be stored on the next line when freq is 50 or 60Hz */
44: /* (readme.prg by TEX (in 1987)) */
45: /* 2008/01/24 [NP] In Spec512_StartScanLine, use different values for LineStartCycle when */
46: /* running in 50 Hz or 60 Hz (TEX Spectrum Slideshow in 60 Hz). */
47:
48:
1.1.1.12! root 49: const char Spec512_rcsid[] = "Hatari $Id: spec512.c,v 1.30 2008/11/03 22:29:56 npomarede Exp $";
1.1 root 50:
1.1.1.4 root 51: #include <SDL_byteorder.h>
52:
1.1 root 53: #include "main.h"
1.1.1.9 root 54: #include "cycles.h"
1.1 root 55: #include "int.h"
1.1.1.10 root 56: #include "m68000.h"
1.1 root 57: #include "screen.h"
58: #include "spec512.h"
59: #include "video.h"
1.1.1.10 root 60: #include "configuration.h"
1.1.1.12! root 61:
1.1 root 62:
1.1.1.9 root 63: /* As 68000 clock multiple of 4 this mean we can only write to the palette this many time per scanline */
1.1.1.10 root 64: #define MAX_CYCLEPALETTES_PERLINE ((512/4) + 1) /* +1 for the '-1' added as a line's terminator */
1.1.1.9 root 65:
66: /* Store writes to palette by cycles per scan line, colour and index in ST */
67: typedef struct
68: {
1.1.1.10 root 69: int LineCycles; /* Number of cycles into line (MUST be div by 4) */
70: Uint16 Colour; /* ST Colour value */
71: Uint16 Index; /* Index into ST palette (0...15) */
72: }
73: CYCLEPALETTE;
1.1.1.2 root 74:
1.1.1.8 root 75: /* 314k; 1024-bytes per line */
1.1.1.9 root 76: static CYCLEPALETTE CyclePalettes[(MAX_SCANLINES_PER_FRAME+1)*MAX_CYCLEPALETTES_PERLINE];
77: static CYCLEPALETTE *pCyclePalette;
78: static int nCyclePalettes[(MAX_SCANLINES_PER_FRAME+1)]; /* Number of entries in above table for each scanline */
1.1.1.10 root 79: static int nPalettesAccesses; /* Number of times accessed palette registers */
1.1.1.8 root 80: static Uint16 CycleColour;
81: static int CycleColourIndex;
82: static int nScanLine, ScanLineCycleCount;
1.1.1.12! root 83: static bool bIsSpec512Display;
1.1 root 84:
1.1.1.4 root 85: #if SDL_BYTEORDER == SDL_BIG_ENDIAN
1.1.1.10 root 86: static const int STRGBPalEndianTable[16] =
87: {
88: 0,2,1,3,8,10,9,11,4,6,5,7,12,14,13,15
89: };
1.1.1.4 root 90: #endif
91:
1.1.1.2 root 92:
93: /*-----------------------------------------------------------------------*/
1.1.1.10 root 94: /**
95: * Return TRUE if this frame is a Spectrum 512 style image(MUST be low res/non-mix)
96: */
1.1.1.12! root 97: bool Spec512_IsImage(void)
1.1 root 98: {
1.1.1.10 root 99: /* Normal Low res screen? */
100: if (STRes == ST_LOW_RES && bIsSpec512Display)
101: return TRUE;
1.1 root 102:
1.1.1.10 root 103: return FALSE;
1.1 root 104: }
105:
1.1.1.2 root 106:
107: /*-----------------------------------------------------------------------*/
1.1.1.10 root 108: /**
109: * We store every palette access in a table to perform Spectrum 512 colour effects
110: * This is cleared on each VBL
111: */
1.1 root 112: void Spec512_StartVBL(void)
113: {
1.1.1.10 root 114: /* Clear number of cycle palettes on each frame */
115: memset(nCyclePalettes, 0x0, sizeof(nCyclePalettes));
116:
117: /* Clear number of times accessed on entry in palette (used to check if is true Spectrum 512 image) */
118: nPalettesAccesses = 0;
119:
120: /* Set as not Spectrum 512 displayed image */
121: bIsSpec512Display = FALSE;
1.1 root 122: }
123:
1.1.1.2 root 124:
125: /*-----------------------------------------------------------------------*/
1.1.1.10 root 126: /**
127: * Store color into table 'CyclePalettes[]' for screen conversion according
128: * to cycles into frame.
129: */
1.1.1.8 root 130: void Spec512_StoreCyclePalette(Uint16 col, Uint32 addr)
1.1 root 131: {
1.1.1.10 root 132: CYCLEPALETTE *pTmpCyclePalette;
133: int FrameCycles, ScanLine, nHorPos;
1.1 root 134:
1.1.1.10 root 135: if (!ConfigureParams.Screen.nSpec512Threshold)
136: return;
1.1.1.4 root 137:
1.1.1.10 root 138: CycleColour = col;
139: CycleColourIndex = (addr-0xff8240)>>1;
1.1 root 140:
1.1.1.10 root 141: /* Find number of cycles into frame */
142: /* FIXME [NP] We should use Cycles_GetCounterOnWriteAccess, but it wouldn't */
143: /* work when using multiple accesses instructions like move.l or movem */
144: /* To correct this, assume a delay of 8 cycles (should give a good approximation */
145: /* of a move.w or movem.l for example) */
146: // FrameCycles = Cycles_GetCounterOnWriteAccess(CYCLES_COUNTER_VIDEO);
147: FrameCycles = Cycles_GetCounter(CYCLES_COUNTER_VIDEO) + 8;
148:
149:
150: /* Find scan line we are currently on and get index into cycle-palette table */
151: ScanLine = FrameCycles / nCyclesPerLine;
1.1.1.11 root 152:
153: if (ScanLine > MAX_SCANLINES_PER_FRAME)
154: return;
155:
1.1.1.10 root 156: pTmpCyclePalette = &CyclePalettes[ (ScanLine*MAX_CYCLEPALETTES_PERLINE) + nCyclePalettes[ScanLine] ];
157:
158: nHorPos = FrameCycles % nCyclesPerLine;
159:
160: /* Do we have a previous entry at the same cycles? If so, 68000 have used a 'move.l' instruction so stagger writes */
161: if (nCyclePalettes[ScanLine] > 0)
162: {
163: /* In case the ST uses a move.l or a movem.l to update colors, we need
164: * to add at least 4 cycles between each color: */
165: if ((pTmpCyclePalette-1)->LineCycles >= nHorPos)
166: nHorPos = (pTmpCyclePalette-1)->LineCycles + 4;
167:
168: if ( nHorPos >= nCyclesPerLine ) /* end of line reached, continue on the next line */
169: {
170: ScanLine++;
171: pTmpCyclePalette = &CyclePalettes[ (ScanLine*MAX_CYCLEPALETTES_PERLINE) + nCyclePalettes[ScanLine] ];
172: nHorPos = nCyclePalettes[ScanLine] * 4; /* 4 cycles per access */
173: }
174: }
175:
176: /* Store palette access */
177: pTmpCyclePalette->LineCycles = nHorPos; /* Cycles into scanline */
178: pTmpCyclePalette->Colour = CycleColour; /* Store ST/STe color RGB */
179: pTmpCyclePalette->Index = CycleColourIndex; /* And index (0...15) */
180:
181: if ( 0 && HATARI_TRACE_LEVEL ( HATARI_TRACE_VIDEO_COLOR ) )
182: {
183: int nFrameCycles = Cycles_GetCounter(CYCLES_COUNTER_VIDEO);;
184: int nLineCycles = nFrameCycles % nCyclesPerLine;
185: HATARI_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 ,
186: nFrameCycles, nLineCycles, nHBL, M68000_GetPC(), CurrentInstrCycles );
187: }
188:
189: /* Increment count (this can never overflow as you cannot write to the palette more than 'MAX_CYCLEPALETTES_PERLINE-1' times per scanline) */
190: nCyclePalettes[ScanLine]++;
191:
192: /* Check if program wrote to palette registers multiple times on a frame. */
193: /* If so it must be using a spec512 image or some kind of color cycling. */
194: nPalettesAccesses++;
195: if (nPalettesAccesses >= ConfigureParams.Screen.nSpec512Threshold)
196: {
197: bIsSpec512Display = TRUE;
198: }
1.1 root 199: }
200:
1.1.1.2 root 201:
202: /*-----------------------------------------------------------------------*/
1.1.1.10 root 203: /**
204: * Begin palette calculation for Spectrum 512 style images,
205: */
1.1 root 206: void Spec512_StartFrame(void)
207: {
1.1.1.10 root 208: int i;
1.1 root 209:
1.1.1.10 root 210: /* Set so screen gets full-update when returns from Spectrum 512 display */
211: Screen_SetFullUpdate();
1.1 root 212:
1.1.1.10 root 213: /* Set terminators on each line, so when scan during conversion we know when to stop */
214: for (i = 0; i < (nScanlinesPerFrame+1); i++)
215: {
216: pCyclePalette = &CyclePalettes[ (i*MAX_CYCLEPALETTES_PERLINE) + nCyclePalettes[i] ];
217: pCyclePalette->LineCycles = -1; /* Term */
218: }
219:
1.1.1.12! root 220: /* Copy first line palette, kept in 'HBLPalettes' and store to 'STRGBPalette' */
! 221: for (i = 0; i < 16; i++)
! 222: {
1.1.1.4 root 223: #if SDL_BYTEORDER == SDL_BIG_ENDIAN
1.1.1.12! root 224: STRGBPalette[STRGBPalEndianTable[i]] = ST2RGB[pHBLPalettes[i]];
1.1.1.4 root 225: #else
1.1.1.12! root 226: STRGBPalette[i] = ST2RGB[pHBLPalettes[i]];
1.1.1.4 root 227: #endif
1.1.1.12! root 228: }
1.1 root 229:
1.1.1.10 root 230: /* Ready for first call to 'Spec512_ScanLine' */
231: nScanLine = 0;
232: if (OverscanMode & OVERSCANMODE_TOP)
233: nScanLine += OVERSCAN_TOP;
234:
235: /* Skip to first line(where start to draw screen from) */
236: for (i = 0; i < (STScreenStartHorizLine+(nStartHBL-OVERSCAN_TOP)); i++)
237: Spec512_ScanWholeLine();
1.1 root 238: }
239:
1.1.1.2 root 240:
241: /*-----------------------------------------------------------------------*/
1.1.1.10 root 242: /**
243: * Scan whole line and build up palette - need to do this so when get to screen line we have
244: * the correct 16 colours set
245: */
1.1 root 246: void Spec512_ScanWholeLine(void)
247: {
1.1.1.10 root 248: /* Store pointer to line of palette cycle writes */
249: pCyclePalette = &CyclePalettes[nScanLine*MAX_CYCLEPALETTES_PERLINE];
250: /* Ready for next scan line */
251: nScanLine++;
252:
253: /* Update palette entries until we reach start of displayed screen */
254: ScanLineCycleCount = 0;
255: Spec512_EndScanLine(); /* Read whole line of palettes and update 'STRGBPalette' */
1.1 root 256: }
257:
1.1.1.2 root 258:
259: /*-----------------------------------------------------------------------*/
1.1.1.10 root 260: /**
261: * Build up palette for this scan line and store in 'ScanLinePalettes'
262: */
1.1 root 263: void Spec512_StartScanLine(void)
264: {
1.1.1.10 root 265: int i;
266: int LineStartCycle;
1.1 root 267:
1.1.1.10 root 268: /* Store pointer to line of palette cycle writes */
269: pCyclePalette = &CyclePalettes[nScanLine*MAX_CYCLEPALETTES_PERLINE];
270: /* Ready for next scan line */
271: nScanLine++;
272:
273: if ( nScanlinesPerFrame == SCANLINES_PER_FRAME_50HZ )
274: LineStartCycle = LINE_START_CYCLE_50; /* The screen was 50 Hz */
275: else
276: LineStartCycle = LINE_START_CYCLE_60; /* The screen was 60 Hz */
277:
278: /* Update palette entries until we reach start of displayed screen */
279: ScanLineCycleCount = 0;
280: // for(i=0; i<((SCREEN_START_CYCLE-16)/4); i++) /* This '16' is as we've already added in the 'move' instruction timing */
281: for (i=0; i<((LineStartCycle-SCREENBYTES_LEFT*2)/4 + 6); i++) /* [NP] '6' is required to align pixels and colors */
282: Spec512_UpdatePaletteSpan(); /* Update palette for this 4-cycle period */
283:
284: /* And skip for left border is not using overscan display to user */
285: for (i=0; i<(STScreenLeftSkipBytes/2); i++) /* Eg, 16 bytes = 32 pixels or 8 palette periods */
286: Spec512_UpdatePaletteSpan();
1.1 root 287: }
288:
1.1.1.2 root 289:
290: /*-----------------------------------------------------------------------*/
1.1.1.10 root 291: /**
292: * Run to end of scan line looking up palettes so 'STRGBPalette' is up-to-date
293: */
1.1 root 294: void Spec512_EndScanLine(void)
295: {
1.1.1.10 root 296: /* Continue to reads palette until complete so have correct version for next line */
297: while (ScanLineCycleCount < nCyclesPerLine)
298: Spec512_UpdatePaletteSpan();
1.1 root 299: }
300:
1.1.1.2 root 301:
302: /*-----------------------------------------------------------------------*/
1.1.1.10 root 303: /**
304: * Update palette for 4-pixels span, storing to 'STRGBPalette'
305: */
1.1 root 306: void Spec512_UpdatePaletteSpan(void)
307: {
1.1.1.10 root 308: if (pCyclePalette->LineCycles == ScanLineCycleCount)
309: {
310: /* Need to update palette with new entry */
1.1.1.4 root 311: #if SDL_BYTEORDER == SDL_BIG_ENDIAN
1.1.1.10 root 312: STRGBPalette[STRGBPalEndianTable[pCyclePalette->Index]] = ST2RGB[pCyclePalette->Colour];
1.1.1.4 root 313: #else
1.1.1.10 root 314: STRGBPalette[pCyclePalette->Index] = ST2RGB[pCyclePalette->Colour];
1.1.1.4 root 315: #endif
1.1.1.10 root 316: pCyclePalette += 1;
317: }
318: ScanLineCycleCount += 4; /* Next 4 cycles */
1.1 root 319: }
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