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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:
49:
1.1.1.11! root 50: const char Spec512_rcsid[] = "Hatari $Id: spec512.c,v 1.23 2008/03/19 00:24:44 thothy Exp $";
1.1 root 51:
1.1.1.4 root 52: #include <SDL_byteorder.h>
53:
1.1 root 54: #include "main.h"
1.1.1.9 root 55: #include "cycles.h"
1.1 root 56: #include "int.h"
1.1.1.10 root 57: #include "m68000.h"
1.1 root 58: #include "screen.h"
59: #include "spec512.h"
60: #include "video.h"
1.1.1.10 root 61: #include "configuration.h"
62: #include "trace.h"
1.1 root 63:
1.1.1.9 root 64: /* 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 65: #define MAX_CYCLEPALETTES_PERLINE ((512/4) + 1) /* +1 for the '-1' added as a line's terminator */
1.1.1.9 root 66:
67: /* Store writes to palette by cycles per scan line, colour and index in ST */
68: typedef struct
69: {
1.1.1.10 root 70: int LineCycles; /* Number of cycles into line (MUST be div by 4) */
71: Uint16 Colour; /* ST Colour value */
72: Uint16 Index; /* Index into ST palette (0...15) */
73: }
74: CYCLEPALETTE;
1.1.1.2 root 75:
1.1.1.8 root 76: /* 314k; 1024-bytes per line */
1.1.1.9 root 77: static CYCLEPALETTE CyclePalettes[(MAX_SCANLINES_PER_FRAME+1)*MAX_CYCLEPALETTES_PERLINE];
78: static CYCLEPALETTE *pCyclePalette;
79: static int nCyclePalettes[(MAX_SCANLINES_PER_FRAME+1)]; /* Number of entries in above table for each scanline */
1.1.1.10 root 80: static int nPalettesAccesses; /* Number of times accessed palette registers */
1.1.1.8 root 81: static Uint16 CycleColour;
82: static int CycleColourIndex;
83: static int nScanLine, ScanLineCycleCount;
84: static BOOL bIsSpec512Display;
1.1 root 85:
1.1.1.4 root 86: #if SDL_BYTEORDER == SDL_BIG_ENDIAN
1.1.1.10 root 87: static const int STRGBPalEndianTable[16] =
88: {
89: 0,2,1,3,8,10,9,11,4,6,5,7,12,14,13,15
90: };
1.1.1.4 root 91: #endif
92:
1.1.1.2 root 93:
94: /*-----------------------------------------------------------------------*/
1.1.1.10 root 95: /**
96: * Return TRUE if this frame is a Spectrum 512 style image(MUST be low res/non-mix)
97: */
1.1 root 98: BOOL Spec512_IsImage(void)
99: {
1.1.1.10 root 100: /* Normal Low res screen? */
101: if (STRes == ST_LOW_RES && bIsSpec512Display)
102: return TRUE;
1.1 root 103:
1.1.1.10 root 104: return FALSE;
1.1 root 105: }
106:
1.1.1.2 root 107:
108: /*-----------------------------------------------------------------------*/
1.1.1.10 root 109: /**
110: * We store every palette access in a table to perform Spectrum 512 colour effects
111: * This is cleared on each VBL
112: */
1.1 root 113: void Spec512_StartVBL(void)
114: {
1.1.1.10 root 115: /* Clear number of cycle palettes on each frame */
116: memset(nCyclePalettes, 0x0, sizeof(nCyclePalettes));
117:
118: /* Clear number of times accessed on entry in palette (used to check if is true Spectrum 512 image) */
119: nPalettesAccesses = 0;
120:
121: /* Set as not Spectrum 512 displayed image */
122: bIsSpec512Display = FALSE;
1.1 root 123: }
124:
1.1.1.2 root 125:
126: /*-----------------------------------------------------------------------*/
1.1.1.10 root 127: /**
128: * Store color into table 'CyclePalettes[]' for screen conversion according
129: * to cycles into frame.
130: */
1.1.1.8 root 131: void Spec512_StoreCyclePalette(Uint16 col, Uint32 addr)
1.1 root 132: {
1.1.1.10 root 133: CYCLEPALETTE *pTmpCyclePalette;
134: int FrameCycles, ScanLine, nHorPos;
1.1 root 135:
1.1.1.10 root 136: if (!ConfigureParams.Screen.nSpec512Threshold)
137: return;
1.1.1.4 root 138:
1.1.1.10 root 139: CycleColour = col;
140: CycleColourIndex = (addr-0xff8240)>>1;
1.1 root 141:
1.1.1.10 root 142: /* Find number of cycles into frame */
143: /* FIXME [NP] We should use Cycles_GetCounterOnWriteAccess, but it wouldn't */
144: /* work when using multiple accesses instructions like move.l or movem */
145: /* To correct this, assume a delay of 8 cycles (should give a good approximation */
146: /* of a move.w or movem.l for example) */
147: // FrameCycles = Cycles_GetCounterOnWriteAccess(CYCLES_COUNTER_VIDEO);
148: FrameCycles = Cycles_GetCounter(CYCLES_COUNTER_VIDEO) + 8;
149:
150:
151: /* Find scan line we are currently on and get index into cycle-palette table */
152: ScanLine = FrameCycles / nCyclesPerLine;
1.1.1.11! root 153:
! 154: if (ScanLine > MAX_SCANLINES_PER_FRAME)
! 155: return;
! 156:
1.1.1.10 root 157: pTmpCyclePalette = &CyclePalettes[ (ScanLine*MAX_CYCLEPALETTES_PERLINE) + nCyclePalettes[ScanLine] ];
158:
159: nHorPos = FrameCycles % nCyclesPerLine;
160:
161: /* Do we have a previous entry at the same cycles? If so, 68000 have used a 'move.l' instruction so stagger writes */
162: if (nCyclePalettes[ScanLine] > 0)
163: {
164: /* In case the ST uses a move.l or a movem.l to update colors, we need
165: * to add at least 4 cycles between each color: */
166: if ((pTmpCyclePalette-1)->LineCycles >= nHorPos)
167: nHorPos = (pTmpCyclePalette-1)->LineCycles + 4;
168:
169: if ( nHorPos >= nCyclesPerLine ) /* end of line reached, continue on the next line */
170: {
171: ScanLine++;
172: pTmpCyclePalette = &CyclePalettes[ (ScanLine*MAX_CYCLEPALETTES_PERLINE) + nCyclePalettes[ScanLine] ];
173: nHorPos = nCyclePalettes[ScanLine] * 4; /* 4 cycles per access */
174: }
175: }
176:
177: /* Store palette access */
178: pTmpCyclePalette->LineCycles = nHorPos; /* Cycles into scanline */
179: pTmpCyclePalette->Colour = CycleColour; /* Store ST/STe color RGB */
180: pTmpCyclePalette->Index = CycleColourIndex; /* And index (0...15) */
181:
182: if ( 0 && HATARI_TRACE_LEVEL ( HATARI_TRACE_VIDEO_COLOR ) )
183: {
184: int nFrameCycles = Cycles_GetCounter(CYCLES_COUNTER_VIDEO);;
185: int nLineCycles = nFrameCycles % nCyclesPerLine;
186: 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 ,
187: nFrameCycles, nLineCycles, nHBL, M68000_GetPC(), CurrentInstrCycles );
188: }
189:
190: /* Increment count (this can never overflow as you cannot write to the palette more than 'MAX_CYCLEPALETTES_PERLINE-1' times per scanline) */
191: nCyclePalettes[ScanLine]++;
192:
193: /* Check if program wrote to palette registers multiple times on a frame. */
194: /* If so it must be using a spec512 image or some kind of color cycling. */
195: nPalettesAccesses++;
196: if (nPalettesAccesses >= ConfigureParams.Screen.nSpec512Threshold)
197: {
198: bIsSpec512Display = TRUE;
199: }
1.1 root 200: }
201:
1.1.1.2 root 202:
203: /*-----------------------------------------------------------------------*/
1.1.1.10 root 204: /**
205: * Begin palette calculation for Spectrum 512 style images,
206: */
1.1 root 207: void Spec512_StartFrame(void)
208: {
1.1.1.10 root 209: int i;
1.1 root 210:
1.1.1.10 root 211: /* Set so screen gets full-update when returns from Spectrum 512 display */
212: Screen_SetFullUpdate();
1.1 root 213:
1.1.1.10 root 214: /* Set terminators on each line, so when scan during conversion we know when to stop */
215: for (i = 0; i < (nScanlinesPerFrame+1); i++)
216: {
217: pCyclePalette = &CyclePalettes[ (i*MAX_CYCLEPALETTES_PERLINE) + nCyclePalettes[i] ];
218: pCyclePalette->LineCycles = -1; /* Term */
219: }
220:
221: /* Copy first line palette, kept in 'HBLPalettes' and store to 'STRGBPalette' */
222: for (i = 0; i < 16; i++)
223: {
1.1.1.4 root 224: #if SDL_BYTEORDER == SDL_BIG_ENDIAN
1.1.1.10 root 225: STRGBPalette[STRGBPalEndianTable[i]] = ST2RGB[pHBLPalettes[i]];
1.1.1.4 root 226: #else
1.1.1.10 root 227: STRGBPalette[i] = ST2RGB[pHBLPalettes[i]];
1.1.1.4 root 228: #endif
1.1 root 229:
1.1.1.10 root 230: }
1.1 root 231:
1.1.1.10 root 232: /* Ready for first call to 'Spec512_ScanLine' */
233: nScanLine = 0;
234: if (OverscanMode & OVERSCANMODE_TOP)
235: nScanLine += OVERSCAN_TOP;
236:
237: /* Skip to first line(where start to draw screen from) */
238: for (i = 0; i < (STScreenStartHorizLine+(nStartHBL-OVERSCAN_TOP)); i++)
239: Spec512_ScanWholeLine();
1.1 root 240: }
241:
1.1.1.2 root 242:
243: /*-----------------------------------------------------------------------*/
1.1.1.10 root 244: /**
245: * Scan whole line and build up palette - need to do this so when get to screen line we have
246: * the correct 16 colours set
247: */
1.1 root 248: void Spec512_ScanWholeLine(void)
249: {
1.1.1.10 root 250: /* Store pointer to line of palette cycle writes */
251: pCyclePalette = &CyclePalettes[nScanLine*MAX_CYCLEPALETTES_PERLINE];
252: /* Ready for next scan line */
253: nScanLine++;
254:
255: /* Update palette entries until we reach start of displayed screen */
256: ScanLineCycleCount = 0;
257: Spec512_EndScanLine(); /* Read whole line of palettes and update 'STRGBPalette' */
1.1 root 258: }
259:
1.1.1.2 root 260:
261: /*-----------------------------------------------------------------------*/
1.1.1.10 root 262: /**
263: * Build up palette for this scan line and store in 'ScanLinePalettes'
264: */
1.1 root 265: void Spec512_StartScanLine(void)
266: {
1.1.1.10 root 267: int i;
268: int LineStartCycle;
1.1 root 269:
1.1.1.10 root 270: /* Store pointer to line of palette cycle writes */
271: pCyclePalette = &CyclePalettes[nScanLine*MAX_CYCLEPALETTES_PERLINE];
272: /* Ready for next scan line */
273: nScanLine++;
274:
275: if ( nScanlinesPerFrame == SCANLINES_PER_FRAME_50HZ )
276: LineStartCycle = LINE_START_CYCLE_50; /* The screen was 50 Hz */
277: else
278: LineStartCycle = LINE_START_CYCLE_60; /* The screen was 60 Hz */
279:
280: /* Update palette entries until we reach start of displayed screen */
281: ScanLineCycleCount = 0;
282: // for(i=0; i<((SCREEN_START_CYCLE-16)/4); i++) /* This '16' is as we've already added in the 'move' instruction timing */
283: for (i=0; i<((LineStartCycle-SCREENBYTES_LEFT*2)/4 + 6); i++) /* [NP] '6' is required to align pixels and colors */
284: Spec512_UpdatePaletteSpan(); /* Update palette for this 4-cycle period */
285:
286: /* And skip for left border is not using overscan display to user */
287: for (i=0; i<(STScreenLeftSkipBytes/2); i++) /* Eg, 16 bytes = 32 pixels or 8 palette periods */
288: Spec512_UpdatePaletteSpan();
1.1 root 289: }
290:
1.1.1.2 root 291:
292: /*-----------------------------------------------------------------------*/
1.1.1.10 root 293: /**
294: * Run to end of scan line looking up palettes so 'STRGBPalette' is up-to-date
295: */
1.1 root 296: void Spec512_EndScanLine(void)
297: {
1.1.1.10 root 298: /* Continue to reads palette until complete so have correct version for next line */
299: while (ScanLineCycleCount < nCyclesPerLine)
300: Spec512_UpdatePaletteSpan();
1.1 root 301: }
302:
1.1.1.2 root 303:
304: /*-----------------------------------------------------------------------*/
1.1.1.10 root 305: /**
306: * Update palette for 4-pixels span, storing to 'STRGBPalette'
307: */
1.1 root 308: void Spec512_UpdatePaletteSpan(void)
309: {
1.1.1.10 root 310: if (pCyclePalette->LineCycles == ScanLineCycleCount)
311: {
312: /* Need to update palette with new entry */
1.1.1.4 root 313: #if SDL_BYTEORDER == SDL_BIG_ENDIAN
1.1.1.10 root 314: STRGBPalette[STRGBPalEndianTable[pCyclePalette->Index]] = ST2RGB[pCyclePalette->Colour];
1.1.1.4 root 315: #else
1.1.1.10 root 316: STRGBPalette[pCyclePalette->Index] = ST2RGB[pCyclePalette->Colour];
1.1.1.4 root 317: #endif
1.1.1.10 root 318: pCyclePalette += 1;
319: }
320: ScanLineCycleCount += 4; /* Next 4 cycles */
1.1 root 321: }
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