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https://github.com/Wiimpathy/HatariWii.git
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99 lines
3.5 KiB
C
99 lines
3.5 KiB
C
/*
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Hatari - low320x16_spec.c
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This file is distributed under the GNU General Public License, version 2
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or at your option any later version. Read the file gpl.txt for details.
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Screen Conversion, Low Res Spec512 to 320x16Bit
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*/
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static void ConvertLowRes_320x16Bit_Spec(void)
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{
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Uint32 *edi, *ebp;
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Uint16 *esi;
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Uint32 eax, ebx, ecx, edx;
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Uint32 pixelspace[5]; /* Workspace to store pixels to so can print in right order for Spec512 */
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int y, x;
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/* on x86, unaligned access macro touches also
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* next byte, zero it for code checkers
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*/
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pixelspace[4] = 0;
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Spec512_StartFrame(); /* Start frame, track palettes */
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for (y = STScreenStartHorizLine; y < STScreenEndHorizLine; y++)
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{
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Spec512_StartScanLine(); /* Build up palettes for every 4 pixels, store in 'ScanLinePalettes' */
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/* Get screen addresses, 'edi'-ST screen, 'ebp'-Previous ST screen, 'esi'-PC screen */
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eax = STScreenLineOffset[y] + STScreenLeftSkipBytes; /* Offset for this line + Amount to skip on left hand side */
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edi = (Uint32 *)((Uint8 *)pSTScreen + eax); /* ST format screen 4-plane 16 colors */
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ebp = (Uint32 *)((Uint8 *)pSTScreenCopy + eax); /* Previous ST format screen */
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esi = (Uint16 *)pPCScreenDest; /* PC format screen */
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x = STScreenWidthBytes >> 3; /* Amount to draw across in 16-pixels (8 bytes) */
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do /* x-loop */
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{
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ebx = *edi; /* Do 16 pixels at one time */
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ecx = *(edi+1);
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#if SDL_BYTEORDER == SDL_BIG_ENDIAN
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/* Convert planes to byte indices - as works in wrong order store to workspace so can read back in order! */
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LOW_BUILD_PIXELS_0 ; /* Generate 'ecx' as pixels [12,13,14,15] */
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pixelspace[3] = ecx;
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LOW_BUILD_PIXELS_1 ; /* Generate 'ecx' as pixels [4,5,6,7] */
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pixelspace[1] = ecx;
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LOW_BUILD_PIXELS_2 ; /* Generate 'ecx' as pixels [8,9,10,11] */
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pixelspace[2] = ecx;
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LOW_BUILD_PIXELS_3 ; /* Generate 'ecx' as pixels [0,1,2,3] */
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pixelspace[0] = ecx;
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#else
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LOW_BUILD_PIXELS_0 ; /* Generate 'ecx' as pixels [4,5,6,7] */
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pixelspace[1] = ecx;
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LOW_BUILD_PIXELS_1 ; /* Generate 'ecx' as pixels [12,13,14,15] */
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pixelspace[3] = ecx;
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LOW_BUILD_PIXELS_2 ; /* Generate 'ecx' as pixels [0,1,2,3] */
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pixelspace[0] = ecx;
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LOW_BUILD_PIXELS_3 ; /* Generate 'ecx' as pixels [8,9,10,11] */
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pixelspace[2] = ecx;
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#endif
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/* And plot, the Spec512 is offset by 1 pixel and works on 'chunks' of 4 pixels */
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/* So, we plot 1_4_4_4_3 to give 16 pixels, changing palette between */
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/* (last one is used for first of next 16-pixels) */
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ecx = pixelspace[0];
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PLOT_SPEC512_LEFT_LOW_320_16BIT(0);
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Spec512_UpdatePaletteSpan();
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ecx = GET_SPEC512_OFFSET_PIXELS(pixelspace, 1);
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PLOT_SPEC512_MID_320_16BIT(1);
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Spec512_UpdatePaletteSpan();
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ecx = GET_SPEC512_OFFSET_PIXELS(pixelspace, 5);
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PLOT_SPEC512_MID_320_16BIT(5);
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Spec512_UpdatePaletteSpan();
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ecx = GET_SPEC512_OFFSET_PIXELS(pixelspace, 9);
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PLOT_SPEC512_MID_320_16BIT(9);
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Spec512_UpdatePaletteSpan();
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ecx = GET_SPEC512_OFFSET_FINAL_PIXELS(pixelspace);
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PLOT_SPEC512_END_LOW_320_16BIT(13);
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esi += 16; /* Next PC pixels */
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edi += 2; /* Next ST pixels */
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ebp += 2; /* Next ST copy pixels */
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}
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while (--x); /* Loop on X */
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Spec512_EndScanLine();
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/* Offset to next line */
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pPCScreenDest = (((Uint8 *)pPCScreenDest) + PCScreenBytesPerLine);
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}
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bScreenContentsChanged = true;
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}
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