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Annotation of hatari/src/convert/low640x16_spec.c, revision 1.1

1.1     ! root        1: /*
        !             2:   Hatari - low640x16_spec.c
        !             3: 
        !             4:   This file is distributed under the GNU Public License, version 2 or at your
        !             5:   option any later version. Read the file gpl.txt for details.
        !             6: 
        !             7:   Screen conversion, Low Res Spec512 to 640x16Bit
        !             8: */
        !             9: 
        !            10: static void ConvertLowRes_640x16Bit_Spec(void)
        !            11: {
        !            12:        Uint32 *edi, *ebp;
        !            13:        Uint32 *esi;
        !            14:        Uint32 eax;
        !            15:        int y;
        !            16: 
        !            17:        Spec512_StartFrame();            /* Start frame, track palettes */
        !            18: 
        !            19:        for (y = STScreenStartHorizLine; y < STScreenEndHorizLine; y++)
        !            20:        {
        !            21:                eax = STScreenLineOffset[y] + STScreenLeftSkipBytes;  /* Offset for this line + Amount to skip on left hand side */
        !            22:                edi = (Uint32 *)((Uint8 *)pSTScreen + eax);        /* ST format screen 4-plane 16 colors */
        !            23:                ebp = (Uint32 *)((Uint8 *)pSTScreenCopy + eax);    /* Previous ST format screen */
        !            24:                esi = (Uint32 *)pPCScreenDest;                     /* PC format screen */
        !            25: 
        !            26:                Line_ConvertLowRes_640x16Bit_Spec(edi, ebp, esi, eax);
        !            27: 
        !            28:                /* Offset to next line (double on Y) */
        !            29:                pPCScreenDest = (((Uint8 *)pPCScreenDest) + PCScreenBytesPerLine * 2);
        !            30:        }
        !            31: 
        !            32:         bScreenContentsChanged = true;
        !            33: }
        !            34: 
        !            35: 
        !            36: static void Line_ConvertLowRes_640x16Bit_Spec(Uint32 *edi, Uint32 *ebp, Uint32 *esi, Uint32 eax)
        !            37: {
        !            38:        Uint32 ebx, ecx, edx;
        !            39:        int x, Screen4BytesPerLine;
        !            40:        Uint32 pixelspace[5]; /* Workspace to store pixels to so can print in right order for Spec512 */
        !            41: 
        !            42:        /* on x86, unaligned access macro touches also
        !            43:         * next byte, zero it for code checkers
        !            44:         */
        !            45:        pixelspace[4] = 0;
        !            46: 
        !            47:        Spec512_StartScanLine();        /* Build up palettes for every 4 pixels, store in 'ScanLinePalettes' */
        !            48:        edx = 0;                        /* Clear index for loop */
        !            49: 
        !            50:        x = STScreenWidthBytes >> 3;   /* Amount to draw across in 16-pixels (8 bytes) */
        !            51:        Screen4BytesPerLine = PCScreenBytesPerLine/4;
        !            52: 
        !            53:        do  /* x-loop */
        !            54:        {
        !            55:                ebx = *edi;                 /* Do 16 pixels at one time */
        !            56:                ecx = *(edi+1);
        !            57: 
        !            58: #if SDL_BYTEORDER == SDL_BIG_ENDIAN
        !            59:                /* Convert planes to byte indices - as works in wrong order store to workspace so can read back in order! */
        !            60:                LOW_BUILD_PIXELS_0 ;        /* Generate 'ecx' as pixels [12,13,14,15] */
        !            61:                pixelspace[3] = ecx;
        !            62:                LOW_BUILD_PIXELS_1 ;        /* Generate 'ecx' as pixels [4,5,6,7] */
        !            63:                pixelspace[1] = ecx;
        !            64:                LOW_BUILD_PIXELS_2 ;        /* Generate 'ecx' as pixels [8,9,10,11] */
        !            65:                pixelspace[2] = ecx;
        !            66:                LOW_BUILD_PIXELS_3 ;        /* Generate 'ecx' as pixels [0,1,2,3] */
        !            67:                pixelspace[0] = ecx;
        !            68: #else
        !            69:                LOW_BUILD_PIXELS_0 ;        /* Generate 'ecx' as pixels [4,5,6,7] */
        !            70:                pixelspace[1] = ecx;
        !            71:                LOW_BUILD_PIXELS_1 ;        /* Generate 'ecx' as pixels [12,13,14,15] */
        !            72:                pixelspace[3] = ecx;
        !            73:                LOW_BUILD_PIXELS_2 ;        /* Generate 'ecx' as pixels [0,1,2,3] */
        !            74:                pixelspace[0] = ecx;
        !            75:                LOW_BUILD_PIXELS_3 ;        /* Generate 'ecx' as pixels [8,9,10,11] */
        !            76:                pixelspace[2] = ecx;
        !            77: #endif
        !            78:                /* And plot, the Spec512 is offset by 1 pixel and works on 'chunks' of 4 pixels */
        !            79:                /* So, we plot 1_4_4_4_3 to give 16 pixels, changing palette between */
        !            80:                /* (last one is used for first of next 16-pixels) */
        !            81:                if (!bScrDoubleY)           /* Double on Y? */
        !            82:                {
        !            83:                        ecx = pixelspace[0];
        !            84:                        PLOT_SPEC512_LEFT_LOW_640_16BIT(0);
        !            85:                        Spec512_UpdatePaletteSpan();
        !            86: 
        !            87:                        ecx = GET_SPEC512_OFFSET_PIXELS(pixelspace, 1);
        !            88:                        PLOT_SPEC512_MID_640_16BIT(1);
        !            89:                        Spec512_UpdatePaletteSpan();
        !            90: 
        !            91:                        ecx = GET_SPEC512_OFFSET_PIXELS(pixelspace, 5);
        !            92:                        PLOT_SPEC512_MID_640_16BIT(5);
        !            93:                        Spec512_UpdatePaletteSpan();
        !            94: 
        !            95:                        ecx = GET_SPEC512_OFFSET_PIXELS(pixelspace, 9);
        !            96:                        PLOT_SPEC512_MID_640_16BIT(9);
        !            97:                        Spec512_UpdatePaletteSpan();
        !            98: 
        !            99:                        ecx = GET_SPEC512_OFFSET_FINAL_PIXELS(pixelspace);
        !           100:                        PLOT_SPEC512_END_LOW_640_16BIT(13);
        !           101:                }
        !           102:                else
        !           103:                {
        !           104:                        ecx = pixelspace[0];
        !           105:                        PLOT_SPEC512_LEFT_LOW_640_16BIT_DOUBLE_Y(0);
        !           106:                        Spec512_UpdatePaletteSpan();
        !           107: 
        !           108:                        ecx = GET_SPEC512_OFFSET_PIXELS(pixelspace, 1);
        !           109:                        PLOT_SPEC512_MID_640_16BIT_DOUBLE_Y(1);
        !           110:                        Spec512_UpdatePaletteSpan();
        !           111: 
        !           112:                        ecx = GET_SPEC512_OFFSET_PIXELS(pixelspace, 5);
        !           113:                        PLOT_SPEC512_MID_640_16BIT_DOUBLE_Y(5);
        !           114:                        Spec512_UpdatePaletteSpan();
        !           115: 
        !           116:                        ecx = GET_SPEC512_OFFSET_PIXELS(pixelspace, 9);
        !           117:                        PLOT_SPEC512_MID_640_16BIT_DOUBLE_Y(9);
        !           118:                        Spec512_UpdatePaletteSpan();
        !           119: 
        !           120:                        ecx = GET_SPEC512_OFFSET_FINAL_PIXELS(pixelspace);
        !           121:                        PLOT_SPEC512_END_LOW_640_16BIT_DOUBLE_Y(13);
        !           122:                }
        !           123: 
        !           124:                esi += 16;                  /* Next PC pixels */
        !           125:                edi += 2;                   /* Next ST pixels */
        !           126:                ebp += 2;                   /* Next ST copy pixels */
        !           127:        }
        !           128:        while (--x);                    /* Loop on X */
        !           129: 
        !           130:        Spec512_EndScanLine();
        !           131: }

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