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Annotation of hatari/src/convert/med640x16_spec.c, revision 1.1

1.1     ! root        1: /*
        !             2:   Hatari - med640x16_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, Medium Res Spec512 to 640x16Bit
        !             8: */
        !             9: 
        !            10: static void ConvertMediumRes_640x16Bit_Spec(void)
        !            11: {
        !            12:        Uint32 *edi, *ebp;
        !            13:        Uint16 *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 = (Uint16 *)pPCScreenDest;                     /* PC format screen */
        !            25: 
        !            26:                if (HBLPaletteMasks[y] & 0x00030000)               /* Test resolution */
        !            27:                        Line_ConvertMediumRes_640x16Bit_Spec(edi, ebp, esi, eax);       /* med res line */
        !            28:                else
        !            29:                        Line_ConvertLowRes_640x16Bit_Spec(edi, ebp, (Uint32 *)esi, eax);        /* low res line (double on X) */
        !            30: 
        !            31:                /* Offset to next line (double on Y) */
        !            32:                pPCScreenDest = (((Uint8 *)pPCScreenDest) + PCScreenBytesPerLine * 2);
        !            33:        }
        !            34: 
        !            35:         bScreenContentsChanged = true;
        !            36: }
        !            37: 
        !            38: 
        !            39: static void Line_ConvertMediumRes_640x16Bit_Spec(Uint32 *edi, Uint32 *ebp, Uint16 *esi, Uint32 eax)
        !            40: {
        !            41:        Uint32 ebx, ecx, edx;
        !            42:        int x, Screen4BytesPerLine;
        !            43:        Uint32 pixelspace[5]; /* Workspace to store pixels to so can print in right order for Spec512 */
        !            44: 
        !            45:        /* on x86, unaligned access macro touches also
        !            46:         * next byte, zero it for code checkers
        !            47:         */
        !            48:        pixelspace[4] = 0;
        !            49: 
        !            50:        Spec512_StartScanLine();        /* Build up palettes for every 4 pixels, store in 'ScanLinePalettes' */
        !            51:        edx = 0;                        /* Clear index for loop */
        !            52: 
        !            53:        x = STScreenWidthBytes >> 2;   /* Amount to draw across in 16-pixels (4 bytes) */
        !            54:        Screen4BytesPerLine = PCScreenBytesPerLine/2;
        !            55: 
        !            56:        do  /* x-loop */
        !            57:        {
        !            58:                /* Do 16 pixels at one time */
        !            59:                ebx = *edi;
        !            60: 
        !            61: 
        !            62: #if SDL_BYTEORDER == SDL_BIG_ENDIAN
        !            63:                /* Plot in 'right-order' on big endian systems */
        !            64:                MED_BUILD_PIXELS_0 ;              /* Generate 'ecx' as pixels [12,13,14,15] */
        !            65:                pixelspace[3] = ecx;
        !            66:                MED_BUILD_PIXELS_1 ;              /* Generate 'ecx' as pixels [4,5,6,7] */
        !            67:                pixelspace[1] = ecx;
        !            68:                MED_BUILD_PIXELS_2 ;              /* Generate 'ecx' as pixels [8,9,10,11] */
        !            69:                pixelspace[2] = ecx;
        !            70:                MED_BUILD_PIXELS_3 ;              /* Generate 'ecx' as pixels [0,1,2,3] */
        !            71:                pixelspace[0] = ecx;
        !            72: #else
        !            73:                /* Plot in 'wrong-order', as ebx is 68000 endian */
        !            74:                MED_BUILD_PIXELS_0 ;              /* Generate 'ecx' as pixels [4,5,6,7] */
        !            75:                pixelspace[1] = ecx;
        !            76:                MED_BUILD_PIXELS_1 ;              /* Generate 'ecx' as pixels [12,13,14,15] */
        !            77:                pixelspace[3] = ecx;
        !            78:                MED_BUILD_PIXELS_2 ;              /* Generate 'ecx' as pixels [0,1,2,3] */
        !            79:                pixelspace[0] = ecx;
        !            80:                MED_BUILD_PIXELS_3 ;              /* Generate 'ecx' as pixels [8,9,10,11] */
        !            81:                pixelspace[2] = ecx;
        !            82: #endif
        !            83:                /* And plot, the Spec512 is offset by 1 pixel and works on 'chunks' of 4 pixels */
        !            84:                /* So, we plot 1_4_4_4_3 to give 16 pixels, changing palette between */
        !            85:                /* (last one is used for first of next 16-pixels) */
        !            86:                /* NOTE : In med res, we display 16 pixels in 8 cycles, so palette should be */
        !            87:                /* updated every 8 pixels, not every 4 pixels (as in low res) */
        !            88:                ecx = pixelspace[0];
        !            89:                if (!bScrDoubleY)       { PLOT_SPEC512_LEFT_MED_640_16BIT(0); }
        !            90:                else                    { PLOT_SPEC512_LEFT_MED_640_16BIT_DOUBLE_Y(0); }
        !            91: //             Spec512_UpdatePaletteSpan();
        !            92: 
        !            93:                ecx = GET_SPEC512_OFFSET_PIXELS(pixelspace, 1);
        !            94:                if (!bScrDoubleY)       { PLOT_SPEC512_MID_MED_640_16BIT(1); }
        !            95:                else                    { PLOT_SPEC512_MID_MED_640_16BIT_DOUBLE_Y(1); }
        !            96:                Spec512_UpdatePaletteSpan();
        !            97: 
        !            98:                ecx = GET_SPEC512_OFFSET_PIXELS(pixelspace, 5);
        !            99:                if (!bScrDoubleY)       { PLOT_SPEC512_MID_MED_640_16BIT(5); }
        !           100:                else                    { PLOT_SPEC512_MID_MED_640_16BIT_DOUBLE_Y(5); }
        !           101: //             Spec512_UpdatePaletteSpan();
        !           102: 
        !           103:                ecx = GET_SPEC512_OFFSET_PIXELS(pixelspace, 9);
        !           104:                if (!bScrDoubleY)       { PLOT_SPEC512_MID_MED_640_16BIT(9); }
        !           105:                else                    { PLOT_SPEC512_MID_MED_640_16BIT_DOUBLE_Y(9); }
        !           106:                Spec512_UpdatePaletteSpan();
        !           107: 
        !           108:                ecx = GET_SPEC512_OFFSET_FINAL_PIXELS(pixelspace);
        !           109:                if (!bScrDoubleY)       { PLOT_SPEC512_END_MED_640_16BIT(13); }
        !           110:                else                    { PLOT_SPEC512_END_MED_640_16BIT_DOUBLE_Y(13); }
        !           111: 
        !           112:                esi += 16;                      /* Next PC pixels */
        !           113:                edi += 1;                       /* Next ST pixels */
        !           114:                ebp += 1;                       /* Next ST copy pixels */
        !           115:        }
        !           116:        while (--x);                        /* Loop on X */
        !           117: 
        !           118:        Spec512_EndScanLine();
        !           119: }

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