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Annotation of hatari/src/convert/high640x8.c, revision 1.1

1.1     ! root        1: // Screen Conversion, High Res to 640x8Bit
        !             2: 
        !             3: void ConvertHighRes_640x8Bit_YLoop(void);
        !             4: void Line_ConvertHighRes_640x8Bit(void);
        !             5: 
        !             6: void ConvertHighRes_640x8Bit(void)
        !             7: {
        !             8: //fprintf(stderr,"FIXME: Screen Conversion, High Res to 640x8Bit\n");
        !             9:  unsigned char *src=pSTScreen;
        !            10:  unsigned char *dst=pPCScreenDest;
        !            11:  int i;
        !            12:  for(i=0; i<640*400/8; i++, src++)
        !            13:   {
        !            14:    if( *src & 128 ) *dst++ = 0;  else  *dst++ = 1;
        !            15:    if( *src & 64 )  *dst++ = 0;  else  *dst++ = 1;
        !            16:    if( *src & 32 )  *dst++ = 0;  else  *dst++ = 1;
        !            17:    if( *src & 16 )  *dst++ = 0;  else  *dst++ = 1;
        !            18:    if( *src & 8 )   *dst++ = 0;  else  *dst++ = 1;
        !            19:    if( *src & 4 )   *dst++ = 0;  else  *dst++ = 1;
        !            20:    if( *src & 2 )   *dst++ = 0;  else  *dst++ = 1;
        !            21:    if( *src & 1 )   *dst++ = 0;  else  *dst++ = 1;
        !            22:   }
        !            23:  bScreenContentsChanged = TRUE;
        !            24: /* FIXME */
        !            25: /*
        !            26:   __asm {
        !            27:     push  ebp
        !            28:     push  edi
        !            29:     push  esi
        !            30:     push  ebx
        !            31: 
        !            32:     mov    edi,[pSTScreen]      // ST format screen 4-plane 16 colours
        !            33:     mov    ebp,[pSTScreenCopy]    // Previous ST format screen
        !            34:     mov    esi,[pPCScreenDest]    // PC format screen, byte per pixel 256 colours
        !            35:     xor    edx,edx        // Clear index for loop
        !            36: 
        !            37:     mov    eax,[STScreenStartHorizLine]
        !            38:     mov    [ScrY],eax      // 200 lines
        !            39:     jmp    ConvertHighRes_640x8Bit_YLoop
        !            40:   }
        !            41: */
        !            42: }
        !            43: 
        !            44: /*
        !            45: NAKED void ConvertHighRes_640x8Bit_YLoop(void)
        !            46: {
        !            47:   __asm {
        !            48:     // NOTE 'ScrUpdateFlag' is already set(to full update or check, no palettes)
        !            49:     jmp    Line_ConvertHighRes_640x8Bit      // 0 palette same, can do check tests
        !            50:   }
        !            51: }
        !            52: NAKED void Line_ConvertHighRes_640x8Bit(void)
        !            53: {
        !            54:   __asm {
        !            55:     mov    [ScrX],40
        !            56: x_loop:
        !            57:     // Do 16 pixels at one time
        !            58:     mov    bx,[edi]
        !            59:     // Full update? or just test changes?
        !            60:     test  [ScrUpdateFlag],0xe0000000
        !            61:     jne    copy_word                // Force
        !            62:     // Does differ?
        !            63:     cmp    bx,[ebp]
        !            64:     je    next_word                // Pixels are same as last frame, so ignore
        !            65: 
        !            66: copy_word:
        !            67:     mov    [bScreenContentsChanged],TRUE
        !            68: 
        !            69:     // Plot in 'wrong-order', as ebx is 68000 endian
        !            70:     HIGH_BUILD_PIXELS_0                // Generate 'ecx' as pixels [4,5,6,7]
        !            71:     PLOT_HIGH_640_8BIT(4)
        !            72:     HIGH_BUILD_PIXELS_1                // Generate 'ecx' as pixels [0,1,2,3]
        !            73:     PLOT_HIGH_640_8BIT(0)
        !            74:     HIGH_BUILD_PIXELS_2                // Generate 'ecx' as pixels [12,13,14,15]
        !            75:     PLOT_HIGH_640_8BIT(12)
        !            76:     HIGH_BUILD_PIXELS_3                // Generate 'ecx' as pixels [8,9,10,11]
        !            77:     PLOT_HIGH_640_8BIT(8)
        !            78: 
        !            79: next_word:
        !            80:     add    esi,16                  // Next PC pixels
        !            81:     add    edi,2                  // Next ST pixels
        !            82:     add    ebp,2                  // Next ST copy pixels
        !            83: 
        !            84:     dec    [ScrX]
        !            85:     jne    x_loop                  // Loop on X
        !            86: 
        !            87:     sub    esi,(40*16)                // Back to start of line
        !            88:     add    esi,[PCScreenBytesPerLine]        // Offset to next line
        !            89: 
        !            90:     inc    [ScrY]
        !            91:     mov    eax,[STScreenEndHorizLine]
        !            92:     cmp    [ScrY],eax
        !            93:     jne    ConvertHighRes_640x8Bit_YLoop      // And on Y
        !            94: 
        !            95:     pop    ebx
        !            96:     pop    esi
        !            97:     pop    edi
        !            98:     pop    ebp
        !            99: 
        !           100:     ret
        !           101:   }
        !           102: }
        !           103: */

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