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1.1.1.2 root 1: /* Screen Conversion, Spec512 to 320x16Bit */ 1.1 root 2: 1.1.1.5 ! root 3: static void ConvertSpec512_320x16Bit(void) 1.1 root 4: { 1.1.1.2 root 5: Uint32 *edi, *ebp; 6: Uint16 *esi; 1.1.1.5 ! root 7: Uint32 eax, ebx, ecx, edx; ! 8: Uint32 pixelspace[4]; /* Workspace to store pixels to so can print in right order for Spec512 */ ! 9: int y, x; 1.1.1.2 root 10: 11: Spec512_StartFrame(); /* Start frame, track palettes */ 12: 13: edx = 0; /* Clear index for loop */ 14: 1.1.1.5 ! root 15: for (y = STScreenStartHorizLine; y < STScreenEndHorizLine; y++) { 1.1.1.2 root 16: 17: Spec512_StartScanLine(); /* Build up palettes for every 4 pixels, store in 'ScanLinePalettes' */ 18: edx = 0; /* Clear index for loop */ 19: 20: /* Get screen addresses, 'edi'-ST screen, 'ebp'-Previous ST screen, 'esi'-PC screen */ 1.1.1.5 ! root 21: eax = STScreenLineOffset[y] + STScreenLeftSkipBytes; /* Offset for this line + Amount to skip on left hand side */ 1.1.1.2 root 22: edi = (Uint32 *)((Uint8 *)pSTScreen + eax); /* ST format screen 4-plane 16 colours */ 23: ebp = (Uint32 *)((Uint8 *)pSTScreenCopy + eax); /* Previous ST format screen */ 1.1.1.3 root 24: esi = (Uint16 *)pPCScreenDest; /* PC format screen */ 1.1 root 25: 1.1.1.5 ! root 26: x = STScreenWidthBytes>>3; /* Amount to draw across in 16-pixels (8 bytes) */ 1.1.1.2 root 27: 28: do /* x-loop */ 29: { 30: ebx = *edi; /* Do 16 pixels at one time */ 31: ecx = *(edi+1); 1.1 root 32: 1.1.1.4 root 33: #if SDL_BYTEORDER == SDL_LIL_ENDIAN 34: 1.1.1.2 root 35: /* Convert planes to byte indices - as works in wrong order store to workspace so can read back in order! */ 36: LOW_BUILD_PIXELS_0 ; /* Generate 'ecx' as pixels [4,5,6,7] */ 1.1.1.5 ! root 37: pixelspace[1] = ecx; 1.1.1.2 root 38: LOW_BUILD_PIXELS_1 ; /* Generate 'ecx' as pixels [12,13,14,15] */ 1.1.1.5 ! root 39: pixelspace[3] = ecx; 1.1.1.2 root 40: LOW_BUILD_PIXELS_2 ; /* Generate 'ecx' as pixels [0,1,2,3] */ 1.1.1.5 ! root 41: pixelspace[0] = ecx; 1.1.1.2 root 42: LOW_BUILD_PIXELS_3 ; /* Generate 'ecx' as pixels [8,9,10,11] */ 1.1.1.5 ! root 43: pixelspace[2] = ecx; 1.1.1.2 root 44: 1.1.1.3 root 45: /* And plot, the Spec512 is offset by 1 pixel and works on 'chunks' of 4 pixels */ 46: /* So, we plot 1_4_4_3 to give 16 pixels, changing palette between */ 47: /* (last one is used for first of next 16-pixels) */ 1.1.1.5 ! root 48: ecx = pixelspace[0]; 1.1.1.3 root 49: PLOT_SPEC512_LEFT_LOW_320_16BIT(0) ; 50: Spec512_UpdatePaletteSpan(); 51: 1.1.1.5 ! root 52: ecx = *(Uint32 *)( ((Uint8 *)pixelspace)+1 ); 1.1.1.3 root 53: PLOT_SPEC512_MID_320_16BIT(1) ; 54: Spec512_UpdatePaletteSpan(); 55: 1.1.1.5 ! root 56: ecx = *(Uint32 *)( ((Uint8 *)pixelspace)+5 ); 1.1.1.3 root 57: PLOT_SPEC512_MID_320_16BIT(5) ; 58: Spec512_UpdatePaletteSpan(); 59: 1.1.1.5 ! root 60: ecx = *(Uint32 *)( ((Uint8 *)pixelspace)+9 ); 1.1.1.3 root 61: PLOT_SPEC512_MID_320_16BIT(9) ; 62: Spec512_UpdatePaletteSpan(); 63: 1.1.1.5 ! root 64: ecx = *(Uint32 *)( ((Uint8 *)pixelspace)+13 ); 1.1.1.3 root 65: PLOT_SPEC512_END_LOW_320_16BIT(13) ; 66: 1.1.1.4 root 67: #else 68: /* Well, I didn't get the code above working on big-endian machines, too, 69: But I hope the following lines are good enough to also do the job... - THH */ 70: 71: LOW_BUILD_PIXELS_0 ; 1.1.1.5 ! root 72: pixelspace[3] = ecx; 1.1.1.4 root 73: LOW_BUILD_PIXELS_1 ; 1.1.1.5 ! root 74: pixelspace[1] = ecx; 1.1.1.4 root 75: LOW_BUILD_PIXELS_2 ; 1.1.1.5 ! root 76: pixelspace[2] = ecx; 1.1.1.4 root 77: LOW_BUILD_PIXELS_3 ; 1.1.1.5 ! root 78: pixelspace[0] = ecx; 1.1.1.4 root 79: 1.1.1.5 ! root 80: ecx = pixelspace[0]; 1.1.1.4 root 81: PLOT_SPEC512_MID_320_16BIT(0) ; 82: Spec512_UpdatePaletteSpan(); 83: 1.1.1.5 ! root 84: ecx = pixelspace[1]; 1.1.1.4 root 85: PLOT_SPEC512_MID_320_16BIT(4) ; 86: Spec512_UpdatePaletteSpan(); 87: 1.1.1.5 ! root 88: ecx = pixelspace[2]; 1.1.1.4 root 89: PLOT_SPEC512_MID_320_16BIT(8) ; 90: Spec512_UpdatePaletteSpan(); 91: 1.1.1.5 ! root 92: ecx = pixelspace[3]; 1.1.1.4 root 93: PLOT_SPEC512_MID_320_16BIT(12) ; 94: Spec512_UpdatePaletteSpan(); 95: 96: #endif 97: 1.1.1.2 root 98: esi += 16; /* Next PC pixels */ 99: edi += 2; /* Next ST pixels */ 100: ebp += 2; /* Next ST copy pixels */ 101: } 1.1.1.5 ! root 102: while( --x ); /* Loop on X */ 1.1 root 103: 1.1.1.2 root 104: Spec512_EndScanLine(); 1.1 root 105: 1.1.1.5 ! root 106: /* Offset to next line */ ! 107: pPCScreenDest = (void *)(((unsigned char *)pPCScreenDest)+PCScreenBytesPerLine); 1.1.1.2 root 108: } 109: 110: bScreenContentsChanged = TRUE; 1.1 root 111: } 1.1.1.2 root 112:
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