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1.1 root 1: /*
2: Hatari - spec320x32.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, Spec512 to 320xH 32-Bit
8: */
9:
10: static void ConvertSpec512_320x32Bit(void)
11: {
12: Uint32 *edi, *ebp;
13: Uint32 *esi;
14: Uint32 eax, ebx, ecx, edx;
15: Uint32 pixelspace[4]; /* Workspace to store pixels to so can print in right order for Spec512 */
16: int y, x;
17:
18: Spec512_StartFrame(); /* Start frame, track palettes */
19:
20: edx = 0; /* Clear index for loop */
21:
22: for (y = STScreenStartHorizLine; y < STScreenEndHorizLine; y++)
23: {
24:
25: Spec512_StartScanLine(); /* Build up palettes for every 4 pixels, store in 'ScanLinePalettes' */
26: edx = 0; /* Clear index for loop */
27:
28: /* Get screen addresses, 'edi'-ST screen, 'ebp'-Previous ST screen, 'esi'-PC screen */
29: eax = STScreenLineOffset[y] + STScreenLeftSkipBytes; /* Offset for this line + Amount to skip on left hand side */
30: edi = (Uint32 *)((Uint8 *)pSTScreen + eax); /* ST format screen 4-plane 16 colors */
31: ebp = (Uint32 *)((Uint8 *)pSTScreenCopy + eax); /* Previous ST format screen */
32: esi = (Uint32 *)pPCScreenDest; /* PC format screen */
33:
34: x = STScreenWidthBytes >> 3; /* Amount to draw across in 16-pixels (8 bytes) */
35:
36: do /* x-loop */
37: {
38: ebx = *edi; /* Do 16 pixels at one time */
39: ecx = *(edi+1);
40:
41: #if SDL_BYTEORDER == SDL_LIL_ENDIAN
42:
43: /* Convert planes to byte indices - as works in wrong order store to workspace so can read back in order! */
44: LOW_BUILD_PIXELS_0 ; /* Generate 'ecx' as pixels [4,5,6,7] */
45: pixelspace[1] = ecx;
46: LOW_BUILD_PIXELS_1 ; /* Generate 'ecx' as pixels [12,13,14,15] */
47: pixelspace[3] = ecx;
48: LOW_BUILD_PIXELS_2 ; /* Generate 'ecx' as pixels [0,1,2,3] */
49: pixelspace[0] = ecx;
50: LOW_BUILD_PIXELS_3 ; /* Generate 'ecx' as pixels [8,9,10,11] */
51: pixelspace[2] = ecx;
52:
53: /* And plot, the Spec512 is offset by 1 pixel and works on 'chunks' of 4 pixels */
54: /* So, we plot 1_4_4_3 to give 16 pixels, changing palette between */
55: /* (last one is used for first of next 16-pixels) */
56: ecx = pixelspace[0];
57: PLOT_SPEC512_LEFT_LOW_320_32BIT(0) ;
58: Spec512_UpdatePaletteSpan();
59:
60: ecx = *(Uint32 *)(((Uint8 *)pixelspace) + 1);
61: PLOT_SPEC512_MID_320_32BIT(1) ;
62: Spec512_UpdatePaletteSpan();
63:
64: ecx = *(Uint32 *)(((Uint8 *)pixelspace) + 5);
65: PLOT_SPEC512_MID_320_32BIT(5) ;
66: Spec512_UpdatePaletteSpan();
67:
68: ecx = *(Uint32 *)(((Uint8 *)pixelspace) + 9);
69: PLOT_SPEC512_MID_320_32BIT(9) ;
70: Spec512_UpdatePaletteSpan();
71:
72: ecx = *(Uint32 *)(((Uint8 *)pixelspace) + 13);
73: PLOT_SPEC512_END_LOW_320_32BIT(13) ;
74:
75: #else
76:
77: LOW_BUILD_PIXELS_0 ;
78: pixelspace[3] = ecx;
79: LOW_BUILD_PIXELS_1 ;
80: pixelspace[1] = ecx;
81: LOW_BUILD_PIXELS_2 ;
82: pixelspace[2] = ecx;
83: LOW_BUILD_PIXELS_3 ;
84: pixelspace[0] = ecx;
85:
86: ecx = pixelspace[0];
87: PLOT_SPEC512_LEFT_LOW_320_32BIT(0);
88: Spec512_UpdatePaletteSpan();
89:
90: ecx = (pixelspace[0] >> 8) | (((Uint8)pixelspace[1])<<24);
91: PLOT_SPEC512_MID_320_32BIT(1);
92: Spec512_UpdatePaletteSpan();
93:
94: ecx = (pixelspace[1] >> 8) | (((Uint8)pixelspace[2])<<24);
95: PLOT_SPEC512_MID_320_32BIT(5);
96: Spec512_UpdatePaletteSpan();
97:
98: ecx = (pixelspace[2] >> 8) | (((Uint8)pixelspace[3])<<24);
99: PLOT_SPEC512_MID_320_32BIT(9);
100: Spec512_UpdatePaletteSpan();
101:
102: ecx = (pixelspace[3] >> 8);
103: PLOT_SPEC512_END_LOW_320_32BIT(13);
104:
105: #endif
106:
107: esi += 16; /* Next PC pixels */
108: edi += 2; /* Next ST pixels */
109: ebp += 2; /* Next ST copy pixels */
110: }
111: while (--x); /* Loop on X */
112:
113: Spec512_EndScanLine();
114:
115: /* Offset to next line */
116: pPCScreenDest = (((Uint8 *)pPCScreenDest) + PCScreenBytesPerLine);
117: }
118:
119: bScreenContentsChanged = TRUE;
120: }
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