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1.1 root 1: // Screen Conversion, Low Res to 320x16Bit
2:
3: #include <endian.h>
4:
5: void ConvertLowRes_320x16Bit_YLoop(void);
6: void Line_ConvertLowRes_320x16Bit(void);
7:
8: void ConvertLowRes_320x16Bit(void)
9: {
10: unsigned long *edi, *ebp;
11: unsigned short *esi;
12: register unsigned long eax, ebx, ecx, edx;
13:
14: edx=0;
15:
16: Convert_StartFrame(); /* Start frame, track palettes */
17: ScrY = STScreenStartHorizLine; /* Starting line in ST screen */
18:
19: do /* y-loop */
20: {
21: eax = STScreenLineOffset[ScrY] + STScreenLeftSkipBytes; /* Offset for this line + Amount to skip on left hand side */
22: edi = (unsigned long *)((char *)pSTScreen + eax); /* ST format screen 4-plane 16 colours */
23: ebp = (unsigned long *)((char *)pSTScreenCopy + eax); /* Previous ST format screen */
24: esi = (unsigned short *)pPCScreenDest;
25:
26: #if __BYTE_ORDER == 4321
27: AdjustLinePaletteRemapBIGENDIAN();
28: #else
29: AdjustLinePaletteRemap();
30: #endif
31:
32: /*
33: __asm {
34: // Get screen addresses, 'edi'-ST screen, 'ebp'-Previous ST screen, 'esi'-PC screen
35: mov eax,[ScrY]
36: mov eax,STScreenLineOffset[eax*4] // Offset for this line
37: add eax,[STScreenLeftSkipBytes] // Amount to skip on left hand side
38: mov edi,[pSTScreen] // ST format screen 4-plane 16 colours
39: add edi,eax
40: mov ebp,[pSTScreenCopy] // Previous ST format screen
41: add ebp,eax
42: mov esi,[pPCScreenDest] // PC format screen, byte per pixel 256 colours
43:
44: call AdjustLinePaletteRemap // Change palette table, DO NOT corrupt edx,edi,esi or ebp!
45: jmp Line_ConvertLowRes_320x16Bit // 0 palette same, can do check tests
46: }
47: }
48: */
49:
50: /*
51: NAKED void Line_ConvertLowRes_320x16Bit(void)
52: {
53: */
54:
55: ScrX=STScreenWidthBytes>>3; /* Amount to draw across in 16-pixels(8 bytes) */
56: /*
57: __asm {
58: mov eax,[STScreenWidthBytes] // Amount to draw across
59: shr eax,3 // in 16-pixels(8 bytes)
60: mov [ScrX],eax
61: */
62:
63: do /* x-loop */
64: {
65: /* Do 16 pixels at one time */
66: ebx=*edi;
67: ecx=*(edi+1);
68: /* ScrUpdateFlag seems not to be set correctly?! - Thothy */
69: if( 1||(ScrUpdateFlag&0xe0000000) || ebx!=*ebp || ecx!=*(ebp+1) ) /* Does differ? */
70: { /* copy word */
71: /*
72: x_loop:
73:
74: // Do 16 pixels at one time
75: mov ebx,[edi]
76: mov ecx,4[edi]
77: // Full update? or just test changes?
78: test [ScrUpdateFlag],0xe0000000
79: jne copy_word // Force
80: // Does differ?
81: cmp ebx,[ebp]
82: jne copy_word
83: cmp ecx,4[ebp]
84: je next_word // Pixels are same as last frame, so ignore
85: */
86:
87: bScreenContentsChanged=TRUE;
88:
89: /*
90: copy_word:
91: mov [bScreenContentsChanged],TRUE
92: */
93:
94: #if __BYTE_ORDER == 4321
95: /* Plot pixels */
96: LOW_BUILD_PIXELS_0 ; /* Generate 'ecx' as pixels [4,5,6,7] */
97: PLOT_LOW_320_16BIT(12) ;
98: LOW_BUILD_PIXELS_1 ; /* Generate 'ecx' as pixels [12,13,14,15] */
99: PLOT_LOW_320_16BIT(4) ;
100: LOW_BUILD_PIXELS_2 ; /* Generate 'ecx' as pixels [0,1,2,3] */
101: PLOT_LOW_320_16BIT(8) ;
102: LOW_BUILD_PIXELS_3 ; /* Generate 'ecx' as pixels [8,9,10,11] */
103: PLOT_LOW_320_16BIT(0) ;
104: #else
105: /* Plot pixels */
106: LOW_BUILD_PIXELS_0 ; /* Generate 'ecx' as pixels [4,5,6,7] */
107: PLOT_LOW_320_16BIT(4) ;
108: LOW_BUILD_PIXELS_1 ; /* Generate 'ecx' as pixels [12,13,14,15] */
109: PLOT_LOW_320_16BIT(12) ;
110: LOW_BUILD_PIXELS_2 ; /* Generate 'ecx' as pixels [0,1,2,3] */
111: PLOT_LOW_320_16BIT(0) ;
112: LOW_BUILD_PIXELS_3 ; /* Generate 'ecx' as pixels [8,9,10,11] */
113: PLOT_LOW_320_16BIT(8) ;
114: #endif
115: }
116:
117: esi += 16; /* Next PC pixels */
118: edi += 2; /* Next ST pixels */
119: ebp += 2; /* Next ST copy pixels */
120: }
121: while( --ScrX ); /* Loop on X */
122: /*
123: next_word:
124: add esi,16*2 // Next PC pixels
125: add edi,8 // Next ST pixels
126: add ebp,8 // Next ST copy pixels
127:
128: dec [ScrX]
129: jne x_loop // Loop on X
130: */
131:
132: pPCScreenDest = (void *)(((unsigned char *)pPCScreenDest)+PCScreenBytesPerLine); /* Offset to next line */
133: ScrY += 1;
134: }
135: while( ScrY < STScreenEndHorizLine ); /* Loop on Y */
136: /*
137: mov eax,[pPCScreenDest]
138: add eax,[PCScreenBytesPerLine] // Offset to next line
139: mov [pPCScreenDest],eax
140:
141: inc [ScrY]
142: mov eax,[STScreenEndHorizLine]
143: cmp [ScrY],eax
144: jne ConvertLowRes_320x16Bit_YLoop // And on Y
145:
146: pop ebx
147: pop esi
148: pop edi
149: pop ebp
150:
151: ret
152: }
153: */
154: }
155:
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