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1 | \r |
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2 | // This file is part of the PicoDrive Megadrive Emulator\r |
3 | \r |
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4 | // Copyright (c) 2011 FinalDave (emudave (at) gmail.com)\r |
5 | \r |
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6 | // This code is licensed under the GNU General Public License version 2.0 and the MAME License.\r |
7 | // You can choose the license that has the most advantages for you.\r |
8 | \r |
9 | // SVN repository can be found at http://code.google.com/p/cyclone68000/\r |
10 | \r |
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11 | #include "PicoInt.h"\r |
12 | \r |
13 | static void Byteswap(unsigned char *data,int len)\r |
14 | {\r |
15 | int i=0;\r |
16 | \r |
17 | if (len<2) return; // Too short\r |
18 | \r |
19 | do\r |
20 | {\r |
21 | unsigned short *pd=(unsigned short *)(data+i);\r |
22 | int value=*pd; // Get 2 bytes\r |
23 | \r |
24 | value=(value<<8)|(value>>8); // Byteswap it\r |
25 | *pd=(unsigned short)value; // Put 2b ytes\r |
26 | i+=2;\r |
27 | } \r |
28 | while (i+2<=len);\r |
29 | }\r |
30 | \r |
31 | // Interleve a 16k block and byteswap\r |
32 | static int InterleveBlock(unsigned char *dest,unsigned char *src)\r |
33 | {\r |
34 | int i=0;\r |
35 | for (i=0;i<0x2000;i++) dest[(i<<1) ]=src[ i]; // Odd\r |
36 | for (i=0;i<0x2000;i++) dest[(i<<1)+1]=src[0x2000+i]; // Even\r |
37 | return 0;\r |
38 | }\r |
39 | \r |
40 | // Decode a SMD file\r |
41 | static int DecodeSmd(unsigned char *data,int len)\r |
42 | {\r |
43 | unsigned char *temp=NULL;\r |
44 | int i=0;\r |
45 | \r |
46 | temp=(unsigned char *)malloc(0x4000);\r |
47 | if (temp==NULL) return 1;\r |
48 | memset(temp,0,0x4000);\r |
49 | \r |
50 | // Interleve each 16k block and shift down by 0x200:\r |
51 | for (i=0; i+0x4200<=len; i+=0x4000)\r |
52 | {\r |
53 | InterleveBlock(temp,data+0x200+i); // Interleve 16k to temporary buffer\r |
54 | memcpy(data+i,temp,0x4000); // Copy back in\r |
55 | }\r |
56 | \r |
57 | free(temp);\r |
58 | return 0;\r |
59 | }\r |
60 | \r |
61 | int PicoCartLoad(FILE *f,unsigned char **prom,unsigned int *psize)\r |
62 | {\r |
63 | unsigned char *rom=NULL; int size=0;\r |
64 | if (f==NULL) return 1;\r |
65 | \r |
66 | fseek(f,0,SEEK_END); size=ftell(f); fseek(f,0,SEEK_SET);\r |
67 | \r |
68 | size=(size+3)&~3; // Round up to a multiple of 4\r |
69 | \r |
70 | // Allocate space for the rom plus padding\r |
71 | rom=(unsigned char *)malloc(size+4);\r |
72 | if (rom==NULL) { fclose(f); return 1; }\r |
73 | memset(rom,0,size+4);\r |
74 | \r |
75 | fread(rom,1,size,f); // Load up the rom\r |
76 | fclose(f);\r |
77 | \r |
78 | // Check for SMD:\r |
79 | if ((size&0x3fff)==0x200) { DecodeSmd(rom,size); size-=0x200; } // Decode and byteswap SMD\r |
80 | else Byteswap(rom,size); // Just byteswap\r |
81 | \r |
82 | if (prom) *prom=rom;\r |
83 | if (psize) *psize=size;\r |
84 | \r |
85 | return 0;\r |
86 | }\r |
87 | \r |
88 | // Insert/remove a cartridge:\r |
89 | int PicoCartInsert(unsigned char *rom,unsigned int romsize)\r |
90 | {\r |
91 | // Make sure movie playing/recording is stopped:\r |
92 | if (PmovFile) fclose(PmovFile);\r |
93 | PmovFile=NULL; PmovAction=0;\r |
94 | \r |
95 | memset(&Pico,0,sizeof(Pico)); // Blank Pico state\r |
96 | Pico.rom=rom;\r |
97 | Pico.romsize=romsize;\r |
98 | PicoReset();\r |
99 | \r |
100 | return 0;\r |
101 | }\r |