cd/Memory.s improvements, reset fixed?
[picodrive.git] / Pico / Utils.c
CommitLineData
cc68a136 1// This is part of Pico Library\r
2\r
3// (c) Copyright 2004 Dave, All rights reserved.\r
4// (c) Copyright 2006 notaz, All rights reserved.\r
5// Free for non-commercial use.\r
6\r
7// For commercial use, separate licencing terms must be obtained.\r
8\r
9\r
10#include "PicoInt.h"\r
11\r
12int PicuAnd=0xf7de;\r
13\r
14// Quick low-quality conversion of 320 to 176:\r
15int PicuQuick(unsigned short *dest,unsigned short *src)\r
16{\r
17 unsigned short *end=NULL;\r
18\r
19 src+=13; end=src+290;\r
20 dest++;\r
21\r
22 do\r
23 {\r
24 *dest++=*src++;\r
25 *dest++=*src; src+=2;\r
26 *dest++=*src; src+=2;\r
27 *dest++=*src++;\r
28 *dest++=*src; src+=2;\r
29 *dest++=*src; src+=2;\r
30 }\r
31 while (src<end);\r
32\r
33 return 0;\r
34}\r
35\r
36// Shrink the pixels in src/srcLen, to the screen line pointed to by dest/destLen\r
37int PicuShrink(unsigned short *dest,int destLen,unsigned short *src,int srcLen)\r
38{\r
39 unsigned short *end=NULL;\r
40 int bias=0,pa=0,sub=0;\r
41\r
42 end=dest+destLen;\r
43 sub=srcLen-destLen;\r
44\r
45 do\r
46 {\r
47 pa=*src++; bias-=sub;\r
48 if (bias<0) { pa+=*src++; pa>>=1; bias+=destLen; }\r
49 *dest++=(unsigned short)pa;\r
50\r
51 pa=*src++; bias-=sub;\r
52 if (bias<0) { pa+=*src++; pa>>=1; bias+=destLen; }\r
53 *dest++=(unsigned short)pa;\r
54 }\r
55 while (dest<end);\r
56 \r
57 return 0;\r
58}\r
59\r
60// same thing, only reversed (dest is in pre-decremental mode)\r
61int PicuShrinkReverse(unsigned short *dest,int destLen,unsigned short *src,int srcLen)\r
62{\r
63 unsigned short *end=NULL;\r
64 int bias=0,pa=0,sub=0;\r
65\r
66 end=dest-destLen;\r
67 sub=srcLen-destLen;\r
68\r
69 do\r
70 {\r
71 pa=*src++; bias-=sub;\r
72 if (bias<0) { pa+=*src++; pa>>=1; bias+=destLen; }\r
73 *(--dest)=(unsigned short)pa;\r
74\r
75 pa=*src++; bias-=sub;\r
76 if (bias<0) { pa+=*src++; pa>>=1; bias+=destLen; }\r
77 *(--dest)=(unsigned short)pa;\r
78 }\r
79 while (dest>end);\r
80 \r
81 return 0;\r
82}\r
83\r
84int PicuMerge(unsigned short *dest,int destLen,unsigned short *src,int srcLen)\r
85{\r
86 unsigned short *end=NULL;\r
87 int bias=0,pa=0,mask=PicuAnd,sub=0;\r
88\r
89 end=dest+destLen;\r
90 sub=srcLen-destLen;\r
91\r
92 do\r
93 {\r
94 pa=*src++; bias-=sub;\r
95 if (bias<0) { pa+=*src++; pa>>=1; bias+=destLen; }\r
96 pa&=mask; pa+=(*dest)&mask; pa>>=1;\r
97 *dest++=(unsigned short)pa;\r
98\r
99 pa=*src++; bias-=sub;\r
100 if (bias<0) { pa+=*src++; pa>>=1; bias+=destLen; }\r
101 pa&=mask; pa+=(*dest)&mask; pa>>=1;\r
102 *dest++=(unsigned short)pa;\r
103 }\r
104 while (dest<end);\r
105 \r
106 return 0;\r
107}\r
108\r