more MAME fixes, some optimization

[picodrive.git] / Pico / Utils.c

// This is part of Pico Library\r
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// (c) Copyright 2004 Dave, All rights reserved.\r
// (c) Copyright 2006 notaz, All rights reserved.\r
// Free for non-commercial use.\r
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// For commercial use, separate licencing terms must be obtained.\r
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#include "PicoInt.h"\r
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int PicuAnd=0xf7de;\r
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// Quick low-quality conversion of 320 to 176:\r
int PicuQuick(unsigned short *dest,unsigned short *src)\r
{\r
  unsigned short *end=NULL;\r
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  src+=13; end=src+290;\r
  dest++;\r
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  do\r
  {\r
    *dest++=*src++;\r
    *dest++=*src; src+=2;\r
    *dest++=*src; src+=2;\r
    *dest++=*src++;\r
    *dest++=*src; src+=2;\r
    *dest++=*src; src+=2;\r
  }\r
  while (src<end);\r
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  return 0;\r
}\r
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// Shrink the pixels in src/srcLen, to the screen line pointed to by dest/destLen\r
int PicuShrink(unsigned short *dest,int destLen,unsigned short *src,int srcLen)\r
{\r
  unsigned short *end=NULL;\r
  int bias=0,pa=0,sub=0;\r
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  end=dest+destLen;\r
  sub=srcLen-destLen;\r
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  do\r
  {\r
    pa=*src++; bias-=sub;\r
    if (bias<0) { pa+=*src++; pa>>=1; bias+=destLen; }\r
    *dest++=(unsigned short)pa;\r
\r
    pa=*src++; bias-=sub;\r
    if (bias<0) { pa+=*src++; pa>>=1; bias+=destLen; }\r
    *dest++=(unsigned short)pa;\r
  }\r
  while (dest<end);\r
  \r
  return 0;\r
}\r
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// same thing, only reversed (dest is in pre-decremental mode)\r
int PicuShrinkReverse(unsigned short *dest,int destLen,unsigned short *src,int srcLen)\r
{\r
  unsigned short *end=NULL;\r
  int bias=0,pa=0,sub=0;\r
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  end=dest-destLen;\r
  sub=srcLen-destLen;\r
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  do\r
  {\r
    pa=*src++; bias-=sub;\r
    if (bias<0) { pa+=*src++; pa>>=1; bias+=destLen; }\r
    *(--dest)=(unsigned short)pa;\r
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    pa=*src++; bias-=sub;\r
    if (bias<0) { pa+=*src++; pa>>=1; bias+=destLen; }\r
    *(--dest)=(unsigned short)pa;\r
  }\r
  while (dest>end);\r
  \r
  return 0;\r
}\r
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int PicuMerge(unsigned short *dest,int destLen,unsigned short *src,int srcLen)\r
{\r
  unsigned short *end=NULL;\r
  int bias=0,pa=0,mask=PicuAnd,sub=0;\r
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  end=dest+destLen;\r
  sub=srcLen-destLen;\r
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  do\r
  {\r
    pa=*src++; bias-=sub;\r
    if (bias<0) { pa+=*src++; pa>>=1; bias+=destLen; }\r
    pa&=mask; pa+=(*dest)&mask; pa>>=1;\r
    *dest++=(unsigned short)pa;\r
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    pa=*src++; bias-=sub;\r
    if (bias<0) { pa+=*src++; pa>>=1; bias+=destLen; }\r
    pa&=mask; pa+=(*dest)&mask; pa>>=1;\r
    *dest++=(unsigned short)pa;\r
  }\r
  while (dest<end);\r
  \r
  return 0;\r
}\r
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