GLES2N64 (from mupen64plus-ae) plugin. Compile and run on the OpenPandora

[mupen64plus-pandora.git] / source / gles2n64 / src / CRC.cpp

diff --git a/source/gles2n64/src/CRC.cpp b/source/gles2n64/src/CRC.cpp
new file mode 100644 (file)
index 0000000..9ab38a4
--- /dev/null
+++ b/source/gles2n64/src/CRC.cpp
@@ -0,0 +1,93 @@
+#include "Types.h"
+
+#define CRC32_POLYNOMIAL     0x04C11DB7
+
+#ifdef __CRC_OPT
+unsigned int CRCTable[ 256 * 4];
+#else
+unsigned int CRCTable[ 256 ];
+#endif
+
+u32 Reflect( u32 ref, char ch )
+{
+     u32 value = 0;
+
+     // Swap bit 0 for bit 7
+     // bit 1 for bit 6, etc.
+     for (int i = 1; i < (ch + 1); i++)
+     {
+          if(ref & 1)
+               value |= 1 << (ch - i);
+          ref >>= 1;
+     }
+     return value;
+}
+
+void CRC_BuildTable()
+{
+    u32 crc;
+
+    for (int i = 0; i < 256; i++)
+    {
+        crc = Reflect( i, 8 ) << 24;
+        for (int j = 0; j < 8; j++)
+            crc = (crc << 1) ^ (crc & (1 << 31) ? CRC32_POLYNOMIAL : 0);
+
+        CRCTable[i] = Reflect( crc, 32 );
+    }
+
+#ifdef __CRC_OPT
+    for (int i = 0; i < 256; i++)
+    {
+        for(int j = 0; j < 3; j++)
+        {
+            CRCTable[256*(j+1) + i] = (CRCTable[256*j + i]>>8) ^ CRCTable[CRCTable[256*j + i]&0xFF];
+        }
+    }
+#endif
+
+}
+
+u32 CRC_Calculate( u32 crc, void *buffer, u32 count )
+{
+    u8 *p;
+    u32 orig = crc;
+
+    p = (u8*) buffer;
+
+#ifdef __CRC_OPT
+    while(count > 3)
+    {
+        crc ^= *(unsigned int*) p; p += 4;
+        crc = CRCTable[3*256 + (crc&0xFF)]
+          ^ CRCTable[2*256 + ((crc>>8)&0xFF)]
+          ^ CRCTable[1*256 + ((crc>>16)&0xFF)]
+          ^ CRCTable[0*256 + ((crc>>24))];
+
+        count -= 4;
+    }
+#endif
+
+    while (count--)
+        crc = (crc >> 8) ^ CRCTable[(crc & 0xFF) ^ *p++];
+
+    return crc ^ orig;
+}
+
+u32 CRC_CalculatePalette( u32 crc, void *buffer, u32 count )
+{
+    u8 *p;
+    u32 orig = crc;
+
+    p = (u8*) buffer;
+    while (count--)
+    {
+        crc = (crc >> 8) ^ CRCTable[(crc & 0xFF) ^ *p++];
+        crc = (crc >> 8) ^ CRCTable[(crc & 0xFF) ^ *p++];
+
+        p += 6;
+    }
+
+    return crc ^ orig;
+}
+