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#include "ultra64.h"
// Valid addr up to 0x7FF
// It's the address of a block of 0x20 bytes in the mempak
// So that means the whole mempak has a 16-bit address space
u8 __osContAddressCrc(u16 addr) {
u32 addr32 = addr;
u32 ret = 0;
u32 bit;
s32 i;
for (bit = 0x400; bit; bit >>= 1) {
ret <<= 1;
if (addr32 & bit) {
if (ret & 0x20) {
ret ^= 0x14;
} else {
++ret;
}
} else if (ret & 0x20) {
ret ^= 0x15;
}
}
for (i = 0; i < 5; ++i) {
ret <<= 1;
if (ret & 0x20) {
ret ^= 0x15;
}
}
return ret & 0x1F;
}
u8 __osContDataCrc(u8* data) {
s32 ret = 0;
u32 bit;
u32 byte;
for (byte = 0x20; byte; --byte, ++data) {
for (bit = 0x80; bit; bit >>= 1) {
ret <<= 1;
if ((*data & bit) != 0) {
if ((ret & 0x100) != 0) {
ret ^= 0x84;
} else {
++ret;
}
} else if (ret & 0x100) {
ret ^= 0x85;
}
}
}
do {
ret <<= 1;
if (ret & 0x100) {
ret ^= 0x85;
}
++byte;
} while (byte < 8U);
return ret;
}
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