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Add bswap intrinsics as documented in the Language Reference

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@25309 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nate Begeman
2006-01-14 01:25:24 +00:00
parent 6283760cd1
commit 6fb3bd6a65
8 changed files with 113 additions and 9 deletions
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26
include/llvm/Support/MathExtras.h
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@@ -79,6 +79,32 @@ inline bool isPowerOf2_64(uint64_t Value) {
return Value && !(Value & (Value - 1LL));
}
// ByteSwap_16 - This function returns a byte-swapped representation of the
// 16-bit argument, Value.
inline unsigned short ByteSwap_16(unsigned short Value) {
unsigned short Hi = Value << 8;
unsigned short Lo = Value >> 8;
return Hi | Lo;
}
// ByteSwap_32 - This function returns a byte-swapped representation of the
// 32-bit argument, Value.
inline unsigned ByteSwap_32(unsigned Value) {
unsigned Byte0 = Value & 0x000000FF;
unsigned Byte1 = Value & 0x0000FF00;
unsigned Byte2 = Value & 0x00FF0000;
unsigned Byte3 = Value & 0xFF000000;
return (Byte0 << 24) | (Byte1 << 8) | (Byte2 >> 8) | (Byte3 >> 24);
}
// ByteSwap_64 - This function returns a byte-swapped representation of the
// 64-bit argument, Value.
inline uint64_t ByteSwap_64(uint64_t Value) {
uint64_t Hi = ByteSwap_32(Value);
uint64_t Lo = ByteSwap_32(Value >> 32);
return (Hi << 32) | Lo;
}
// CountLeadingZeros_32 - this function performs the platform optimal form of
// counting the number of zeros from the most significant bit to the first one
// bit. Ex. CountLeadingZeros_32(0x00F000FF) == 8.