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Use ARM rev and rbit when appropriate 

We tried to add a ByteReverse(word64) and BitReverse(word64) overloads but GCC was producing bad code for it.
pull/853/head
Jeffrey Walton 2019-05-27 14:27:12 -04:00
parent 81da61fe7b
commit 623059f28c
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GPG Key ID: B36AB348921B1838
1 changed files with 41 additions and 11 deletions
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52
misc.h
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@ -63,10 +63,18 @@
#endif
#if defined(__GNUC__) && defined(__linux__)
#define CRYPTOPP_BYTESWAP_AVAILABLE
#define CRYPTOPP_BYTESWAP_AVAILABLE 1
#include <byteswap.h>
#endif
#if (defined(__GNUC__) || defined(__clang__)) && (__ARM_ARCH >= 6)
#define CRYPTOPP_ARM_BYTEREV_AVAILABLE 1
#endif
#if (defined(__GNUC__) || defined(__clang__)) && (__ARM_ARCH >= 7)
#define CRYPTOPP_ARM_BITREV_AVAILABLE 1
#endif
#if defined(__BMI__)
# include <x86intrin.h>
#endif // GCC and BMI
@ -1984,7 +1992,8 @@ inline unsigned int GetByte(ByteOrder order, T value, unsigned int index)
/// \brief Reverses bytes in a 8-bit value
/// \param value the 8-bit value to reverse
/// \note ByteReverse returns the value passed to it since there is nothing to reverse
/// \note ByteReverse returns the value passed to it since there is nothing to
/// reverse.
inline byte ByteReverse(byte value)
{
return value;
@ -1992,7 +2001,8 @@ inline byte ByteReverse(byte value)
/// \brief Reverses bytes in a 16-bit value
/// \param value the 16-bit value to reverse
/// \details ByteReverse calls bswap if available. Otherwise the function performs a 8-bit rotate on the word16
/// \details ByteReverse calls bswap if available. Otherwise the function
/// performs a 8-bit rotate on the word16.
inline word16 ByteReverse(word16 value)
{
#if defined(CRYPTOPP_BYTESWAP_AVAILABLE)
@ -2006,12 +2016,17 @@ inline word16 ByteReverse(word16 value)
/// \brief Reverses bytes in a 32-bit value
/// \param value the 32-bit value to reverse
/// \details ByteReverse calls bswap if available. Otherwise the function uses a combination of rotates on the word32
/// \details ByteReverse calls bswap if available. Otherwise the function uses
/// a combination of rotates on the word32.
inline word32 ByteReverse(word32 value)
{
#if defined(__GNUC__) && defined(CRYPTOPP_X86_ASM_AVAILABLE)
__asm__ ("bswap %0" : "=r" (value) : "0" (value));
return value;
#elif defined(CRYPTOPP_ARM_BYTEREV_AVAILABLE)
word32 rvalue;
__asm__ ("rev %0, %1" : "=r" (rvalue) : "r" (value));
return rvalue;
#elif defined(CRYPTOPP_BYTESWAP_AVAILABLE)
return bswap_32(value);
#elif defined(__MWERKS__) && TARGET_CPU_PPC
@ -2030,7 +2045,8 @@ inline word32 ByteReverse(word32 value)
/// \brief Reverses bytes in a 64-bit value
/// \param value the 64-bit value to reverse
/// \details ByteReverse calls bswap if available. Otherwise the function uses a combination of rotates on the word64
/// \details ByteReverse calls bswap if available. Otherwise the function uses
/// a combination of rotates on the word64.
inline word64 ByteReverse(word64 value)
{
#if defined(__GNUC__) && defined(CRYPTOPP_X86_ASM_AVAILABLE) && defined(__x86_64__)
@ -2051,7 +2067,7 @@ inline word64 ByteReverse(word64 value)
/// \brief Reverses bits in a 8-bit value
/// \param value the 8-bit value to reverse
/// \details BitReverse performs a combination of shifts on the byte
/// \details BitReverse performs a combination of shifts on the byte.
inline byte BitReverse(byte value)
{
value = byte((value & 0xAA) >> 1) | byte((value & 0x55) << 1);
@ -2061,29 +2077,41 @@ inline byte BitReverse(byte value)
/// \brief Reverses bits in a 16-bit value
/// \param value the 16-bit value to reverse
/// \details BitReverse performs a combination of shifts on the word16
/// \details BitReverse performs a combination of shifts on the word16.
inline word16 BitReverse(word16 value)
{
#if defined(CRYPTOPP_ARM_BITREV_AVAILABLE)
word32 rvalue;
__asm__ ("rbit %0, %1" : "=r" (rvalue) : "r" (word32(value)));
return word16(rvalue >> 16);
#else
value = word16((value & 0xAAAA) >> 1) | word16((value & 0x5555) << 1);
value = word16((value & 0xCCCC) >> 2) | word16((value & 0x3333) << 2);
value = word16((value & 0xF0F0) >> 4) | word16((value & 0x0F0F) << 4);
return ByteReverse(value);
#endif
}
/// \brief Reverses bits in a 32-bit value
/// \param value the 32-bit value to reverse
/// \details BitReverse performs a combination of shifts on the word32
/// \details BitReverse performs a combination of shifts on the word32.
inline word32 BitReverse(word32 value)
{
#if defined(CRYPTOPP_ARM_BITREV_AVAILABLE)
word32 rvalue;
__asm__ ("rbit %0, %1" : "=r" (rvalue) : "r" (value));
return rvalue;
#else
value = word32((value & 0xAAAAAAAA) >> 1) | word32((value & 0x55555555) << 1);
value = word32((value & 0xCCCCCCCC) >> 2) | word32((value & 0x33333333) << 2);
value = word32((value & 0xF0F0F0F0) >> 4) | word32((value & 0x0F0F0F0F) << 4);
return ByteReverse(value);
#endif
}
/// \brief Reverses bits in a 64-bit value
/// \param value the 64-bit value to reverse
/// \details BitReverse performs a combination of shifts on the word64
/// \details BitReverse performs a combination of shifts on the word64.
inline word64 BitReverse(word64 value)
{
#if CRYPTOPP_BOOL_SLOW_WORD64
@ -2111,10 +2139,12 @@ inline T BitReverse(T value)
return (T)BitReverse((word16)value);
else if (sizeof(T) == 4)
return (T)BitReverse((word32)value);
else if (sizeof(T) == 8)
return (T)BitReverse((word64)value);
else
{
CRYPTOPP_ASSERT(sizeof(T) == 8);
return (T)BitReverse((word64)value);
CRYPTOPP_ASSERT(0);
return 0;
}
}