neon_simd.cpp
// crc_simd.cpp - written and placed in the public domain by
// Jeffrey Walton, Uri Blumenthal and Marcel Raad.
//
// This source file uses intrinsics to gain access to ARMv7a and
// ARMv8a NEON instructions. A separate source file is needed
// because additional CXXFLAGS are required to enable the
// appropriate instructions sets in some build configurations.
// For Linux and Unix additional flags are not required.
#include "pch.h"
#include "config.h"
#include "stdcpp.h"
#if (CRYPTOPP_ARM_NEON_HEADER)
# include <arm_neon.h>
#endif
#if (CRYPTOPP_ARM_ACLE_HEADER)
# include <stdint.h>
# include <arm_acle.h>
#endif
#ifdef CRYPTOPP_GNU_STYLE_INLINE_ASSEMBLY
# include <signal.h>
# include <setjmp.h>
#endif
#ifndef EXCEPTION_EXECUTE_HANDLER
# define EXCEPTION_EXECUTE_HANDLER 1
#endif
// Squash MS LNK4221 and libtool warnings
extern const char NEON_SIMD_FNAME[] = __FILE__;
NAMESPACE_BEGIN(CryptoPP)
#ifdef CRYPTOPP_GNU_STYLE_INLINE_ASSEMBLY
extern "C" {
typedef void (*SigHandler)(int);
static jmp_buf s_jmpSIGILL;
static void SigIllHandler(int)
{
longjmp(s_jmpSIGILL, 1);
}
}
#endif // Not CRYPTOPP_MS_STYLE_INLINE_ASSEMBLY
bool CPU_ProbeARMv7()
{
#if defined(__aarch32__) || defined(__aarch64__) || defined(_M_ARM64)
return false;
#elif defined(CRYPTOPP_NO_CPU_FEATURE_PROBES)
return false;
#elif CRYPTOPP_ARM_NEON_AVAILABLE
# if defined(CRYPTOPP_MS_STYLE_INLINE_ASSEMBLY)
volatile bool result = true;
__try
{
// Modern MS hardware is ARMv7
result = true;
}
__except (EXCEPTION_EXECUTE_HANDLER)
{
return false;
}
return result;
# else
// longjmp and clobber warnings. Volatile is required.
// http://github.com/weidai11/cryptopp/issues/24 and http://stackoverflow.com/q/7721854
volatile bool result = true;
volatile SigHandler oldHandler = signal(SIGILL, SigIllHandler);
if (oldHandler == SIG_ERR)
return false;
volatile sigset_t oldMask;
if (sigprocmask(0, NULLPTR, (sigset_t*)&oldMask))
{
signal(SIGILL, oldHandler);
return false;
}
if (setjmp(s_jmpSIGILL))
result = false;
else
{
#if 0
// ARMv7 added movt and movw
int a;
asm volatile("movw %0,%1 \n"
"movt %0,%1 \n"
: "=r"(a) : "i"(0x1234));
00000010 <_Z5test2v>: // ARM
10: e3010234 movw r0, #4660 ; 0x1234
14: e3410234 movt r0, #4660 ; 0x1234
18: e12fff1e bx lr
0000001c <_Z5test3v>: // Thumb
1c: f241 2034 movw r0, #4660 ; 0x1234
20: f2c1 2034 movt r0, #4660 ; 0x1234
24: e12fff1e bx lr
#endif
unsigned int a;
asm volatile (
#if defined(__thumb__)
".inst.n 0xf241, 0x2034 \n\t" // movw r0, 0x1234
".inst.n 0xf2c1, 0x2034 \n\t" // movt r0, 0x1234
"mov %0, r0 \n\t" // mov [a], r0
#else
".inst 0xe3010234 \n\t" // movw r0, 0x1234
".inst 0xe3410234 \n\t" // movt r0, 0x1234
"mov %0, r0 \n\t" // mov [a], r0
#endif
: "=r" (a) : : "r0");
result = (a == 0x12341234);
}
sigprocmask(SIG_SETMASK, (sigset_t*)&oldMask, NULLPTR);
signal(SIGILL, oldHandler);
return result;
# endif
#else
return false;
#endif // CRYPTOPP_ARM_NEON_AVAILABLE
}
bool CPU_ProbeNEON()
{
#if defined(__aarch32__) || defined(__aarch64__) || defined(_M_ARM64)
return true;
#elif defined(CRYPTOPP_NO_CPU_FEATURE_PROBES)
return false;
#elif CRYPTOPP_ARM_NEON_AVAILABLE
# if defined(CRYPTOPP_MS_STYLE_INLINE_ASSEMBLY)
volatile bool result = true;
__try
{
uint32x4_t x = vdupq_n_u32(1);
uint32x4_t y = vshlq_n_u32(x, 4);
word32 z[4]; vst1q_u32(z, y);
return (z[0] & z[1] & z[2] & z[3]) == 16;
}
__except (EXCEPTION_EXECUTE_HANDLER)
{
return false;
}
return result;
# else
// longjmp and clobber warnings. Volatile is required.
// http://github.com/weidai11/cryptopp/issues/24 and http://stackoverflow.com/q/7721854
volatile bool result = true;
volatile SigHandler oldHandler = signal(SIGILL, SigIllHandler);
if (oldHandler == SIG_ERR)
return false;
volatile sigset_t oldMask;
if (sigprocmask(0, NULLPTR, (sigset_t*)&oldMask))
{
signal(SIGILL, oldHandler);
return false;
}
if (setjmp(s_jmpSIGILL))
result = false;
else
{
// This is risky... When we hand encode the instructions
// for vmov.u32 and vshl.u32 we get a SIGILL. Apparently
// we need more than just the instructions. Using
// intrinsics introduces the risk because the whole
// file gets built with ISA options, and the higher ISA
// may escape the try block with the SIGILL guard.
uint32x4_t x = vdupq_n_u32(1);
uint32x4_t y = vshlq_n_u32(x, 4);
word32 z[4]; vst1q_u32(z, y);
result = (z[0] & z[1] & z[2] & z[3]) == 16;
}
sigprocmask(SIG_SETMASK, (sigset_t*)&oldMask, NULLPTR);
signal(SIGILL, oldHandler);
return result;
# endif
#else
return false;
#endif // CRYPTOPP_ARM_NEON_AVAILABLE
}
NAMESPACE_END
config.h
Library configuration file.
word32
unsigned int word32
32-bit unsigned datatype
Definition config_int.h:72
CryptoPP
Crypto++ library namespace.
pch.h
Precompiled header file.
stdcpp.h
Common C++ header files.