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[AArch64] Implement CRC32 texture hashing. 

In a particular hashing heavy scene in Crazy Taxi the Murmur3 hash used 3.11% CPU time.
The new CRC32 hash in the same scene used 1.86%
This was tested on a Nvidia SHIELD Android TV with Cortex-A57s.

This will be a bit slower on the Nexus 9, the Denver CPU core is a bit slower with CRC32 texture hashing than Murmur3 texture hashing.
This commit is contained in:
Ryan Houdek 2015-06-08 01:21:04 -05:00
parent 3a3b782f3c
commit ffe085f5ea
1 changed files with 64 additions and 1 deletions
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65
Source/Core/Common/Hash.cpp
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@ -228,7 +228,7 @@ u64 GetMurmurHash3(const u8 *src, u32 len, u32 samples)
// CRC32 hash using the SSE4.2 instruction
u64 GetCRC32(const u8 *src, u32 len, u32 samples)
{
#if _M_SSE >= 0x402
#if _M_SSE >= 0x402 || defined(_M_ARM_64)
u64 h[4] = { len, 0, 0, 0 };
u32 Step = (len / 8);
const u64 *data = (const u64 *)src;
@ -238,6 +238,9 @@ u64 GetCRC32(const u8 *src, u32 len, u32 samples)
Step = Step / samples;
if (Step < 1)
Step = 1;
#endif
#if _M_SSE >= 0x402
while (data < end - Step * 3)
{
h[0] = _mm_crc32_u64(h[0], data[Step * 0]);
@ -259,12 +262,66 @@ u64 GetCRC32(const u8 *src, u32 len, u32 samples)
memcpy(&temp, end, len & 7);
h[0] = _mm_crc32_u64(h[0], temp);
}
#elif defined(_M_ARM_64)
// We should be able to use intrinsics for this
// Too bad the intrinsics for this instruction was added in GCC 4.9.1
// The Android NDK (as of r10e) only has GCC 4.9
// Once the Android NDK has a newer GCC version, update these to use intrinsics
while (data < end - Step * 3)
{
asm ("crc32x %w[res], %w[two], %x[three]"
: [res] "=r" (h[0])
: [two] "r" (h[0]),
[three] "r" (data[Step * 0]));
asm ("crc32x %w[res], %w[two], %x[three]"
: [res] "=r" (h[1])
: [two] "r" (h[1]),
[three] "r" (data[Step * 1]));
asm ("crc32x %w[res], %w[two], %x[three]"
: [res] "=r" (h[2])
: [two] "r" (h[2]),
[three] "r" (data[Step * 2]));
asm ("crc32x %w[res], %w[two], %x[three]"
: [res] "=r" (h[3])
: [two] "r" (h[3]),
[three] "r" (data[Step * 3]));
data += Step * 4;
}
if (data < end - Step * 0)
asm ("crc32x %w[res], %w[two], %x[three]"
: [res] "=r" (h[0])
: [two] "r" (h[0]),
[three] "r" (data[Step * 0]));
if (data < end - Step * 1)
asm ("crc32x %w[res], %w[two], %x[three]"
: [res] "=r" (h[1])
: [two] "r" (h[1]),
[three] "r" (data[Step * 1]));
if (data < end - Step * 2)
asm ("crc32x %w[res], %w[two], %x[three]"
: [res] "=r" (h[2])
: [two] "r" (h[2]),
[three] "r" (data[Step * 2]));
if (len & 7)
{
u64 temp = 0;
memcpy(&temp, end, len & 7);
asm ("crc32x %w[res], %w[two], %x[three]"
: [res] "=r" (h[0])
: [two] "r" (h[0]),
[three] "r" (temp));
}
#endif
#if _M_SSE >= 0x402 || defined(_M_ARM_64)
// FIXME: is there a better way to combine these partial hashes?
return h[0] + (h[1] << 10) + (h[2] << 21) + (h[3] << 32);
#else
return 0;
#endif
}
@ -532,6 +589,12 @@ void SetHash64Function()
ptrHashFunction = &GetCRC32;
}
else
#elif defined(_M_ARM_64)
if (cpu_info.bCRC32)
{
ptrHashFunction = &GetCRC32;
}
else
#endif
{
ptrHashFunction = &GetMurmurHash3;