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buildroot/package/xxhash/0001-PPC64-Fix-VSX-POWER8-support-and-disable-POWER7.patch
Fabrice Fontaine 88458aa4cd package/xxhash: fix build with power7 
Fixes:
 - http://autobuild.buildroot.org/results/b431b05b9fd9b06da041162bf258189eebd12050

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
2019-09-27 22:40:06 +02:00

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From 512b8836658450e73ab9bd876f9500032e25b634 Mon Sep 17 00:00:00 2001
From: "easyaspi314 (Devin)" <easyaspi314@users.noreply.github.com>
Date: Tue, 20 Aug 2019 21:06:11 -0400
Subject: [PATCH] [PPC64] Fix VSX, POWER8 support, and disable POWER7.
The VSX codepath is now working on POWER8 and is fully enabled.
The little endian code has been verified on POWER8E, although
a big endian machine was not available.
This uses vpermxor from POWER8 to shuffle on big endian.
There are a few other fixes as well to unify endian memes.
[Retrieved from:
https://github.com/Cyan4973/xxHash/commit/512b8836658450e73ab9bd876f9500032e25b634]
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
---
xxh3.h | 115 ++++++++++++++++++++++++++++++++++++++++++++-----------
xxhsum.c | 6 ++-
2 files changed, 96 insertions(+), 25 deletions(-)
diff --git a/xxh3.h b/xxh3.h
index 77dc955..d5fede8 100644
--- a/xxh3.h
+++ b/xxh3.h
@@ -91,7 +91,7 @@
&& (defined(__ARM_NEON__) || defined(__ARM_NEON)) \
&& defined(__LITTLE_ENDIAN__) /* ARM big endian is a thing */
# define XXH_VECTOR XXH_NEON
-# elif defined(__PPC64__) && defined(__VSX__) && defined(__GNUC__)
+# elif defined(__PPC64__) && defined(__POWER8_VECTOR__) && defined(__GNUC__)
# define XXH_VECTOR XXH_VSX
# else
# define XXH_VECTOR XXH_SCALAR
@@ -122,24 +122,85 @@
# define XXH_mult32to64(x, y) ((U64)((x) & 0xFFFFFFFF) * (U64)((y) & 0xFFFFFFFF))
#endif
-/* VSX stuff */
+/* VSX stuff. It's a lot because VSX support is mediocre across compilers and
+ * there is a lot of mischief with endianness. */
#if XXH_VECTOR == XXH_VSX
# include <altivec.h>
# undef vector
typedef __vector unsigned long long U64x2;
+typedef __vector unsigned char U8x16;
typedef __vector unsigned U32x4;
+
+#ifndef XXH_VSX_BE
+# ifdef __BIG_ENDIAN__
+# define XXH_VSX_BE 1
+# elif defined(__VEC_ELEMENT_REG_ORDER__) && __VEC_ELEMENT_REG_ORDER__ == __ORDER_BIG_ENDIAN__
+# warning "-maltivec=be is not recommended. Please use native endianness."
+# define XXH_VSX_BE 1
+# else
+# define XXH_VSX_BE 0
+# endif
+#endif
+
+/* We need some helpers for big endian mode. */
+#if XXH_VSX_BE
+/* A wrapper for POWER9's vec_revb. */
+# ifdef __POWER9_VECTOR__
+# define XXH_vec_revb vec_revb
+# else
+XXH_FORCE_INLINE U64x2 XXH_vec_revb(U64x2 val)
+{
+ U8x16 const vByteSwap = { 0x07, 0x06, 0x05, 0x04, 0x03, 0x02, 0x01, 0x00,
+ 0x0F, 0x0E, 0x0D, 0x0C, 0x0B, 0x0A, 0x09, 0x08 };
+ return vec_perm(val, val, vByteSwap);
+}
+# endif
+
+/* Power8 Crypto gives us vpermxor which is very handy for
+ * PPC64EB.
+ *
+ * U8x16 vpermxor(U8x16 a, U8x16 b, U8x16 mask)
+ * {
+ * U8x16 ret;
+ * for (int i = 0; i < 16; i++) {
+ * ret[i] = a[mask[i] & 0xF] ^ b[mask[i] >> 4];
+ * }
+ * return ret;
+ * }
+ *
+ * Because both of the main loops load the key, swap, and xor it with data,
+ * we can combine the key swap into this instruction.
+ */
+# ifdef vec_permxor
+# define XXH_vec_permxor vec_permxor
+# else
+# define XXH_vec_permxor __builtin_crypto_vpermxor
+# endif
+#endif
+/*
+ * Because we reinterpret the multiply, there are endian memes: vec_mulo actually becomes
+ * vec_mule.
+ *
+ * Additionally, the intrinsic wasn't added until GCC 8, despite existing for a while.
+ * Clang has an easy way to control this, we can just use the builtin which doesn't swap.
+ * GCC needs inline assembly. */
+#if __has_builtin(__builtin_altivec_vmuleuw)
+# define XXH_vec_mulo __builtin_altivec_vmulouw
+# define XXH_vec_mule __builtin_altivec_vmuleuw
+#else
/* Adapted from https://github.com/google/highwayhash/blob/master/highwayhash/hh_vsx.h. */
-XXH_FORCE_INLINE U64x2 XXH_vsxMultOdd(U32x4 a, U32x4 b) {
+XXH_FORCE_INLINE U64x2 XXH_vec_mulo(U32x4 a, U32x4 b) {
U64x2 result;
__asm__("vmulouw %0, %1, %2" : "=v" (result) : "v" (a), "v" (b));
return result;
}
-XXH_FORCE_INLINE U64x2 XXH_vsxMultEven(U32x4 a, U32x4 b) {
+XXH_FORCE_INLINE U64x2 XXH_vec_mule(U32x4 a, U32x4 b) {
U64x2 result;
__asm__("vmuleuw %0, %1, %2" : "=v" (result) : "v" (a), "v" (b));
return result;
}
#endif
+#endif
/* ==========================================
@@ -558,38 +619,41 @@ XXH3_accumulate_512( void* XXH_RESTRICT acc,
}
}
-#elif (XXH_VECTOR == XXH_VSX) && 0 /* <=========================== DISABLED : MUST BE VALIDATED */
- /* note : vsx code path currently not tested in CI (limitation of cross-compiler and/or emulator)
- * for vsx code path to be shipped and supported, it is critical to create a CI test for it */
+#elif (XXH_VECTOR == XXH_VSX)
U64x2* const xacc = (U64x2*) acc; /* presumed aligned */
U64x2 const* const xdata = (U64x2 const*) data; /* no alignment restriction */
U64x2 const* const xkey = (U64x2 const*) key; /* no alignment restriction */
U64x2 const v32 = { 32, 32 };
-
+#if XXH_VSX_BE
+ U8x16 const vXorSwap = { 0x07, 0x16, 0x25, 0x34, 0x43, 0x52, 0x61, 0x70,
+ 0x8F, 0x9E, 0xAD, 0xBC, 0xCB, 0xDA, 0xE9, 0xF8 };
+#endif
size_t i;
for (i = 0; i < STRIPE_LEN / sizeof(U64x2); i++) {
/* data_vec = xdata[i]; */
/* key_vec = xkey[i]; */
-#ifdef __BIG_ENDIAN__
+#if XXH_VSX_BE
/* byteswap */
- U64x2 const data_vec = vec_revb(vec_vsx_ld(0, xdata + i)); /* note : vec_revb is power9+ */
- U64x2 const key_vec = vec_revb(vec_vsx_ld(0, xkey + i)); /* note : vec_revb is power9+ */
+ U64x2 const data_vec = XXH_vec_revb(vec_vsx_ld(0, xdata + i));
+ U64x2 const key_raw = vec_vsx_ld(0, xkey + i);
+ /* See comment above. data_key = data_vec ^ swap(xkey[i]); */
+ U64x2 const data_key = (U64x2)XXH_vec_permxor((U8x16)data_vec, (U8x16)key_raw, vXorSwap);
#else
U64x2 const data_vec = vec_vsx_ld(0, xdata + i);
U64x2 const key_vec = vec_vsx_ld(0, xkey + i);
-#endif
U64x2 const data_key = data_vec ^ key_vec;
+#endif
/* shuffled = (data_key << 32) | (data_key >> 32); */
U32x4 const shuffled = (U32x4)vec_rl(data_key, v32);
/* product = ((U64x2)data_key & 0xFFFFFFFF) * ((U64x2)shuffled & 0xFFFFFFFF); */
- U64x2 const product = XXH_vsxMultOdd((U32x4)data_key, shuffled);
-
+ U64x2 const product = XXH_vec_mulo((U32x4)data_key, shuffled);
xacc[i] += product;
if (accWidth == XXH3_acc_64bits) {
xacc[i] += data_vec;
} else { /* XXH3_acc_128bits */
- U64x2 const data_swapped = vec_permi(data_vec, data_vec, 2); /* <===== untested !!! */
+ /* swap high and low halves */
+ U64x2 const data_swapped = vec_xxpermdi(data_vec, data_vec, 2);
xacc[i] += data_swapped;
}
}
@@ -716,26 +780,31 @@ XXH3_scrambleAcc(void* XXH_RESTRICT acc, const void* XXH_RESTRICT key)
U64x2 const v47 = { 47, 47 };
U32x4 const prime = { PRIME32_1, PRIME32_1, PRIME32_1, PRIME32_1 };
size_t i;
-
+#if XXH_VSX_BE
+ /* endian swap */
+ U8x16 const vXorSwap = { 0x07, 0x16, 0x25, 0x34, 0x43, 0x52, 0x61, 0x70,
+ 0x8F, 0x9E, 0xAD, 0xBC, 0xCB, 0xDA, 0xE9, 0xF8 };
+#endif
for (i = 0; i < STRIPE_LEN / sizeof(U64x2); i++) {
U64x2 const acc_vec = xacc[i];
U64x2 const data_vec = acc_vec ^ (acc_vec >> v47);
/* key_vec = xkey[i]; */
-#ifdef __BIG_ENDIAN__
- /* swap 32-bit words */
- U64x2 const key_vec = vec_rl(vec_vsx_ld(0, xkey + i), v32);
+#if XXH_VSX_BE
+ /* swap bytes words */
+ U64x2 const key_raw = vec_vsx_ld(0, xkey + i);
+ U64x2 const data_key = (U64x2)XXH_vec_permxor((U8x16)data_vec, (U8x16)key_raw, vXorSwap);
#else
U64x2 const key_vec = vec_vsx_ld(0, xkey + i);
-#endif
U64x2 const data_key = data_vec ^ key_vec;
+#endif
/* data_key *= PRIME32_1 */
/* prod_lo = ((U64x2)data_key & 0xFFFFFFFF) * ((U64x2)prime & 0xFFFFFFFF); */
- U64x2 const prod_lo = XXH_vsxMultOdd((U32x4)data_key, prime);
+ U64x2 const prod_even = XXH_vec_mule((U32x4)data_key, prime);
/* prod_hi = ((U64x2)data_key >> 32) * ((U64x2)prime >> 32); */
- U64x2 const prod_hi = XXH_vsxMultEven((U32x4)data_key, prime);
- xacc[i] = prod_lo + (prod_hi << v32);
+ U64x2 const prod_odd = XXH_vec_mulo((U32x4)data_key, prime);
+ xacc[i] = prod_odd + (prod_even << v32);
}
#else /* scalar variant of Scrambler - universal */
diff --git a/xxhsum.c b/xxhsum.c
index 19685aa..c979966 100644
--- a/xxhsum.c
+++ b/xxhsum.c
@@ -224,8 +224,10 @@ static unsigned BMK_isLittleEndian(void)
# define ARCH "arm"
# endif
#elif defined(__powerpc64__) || defined(__ppc64__) || defined(__PPC64__)
-# if defined(__GNUC__) && defined(__VSX__)
-# define ARCH "ppc64 + VSX"
+# if defined(__GNUC__) && defined(__POWER9_VECTOR__)
+# define ARCH "ppc64 + POWER9 vector"
+# elif defined(__GNUC__) && defined(__POWER8_VECTOR__)
+# define ARCH "ppc64 + POWER8 vector"
# else
# define ARCH "ppc64"
# endif
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