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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
// This file should only be compiled if you're on Power ISA.
#include "nscore.h"
#include "nsAlgorithm.h"
#include "nsTextFragmentImpl.h"
#include <algorithm>
#include <altivec.h>
namespace mozilla {
namespace VMX {
int32_t FirstNon8Bit(const char16_t* str, const char16_t* end) {
const uint32_t numUnicharsPerVector = 8;
const uint32_t numCharsPerVector = 16;
// Paranoia. If this assertion is wrong, change the vector loop below.
MOZ_ASSERT((numCharsPerVector / numUnicharsPerVector) == sizeof(char16_t));
typedef Non8BitParameters<sizeof(size_t)> p;
const uint32_t alignMask = p::alignMask();
const size_t mask = p::mask();
const uint32_t numUnicharsPerWord = p::numUnicharsPerWord();
const uint32_t len = end - str;
// i shall count the index in unichars; i2 shall count the index in chars.
uint32_t i = 0;
uint32_t i2 = 0;
// Align ourselves to a 16-byte boundary, as required by VMX loads.
uint32_t alignLen = std::min(
len, uint32_t(((-NS_PTR_TO_UINT32(str)) & 0xf) / sizeof(char16_t)));
if ((len - alignLen) >= numUnicharsPerVector) {
for (; i < alignLen; i++) {
if (str[i] > 255) return i;
}
// Construct a vector of shorts.
#if __LITTLE_ENDIAN__
const vector unsigned short gtcompare =
reinterpret_cast<vector unsigned short>(
vec_mergel(vec_splat_s8(-1), vec_splat_s8(0)));
#else
const vector unsigned short gtcompare =
reinterpret_cast<vector unsigned short>(
vec_mergel(vec_splat_s8(0), vec_splat_s8(-1)));
#endif
const uint32_t vectWalkEnd =
((len - i) / numUnicharsPerVector) * numUnicharsPerVector;
i2 = i * sizeof(char16_t);
while (1) {
vector unsigned short vect;
// Check one VMX register (8 unichars) at a time. The vec_any_gt
// intrinsic does exactly what we want. This loop is manually unrolled;
// it yields notable performance improvements this way.
#define CheckForASCII \
vect = vec_ld(i2, reinterpret_cast<const unsigned short*>(str)); \
if (vec_any_gt(vect, gtcompare)) return i; \
i += numUnicharsPerVector; \
if (!(i < vectWalkEnd)) break; \
i2 += numCharsPerVector;
CheckForASCII CheckForASCII
#undef CheckForASCII
}
} else {
// Align ourselves to a word boundary.
alignLen = std::min(len, uint32_t(((-NS_PTR_TO_UINT32(str)) & alignMask) /
sizeof(char16_t)));
for (; i < alignLen; i++) {
if (str[i] > 255) return i;
}
}
// Check one word at a time.
const uint32_t wordWalkEnd =
((len - i) / numUnicharsPerWord) * numUnicharsPerWord;
for (; i < wordWalkEnd; i += numUnicharsPerWord) {
const size_t word = *reinterpret_cast<const size_t*>(str + i);
if (word & mask) return i;
}
// Take care of the remainder one character at a time.
for (; i < len; i++) {
if (str[i] > 255) {
return i;
}
}
return -1;
}
} // namespace VMX
} // namespace mozilla
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