forked from mirrors/gecko-dev
101 lines
3.2 KiB
C++
101 lines
3.2 KiB
C++
/* 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
|