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Is there any shift right/left operation's implementation for typed_data Int32x4 on dart? #47114
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This tracker is for issues related to:
- Dart core libraries dart:typed_data
I'm working on some crypto algorithms using SIMD on Dart. And I need to shift right all the lanes in Int32x4.
I have read the API Docs, and I have found the and/xor/or bit-wise operaion, but no shiftr/shiftl operaion.
Maybe I can implentment it as follwing:
import 'dart:typed_data';
void _run10000000TimesXorAndShuffle(int x, int y, int z, int w) {
var ope = Int32x4(x, y, z, w);
var ope2 = Int32x4(y, z, w, x);
for (var i = 0; i < 10000000; ++i) {
var c = ope ^ ope2;
c.hashCode;
}
}
void _run10000000TimesShiftRightAndShuffle(int x, int y, int z, int w) {
var ope = Int32x4(x, y, z, w);
for (var i = 0; i < 10000000; ++i) {
var x = ope.x;
var y = ope.y;
var z = ope.z;
var w = ope.w;
var res = Int32x4(x << 1, y << 1, z << 1, w << 1);
res.hashCode;
}
}
void main() {
var start = DateTime.now().millisecondsSinceEpoch;
_run10000000TimesXorAndShuffle(0x918a57a0, 0x2095b753, 0x2041660, 0xe0e98a15);
var end = DateTime.now().millisecondsSinceEpoch;
print(end - start);
start = DateTime.now().millisecondsSinceEpoch;
_run10000000TimesShiftRightAndShuffle(
0x918a57a0, 0x2095b753, 0x2041660, 0xe0e98a15);
end = DateTime.now().millisecondsSinceEpoch;
print(end - start);
}
// 30
// 7660But it seems not efficient as the xor operation. So is there any other way to implement shiftr/shiftl operation on Int32x4, or will dart API add such method?
Activity
lrhn commentedon Sep 6, 2021
There is currently no shift operations on
Int32x4.If all you need is to do a left-shift by one, you can probably get around it as
var res = ope + ope;.Right shift, as you ask for, is much harder to simulate.
licy183 commentedon Sep 6, 2021
So will Dart SDK add such operators in the future? I think this is important for mathematical calculations using SIMD on Dart.