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Is there a performance difference between i++ and ++i in C++?
... "The pre increment operator introduces a data dependency in the code: the CPU must wait for the increment operation to be completed before its value can be used in the expression. On a deeply pipelined CPU, this introduces a stall. There is no data dependency for the post increment operator." (Game...
How can I build a small operating system on an old desktop computer? [closed]
... you suggest any references to building those?
anything that isn't direct cpu/memory operations. Anything that isn't directly in the CPU reference manual.
After the booting sequence--then what? How do I get into protected mode etc.
Protected mode will be part of the boot sequence.
then you sta...
How dangerous is it to access an array out of bounds?
...user privileges, a malfunctioning program can consume excessive resources (CPU, memory, disk), possibly bringing down the entire system. A lot of malware (viruses, etc.) exploits buffer overruns to gain unauthorized access to the system.
(One historical example: I've heard that on some old systems ...
Check synchronously if file/directory exists in Node.js
...nchronous calls. Calls into the I/O subsystem take significant time from a CPU's point of view. Note how easy it is to call lstat rather than lstatSync:
// Is it a directory?
lstat('/the/path', function(err, stats) {
if (!err && stats.isDirectory()) {
// Yes it is
}
});
Bu...
Under what circumstances are linked lists useful?
...retty fast, because the array is filled sequentially (plays very nice with CPU cache).
Not to mention that a chaining hash table is expensive in terms of memory - and this "trick" cuts "pointer sizes" in half on x64.
Essentially, many linked lists are stored in an array. (one for each bucket used...
Why Large Object Heap and why do we care?
...sn't just make memory usage more efficient (no unused holes), it makes the CPU cache much more efficient. The cache is a really big deal on modern processors, they are an easy order of magnitude faster than the memory bus.
Compacting is done simply by copying bytes. That however takes time. The ...
Simulating tremor (from e.g. Parkinson's Disease) with the mouse on a webpage?
...ou might want to replace the colon by something like "sleep 0.01" to limit cpu usage and speed, because on my rig it makes unrealistic fast jumps with your code.
– nonchip
Aug 13 '14 at 17:11
...
String, StringBuffer, and StringBuilder
...nce from a String may carry an unacceptable performance penalty, either in CPU time or memory (obtaining substrings is CPU efficient because the data is not copied, but this means a potentially much larger amount of data may remain allocated).
You use StringBuilder when you need to create a mutable ...
[精华] VC中BSTR、Char和CString类型的转换 - C/C++ - 清泛网 - 专注C/C++及内核技术
...配和释放。
5.下面介绍一种比较复杂的情况,利于对问题的深入理解。例如我们现在用到的ICF底层库就有很多类似下面的函数:
void CTestDlg::GetString(BSTR* state)
{
_bstr_t m_state(L"cc");
*state = m_state.copy();
}
其中_bstr_...
Scheduling recurring task in Android
...accept best answer if I am wrong .
Alarm Manager
The Alarm Manager holds a CPU wake lock as long as the alarm receiver's onReceive() method is executing. This guarantees that the phone will not sleep until you have finished handling the broadcast. Once onReceive() returns, the Alarm Manager releases...