ZC: Delphi7 中的报错信息为（主要信息）："Invalid floating point operation"
1、http://bbs.csdn.net/topics/391070674 （LongWord($133f)这句是什么意思-CSDN论坛.html）
2楼：
这个应该用_control87或者_controlfp
#include <float.h>
_control87(0x133f, 0xffff);
至于LongWord($133f)这是没有什么意义的，LongWord($133f)=$0000133f，32位无符号整数，仅此而已。
4楼：
// Default value (with exceptions) is 0x1372.这个注释是错的，默认值是0x1332。
Set8087CW是Delphi RTL函数，C++中最好还是用_control87或者_controlfp。
2、官方资料：
2.1、Set8087CW (C++) - RAD Studio Code Examples.html （http://docwiki.embarcadero.com/CodeExamples/XE8/en/Set8087CW_%28C%2B%2B%29）
Description
This example accesses the Floating Point Unit (FPU) control register. Try turning floating point exceptions off and on and dividing a number by zero to test it.
Code
Word Saved8087CW;
void __fastcall TForm1::Button1Click(TObject *Sender)
{
Edit3->Text = FloatToStr(StrToFloat(Edit1->Text) / StrToFloat(Edit2->Text));
}
void __fastcall TForm1::RadioGroup1Click(TObject *Sender)
{
if (RadioGroup1->Items->Strings[RadioGroup1->ItemIndex] == "FPU Exceptions")
System::Set8087CW(Saved8087CW);
if (RadioGroup1->Items->Strings[RadioGroup1->ItemIndex] == "No FPU Exceptions")
System::Set8087CW(0x133f); // Disable all fpu exceptions.
}
__fastcall TForm1::TForm1(TComponent* Owner)
: TForm(Owner)
{
RadioGroup1->Items->Add("No FPU Exceptions");
RadioGroup1->Items->Add("FPU Exceptions");
RadioGroup1->ItemIndex = 2;
Saved8087CW = Default8087CW; // Save this, because Set8087CW changes it.
}
void __fastcall TForm1::FormDestroy(TObject *Sender)
{
System::Set8087CW(Saved8087CW); // Default value (with exceptions) is 0x1372.
}
Uses
- System.Set8087CW ( fr | de | ja )
- System.Default8087CW ( fr | de | ja )
See Also
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