装配体和浮点数 [英] Assembly divisions and floating points

问题描述

  mov eax, 0x01
  mov ecx, 0x02
  div ecx                 ; Divide AX/CX, saves remainder in DX
  cmp dx, 0
  je OddNumber
  int 80h

当我尝试除以1/2而不是将其标记为OddNumber时，它将返回浮点异常".我知道1/2是浮点数，但是我该如何处理呢?谢谢.

When I try to divide 1/2, instead of going to label OddNumber, it returns "Floating point exception". I know 1/2 is a float, but how can I handle it? Thanks.

GDB说:程序收到信号SIGFPE，算术异常."顺便说一句.

GDB says "Program received signal SIGFPE, Arithmetic exception." by the way.

推荐答案

1. 在调用div ecx之前，您需要将edx设置为零.当使用32位除数(例如ecx)时，div将edx:eax中的64位值除以其参数，因此，如果edx中存在垃圾，它将被视为股息的一部分.

1. You need to zero edx before calling div ecx. When using a 32-bit divisor (e.g, ecx), div divides the 64-bit value in edx:eax by its argument, so if there's junk in edx, it's being treated as part of the dividend.

在div之后，您可能想比较edx，而不仅仅是dx.

After the div, you probably want to compare edx, not just dx.

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