浮点操作指令

不明白 说详细点

这里有个文档，拿去看看。。基本上都有的了。。能找到你要的。。

但是我想说一句，学习最好还是要多动手，多思考。。

上传的附件：

• FPHELP.rar （45.52kb，6次下载）

Command:  FCOM QWORD PTR DS:[EDX]
Hex dump: DC12

Compares the contents of 80-bit floating-point register ST with the contents of 64-bit memory
at location [EDX] and sets FPU condition code flags:

  +----------------------+----+----+----+
  | Condition            | C3 | C2 | C0 |
  +----------------------+----+----+----+
  | ST<[EDX]             |  0 |  0 |  1 |
  +----------------------+----+----+----+
  | ST=[EDX]             |  1 |  0 |  0 |
  +----------------------+----+----+----+
  | ST>[EDX]             |  0 |  0 |  0 |
  +----------------------+----+----+----+
  | Unordered            |  1 |  1 |  1 |
  +----------------------+----+----+----+

Unordered situation occurs if either operand is NaN (Not a Number). Note that FCOM treats
positive and negative zeros as equal.

This command is frequently followed by the sequence

  FSTSW AX             ; Get FPU flags
  SAHF                 ; Store FPU flags to EFL
  Jcc label            ; Comparison-dependent action

The flags are mapped in the following way:

  +----------------------+----+----+----+
  | FPU flag             | C3 | C2 | C0 |
  +----------------------+----+----+----+
  | Mapped to CPU flag   |  Z |  P |  C |
  +----------------------+----+----+----+

至今还未研究过浮点的飘过

没有研究过····不懂得路过！