masm开发中@@.@F,@B

最新推荐文章于 2022-10-18 17:46:48 发布

原创最新推荐文章于 2022-10-18 17:46:48 发布 · 973 阅读

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本文介绍了一种用于定义局部代码标签的语法，这种标签可用于条件和无条件跳转指令中，以便于实现对附近代码段的跳转。通过实例展示了如何使用这种标签来简化循环和条件判断的编写。

Local Code Labels

  Syntax:   [instruction] @F
                .
                .
                .
            @@: [statement]
                .
                .
                .
                [instruction] @B

  Description:

     The @@: label defines a local code label, which is in effect until
     the next instance of @@:. The @F and @B operands can be used in
     conditional and unconditional jump statements to jump to the next

     and previous @@: label respectively.

     The @@: label is useful for defining a nearby jump point where a
     full label is not appropriate.

  Example:

           cmp     ax, 18h
           jg      @F
           -                  ;Less than or equal
           -
           -
     @@:                      ;Greater than

           mov     cx, 640    ;Set count

     @@:
           -                  ;Loop statements
           -
           -

           loop    @B         ;Loop back