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The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

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     Consider the following principles when you enter instruction
     mnemonics:
 
        ■ The far-return mnemonic is RETF.
 
        ■ String mnemonics must explicitly state the string size. For
          example, MOVSW must be used to move word strings, and MOVSB
          must be used to move byte strings.
 
        ■ CodeView automatically assembles short, near, or far jumps
          and calls, depending on byte displacement to the destination
          address. These may be overridden with the NEAR or FAR prefix.
          The NEAR prefix can be abbreviated to NE, but the FAR prefix
          cannot be abbreviated.
 
        ■ CodeView cannot determine whether some operands refer to a
          word memory location or to a byte memory location. In these
          cases, the data type must be explicitly stated with the
          prefix WORD PTR or BYTE PTR. Acceptable abbreviations are WO
          and BY.
 
        ■ CodeView cannot determine whether an operand refers to a
          memory location or to an immediate operand. CodeView uses the
          convention that operands enclosed in square brackets ([])
          refer to memory.
 
        ■ CodeView supports all forms of indirect register
          instructions.
 
        ■ All instruction-name synonyms are supported. If you
          assemble instructions and then examine them with the
          Unassemble (U) command, CodeView may show synonymous
          instructions, rather than the ones you have assembled.
 
        ■ Do not assemble and execute 8087/287 instructions if your
          system is not equipped with one of these math coprocessor
          chips.
 
     The effects of the Assemble command are temporary. Any
     instructions that you assemble are lost as soon as you exit
     the program.
 
     The instructions you assemble are also lost when you restart
     the program with the Restart (L) command on the Run menu. The
     original code is reloaded, possibly writing over parts of
     memory that you have changed.
     See: ◄Run Menu: Restart Command►
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