DOS Fn 6522H: Upshift ASCIIZ String

                                                         Compatibility: 3.3+ 
 Expects: AX    6522H
          DS:DX address of ASCIIZ▲ string to upshift
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 Returns: AX    error code if CF is set to CY
          DS:DX the string is converted in place
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    Info: Converts all of the characters of the ASCIIZ string starting at
          DS:DX into uppercase, using the currently-active uppercase table
          for the active country and code page.

See Also: National Language Support
          DOS Functions
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