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─────Run-Time Library───────────────────────────────────────────────────────
 
     The _bdos function invokes the DOS system call specified by
     <dosfunc> after placing the values specified by <dosdx> and
     <dosal> in the DX and AL registers, respectively. The _bdos
     function executes an INT 21H instruction to invoke the system
     call. When the system call is complete, _bdos returns the contents
     of the AX register.
 
     The _bdos function is intended to be used to invoke DOS system
     calls that either take no arguments or take only arguments in the
     DX (DH, DL) and/or AL registers.
 
     Do not use the _bdos function to call interrupts that modify the
     DS register. Instead, use the _intdosx or _int86x function. The
     _intdosx and _int86x functions load the DS and ES registers from
     the <segregs> argument and store these registers in <segregs>
     after the function call.
 
     This call should not be used to invoke system calls that indicate
     errors by setting the carry flag. Since C programs do not have
     access to this flag, the status of the return value cannot be
     determined. The _intdos function should be used in these cases.
 
     Return Value
 
     The _bdos function returns the value of the AX register after the
     system call has completed.
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