Tandy 1000 Programmer's Reference Manual page 105

Chapter 1 I System Calls
MkDir
Create Subdirectory Function Call 39H
Creates a new directory entry at the end of a specified
pathname.
Entry Conditions:
AH
=
39H
DSDX
=
pointer to
ASCIIZ
pathname
Exit Conditions:
Carry set:
AX
=
error code
Carry not set:
No error.
Error Returns:
AX
=
3
Path not found. The path specified was invalid or not
found.
Access denied. The directory could not be created (no
room in the parent directory), the directory/file al-
ready existed, or a device name was specified.
AX
=
5
Example:
M k D i r
eq" 39H
I d 5
dx,pathname
mov a h , M k D i r
i n t
21
H
103