Function 4B03h Load Overlay

mov dx, seg ProgName

mov ds, dx

mov dx, offset ProgName ;ds:dx points to program name

mov bx, seg OvlArgs

mov es, bx

mov bx, offset OvlArgs ;es:bx points to LOADOVERLAY structure

mov ax, 4B03h ;Load Overlay

int 21h

jc error_handler ;carry set means error

Load Overlay (Function 4B03h) loads a program as an overlay. MS-DOS loads the overlay into memory already allocated by the program.

Parameters

ProgName

Points to a zero-terminated ASCII string that specifies the program to load. The program name must be a valid MS-DOS filename.

OvlArgs

Points to a LOADOVERLAY structure that contains information used to load overlays. The LOADOVERLAY structure has the following form:

LOADOVERLAY STRUC

loStartSegment dw ? ;segment address of overlay's memory

loRelocationFactor dw ? ;relocation factor

LOADOVERLAY ENDS

For a full description of the LOADOVERLAY structure, see Chapter 5, “Program Management.”

Return Value

If the function is successful, the carry flag is clear. Otherwise, the carry flag is set and the AX register contains an error value, which may be one of the following:

Value

Name

0001h	ERROR_INVALID_FUNCTION
0002h	ERROR_FILE_NOT_FOUND
0003h	ERROR_PATH_NOT_FOUND
0004h	ERROR_TOO_MANY_OPEN_FILES
0005h	ERROR_ACCESS_DENIED
0008h	ERROR_NOT_ENOUGH_MEMORY
000Ah	ERROR_BAD_ENVIRONMENT