If an application maps expanded memory at addresses below 640 KB, the application must trap all possible conditions that might lead to a warm boot, so that this function can be called first.Prepares the expanded memory hardware for an impending warm boot. This function affects the current mapping context, the alternate register set in use, and any other expanded memory hardware dependencies that would ordinarily be initialized at system boot time.
Call with:
AH = 5CH
Returns:
If function successful
AH = 00H
If function unsuccessful
AH = error code
Note:
If an application maps expanded memory at addresses below 640 KB, the application must trap all possible conditions that might lead to a warm boot, so that this function can be called first.