- Function
Make a page of extended memory accessible.
- Header
- Declaration
void* __fastcall__ em_map (unsigned page);
- Description
The function maps one page of extended memory into linear memory and returns a pointer to the page frame. Depending on the hardware and driver, the data is either mapped into the address space or transfered into a buffer. If you don't need the actual contents of the page (for example because you're going to overwrite it completely, it is better to call
em_use
instead.em_use
will not transfer the data if it is possible to avoid that.- Limits
- Calling
em_map
will invalidate the memory window, so if you made any changes to the data in the window, callem_commit
first, or the changes are lost.- The function is only available as fastcall function, so it may only be used in presence of a prototype.
- The function produces undefined results if no extended memory driver is loaded.
- Availability
cc65
- See also
- Example
None.