[LinuxBIOS] ram_resource question

Hello,

Can someone tell me what this memory region is reserved for?
It is 1MB to The Top Of Low Memory - 1MB right?
Is the last 1MB chipset specific or needed for the LinuxBIOS bounce buffer?

ram_resource(dev, idx++, 1024, tolmk - 1024;

Oh, this is from northbridge.c if you were wondering. I need to know  
this, because Intel IGD reserves memory from the The Top Of Physical  
Memory down.
If this is the case should I subtract the IGD memory before or after  
this function is called.

Example 1:
tolmk -= IGD_MEMORYK
ram_resource(dev, idx++, 1024, tolmk - 1024;

OR

Example 2:
ram_resource(dev, idx++, 1024, (tolmk - IGD_MEMORYK) - 1024);
ram_resource(dev, idx++, (tolmk - IGD_MEMORYK) - 1024, tolmk - IGD_MEMORYK);

Thanks - Joe