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authorMichael Brown2008-09-24 19:33:31 +0200
committerMichael Brown2008-09-24 19:33:31 +0200
commit887d77c27ac6ccdb13892ab05e50281e63df6bbf (patch)
tree195dc9a42cd1e4eee891641b19411877aa5b0c3c /README
parent[settings] Add the uristring setting type (diff)
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[pcbios] Inhibit INT 15 memory map hiding on brain-dead BIOSes
Some really moronic BIOSes bring up the PXE stack via the UNDI loader entry point during POST, and then don't bother to unload it before overwriting the code and data segments. If this happens, we really don't want to leave INT 15 hooked, because that will cause any loaded OS to die horribly as soon as it attempts to fetch the system memory map. We use a heuristic to detect whether or not we are being loaded at the top of free base memory. If we determine that we are being loaded at some other arbitrary location in base memory, then we assume that it's not safe to hook INT 15.
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