this is first line in x86 intel firmware which is presumably executed at 0xFFFFFFF0. I believe it is a jump to more bios/firmware and is standard to jump because there is only 16 bytes more to use at the current instruction pointer (I forget the allowed size for a segment in real mode but the bios shadow area just below 4 Gbytes and this is near the top, so it shouldn't be able to access beyond 0xFFFFFFFF thus 16 bytes more maybe someone can clarify). start   jmp     <$40Sorry I do not know assembly, yet... What location is <$40 or points to?second questionI read in intel atom data sheets that in the DOS region in real mode just after reset, (0-1Mbyte) there are two 64 kbyte EPROM regions which I don't quite understand. Are these MMIO mapped to the 2 allowable flash devices? If so it says the maximum size is 16 Mbytes each yet these are 64 kbyte regions. It makes sense that in real mode it can only address 1 Mbyte so maybe only the bios regions are mapped there, but how can I determine a 1 to 1 mapping in non descriptor mode (intel doesn't make public how to fill out the trusted execution engine section and even the flash descriptor in general I can only find old documents not specific to Intel Atom)?third question What about the upper memory region at 4Gbytes, this is just shadowed dram, but if the DOS EPROM regions are maybe dram too, anyways it seems there are two similar or maybe same regions one in DOS below 1Mbyte and one at top just below 4Gbyte. If anyone can help me on any of these questions I would appreciate it, thanks.
x86 Intel atom firmware/bootstrap code
x86;firmware;bios