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README.ipl revision 1.1.10.2 
      1  1.1.10.2  tls #	$NetBSD: README.ipl,v 1.1.10.2 2014/08/20 00:03:05 tls Exp $
      2  1.1.10.2  tls 
      3  1.1.10.2  tls Coding note:
      4  1.1.10.2  tls 
      5  1.1.10.2  tls 	In order to make this relocatable, you must follow following
      6  1.1.10.2  tls 	restrictions:
      7  1.1.10.2  tls 
      8  1.1.10.2  tls 	1. Do not place any objects in text segment
      9  1.1.10.2  tls 	1.1. For compiler,
     10  1.1.10.2  tls 		(1) do not declare or define any objects to be placed in
     11  1.1.10.2  tls 		    text segment, that is, do not use ``const'' keyword
     12  1.1.10.2  tls 		    (but declaring a pointer to const is probably OK),
     13  1.1.10.2  tls 
     14  1.1.10.2  tls 		(2) make sure string literals, if any, are placed in data
     15  1.1.10.2  tls 		    segment (use traditional compiler),
     16  1.1.10.2  tls 
     17  1.1.10.2  tls 		(3) avoid initialization of automatic objects (non-static
     18  1.1.10.2  tls 		    function-local variables) of aggregate types (arrays,
     19  1.1.10.2  tls 		    structs and unions), which may implicitly emits
     20  1.1.10.2  tls 		    constant data.
     21  1.1.10.2  tls 
     22  1.1.10.2  tls 	     In summary, do not use ANSI extension.  Use traditional C. :-)
     23  1.1.10.2  tls 
     24  1.1.10.2  tls 	1.2. For linker, do not actually place objects in text segment.
     25  1.1.10.2  tls 
     26  1.1.10.2  tls 	2. Do not use function pointers.
     27  1.1.10.2  tls 
     28  1.1.10.2  tls 
     29  1.1.10.2  tls On-disk layout:
     30  1.1.10.2  tls 
     31  1.1.10.2  tls 	We have 6.5KB for the primary boot.
     32  1.1.10.2  tls 
     33  1.1.10.2  tls 	disk address
     34  1.1.10.2  tls 	start	 size
     35  1.1.10.2  tls 	000000	0000FC	LIF header
     36  1.1.10.2  tls 	0000FC	000104	unused
     37  1.1.10.2  tls 	000200	000194	disklabel (404 bytes for 16-partition label)
     38  1.1.10.2  tls 	000394	00006C	unused
     39  1.1.10.2  tls 	000400	000400	ipl part 2 (1KB)
     40  1.1.10.2  tls 	000800	000100	optional LIF directory
     41  1.1.10.2  tls 	000900	000100	unused
     42  1.1.10.2  tls 	000A00	000600	ipl part 3 (1.5KB)
     43  1.1.10.2  tls 	001000	001000	ipl part 1 (4KB)
     44  1.1.10.2  tls 	002000		(file system starts here)
     45  1.1.10.2  tls 
     46  1.1.10.2  tls 
     47  1.1.10.2  tls On-memory layout on IPL startup:
     48  1.1.10.2  tls 
     49  1.1.10.2  tls 	The firmware loads ipl part 1 on the memory, and executes it.
     50  1.1.10.2  tls 
     51  1.1.10.2  tls 	address offset
     52  1.1.10.2  tls 	 start	 size
     53  1.1.10.2  tls 	000000	001000	ipl part 1
     54  1.1.10.2  tls 	001000	000A00	(not loaded yet)
     55  1.1.10.2  tls 			(bss section etc)
     56  1.1.10.2  tls 	x	001000	temporary disk buffer
     57  1.1.10.2  tls 	x+1000		stack
     58  1.1.10.2  tls 
     59  1.1.10.2  tls 
     60  1.1.10.2  tls Then the IPL will load the rest of itself:
     61  1.1.10.2  tls 
     62  1.1.10.2  tls 	ipl part 1 loads parts 2 and 3, then continues execution.
     63  1.1.10.2  tls 
     64  1.1.10.2  tls 	address offset
     65  1.1.10.2  tls 	 start	 size
     66  1.1.10.2  tls 	000000	001000	ipl part 1
     67  1.1.10.2  tls 	001000	000400	ipl part 2
     68  1.1.10.2  tls 	001400	000600	ipl part 3
     69  1.1.10.2  tls 	001A00	xxxxxx	(bss section etc)
     70