README.ipl revision 1.1.6.2
1 1.1.6.2 yamt # $NetBSD: README.ipl,v 1.1.6.2 2014/05/22 11:39:51 yamt Exp $ 2 1.1.6.2 yamt 3 1.1.6.2 yamt Coding note: 4 1.1.6.2 yamt 5 1.1.6.2 yamt In order to make this relocatable, you must follow following 6 1.1.6.2 yamt restrictions: 7 1.1.6.2 yamt 8 1.1.6.2 yamt 1. Do not place any objects in text segment 9 1.1.6.2 yamt 1.1. For compiler, 10 1.1.6.2 yamt (1) do not declare or define any objects to be placed in 11 1.1.6.2 yamt text segment, that is, do not use ``const'' keyword 12 1.1.6.2 yamt (but declaring a pointer to const is probably OK), 13 1.1.6.2 yamt 14 1.1.6.2 yamt (2) make sure string literals, if any, are placed in data 15 1.1.6.2 yamt segment (use traditional compiler), 16 1.1.6.2 yamt 17 1.1.6.2 yamt (3) avoid initialization of automatic objects (non-static 18 1.1.6.2 yamt function-local variables) of aggregate types (arrays, 19 1.1.6.2 yamt structs and unions), which may implicitly emits 20 1.1.6.2 yamt constant data. 21 1.1.6.2 yamt 22 1.1.6.2 yamt In summary, do not use ANSI extension. Use traditional C. :-) 23 1.1.6.2 yamt 24 1.1.6.2 yamt 1.2. For linker, do not actually place objects in text segment. 25 1.1.6.2 yamt 26 1.1.6.2 yamt 2. Do not use function pointers. 27 1.1.6.2 yamt 28 1.1.6.2 yamt 29 1.1.6.2 yamt On-disk layout: 30 1.1.6.2 yamt 31 1.1.6.2 yamt We have 6.5KB for the primary boot. 32 1.1.6.2 yamt 33 1.1.6.2 yamt disk address 34 1.1.6.2 yamt start size 35 1.1.6.2 yamt 000000 0000FC LIF header 36 1.1.6.2 yamt 0000FC 000104 unused 37 1.1.6.2 yamt 000200 000194 disklabel (404 bytes for 16-partition label) 38 1.1.6.2 yamt 000394 00006C unused 39 1.1.6.2 yamt 000400 000400 ipl part 2 (1KB) 40 1.1.6.2 yamt 000800 000100 optional LIF directory 41 1.1.6.2 yamt 000900 000100 unused 42 1.1.6.2 yamt 000A00 000600 ipl part 3 (1.5KB) 43 1.1.6.2 yamt 001000 001000 ipl part 1 (4KB) 44 1.1.6.2 yamt 002000 (file system starts here) 45 1.1.6.2 yamt 46 1.1.6.2 yamt 47 1.1.6.2 yamt On-memory layout on IPL startup: 48 1.1.6.2 yamt 49 1.1.6.2 yamt The firmware loads ipl part 1 on the memory, and executes it. 50 1.1.6.2 yamt 51 1.1.6.2 yamt address offset 52 1.1.6.2 yamt start size 53 1.1.6.2 yamt 000000 001000 ipl part 1 54 1.1.6.2 yamt 001000 000A00 (not loaded yet) 55 1.1.6.2 yamt (bss section etc) 56 1.1.6.2 yamt x 001000 temporary disk buffer 57 1.1.6.2 yamt x+1000 stack 58 1.1.6.2 yamt 59 1.1.6.2 yamt 60 1.1.6.2 yamt Then the IPL will load the rest of itself: 61 1.1.6.2 yamt 62 1.1.6.2 yamt ipl part 1 loads parts 2 and 3, then continues execution. 63 1.1.6.2 yamt 64 1.1.6.2 yamt address offset 65 1.1.6.2 yamt start size 66 1.1.6.2 yamt 000000 001000 ipl part 1 67 1.1.6.2 yamt 001000 000400 ipl part 2 68 1.1.6.2 yamt 001400 000600 ipl part 3 69 1.1.6.2 yamt 001A00 xxxxxx (bss section etc) 70
Indexes created Fri Oct 31 11:10:07 GMT 2025