Hello, LEDs (was RE: Meta Boot Loader)

Tue May 2 17:42:40 EDT 2000

Again, I'm following up on my own post...

It's not pretty, but I am now able to download and run code
without using the VxWorks tools.  I took a stab at parsing
the vxWorks file (see below) and got far enough to create a
file with my "Hello, LEDs" code:

(Offset)   (Bytes)                  (Comments)
00000000:  00 0A                    Magic Number = 0A00
00000002:  03 00                    ??? = 0003
00000004:  00 00 00 00
00000008:  00 00 00 00              Next Section File Offset
0000000C:  BE 23 00 00              ??? = 23BE
00000010:  1C 00 07 A1              ??? = A107001C
00000014:  0B 01 00 00              ??? = 0000010B
00000018:  24 00 00 00              .text length
0000001C:  00 00 00 00              .data length
00000020:  00 00 00 00              .bss  length
00000024:  00 10 00 00 00 10 00 00  .text memory start (twice)
0000002C:  24 00 00 00              .data memory start

00000030:  2E 74 65 78 74 00 00 00  ".text"
00000038:  00 10 00 00 00 10 00 00  Memory Start = 00001000
00000040:  24 00 00 00              Length       = 00000024
00000044:  A8 00 00 00              File Offset  = 000000A8
00000048:  00 00 00 00 00 00 00 00
00000050:  00 00 00 00 20 00 00 00  ??? text section indicator

00000058:  2E 64 61 74 61 00 00 00  ".data"
00000060:  24 10 00 00 24 10 00 00  Memory Start = 00001024
00000068:  00 00 00 00              Length       = 00000000
0000006C:  00 00 00 00              File Offset  = 00000000
00000070:  00 00 00 00 00 00 00 00
00000078:  00 00 00 00 40 00 00 00  ??? data section indicator

00000080:  2E 62 73 73 00 00 00 00  ".bss"
00000088:  24 10 00 00 24 10 00 00  Memory Start = 00001024
00000090:  00 00 00 00              Length       = 00000000
00000094:  00 00 00 00
00000098:  00 00 00 00 00 00 00 00
000000A0:  00 00 00 00 80 00 00 00  ??? bss section indicator

000000A8:  0D C0 A0 E1 00 D8 2D E9  The text section (my code)
000000B0:  04 B0 4C E2 E1 35 A0 E3  
000000B8:  42 39 83 E2 03 20 A0 E3
000000C0:  00 20 83 E5 FE FF FF EA
000000C8:  00 A8 5B E9

The VxWorks loader will accept this 204 byte file and it
does display a "3" on one of the LED displays.  If anyone
has real documentation on the file format, please let me
know.

-Scott

Scott C. Karlin writes:
> 
> Johnson, Erik J writes:
> > 
> > Scott C. Karlin writes:
> > >
> > >    I'm using the default start address of 0x00008000.
> > 
> > Just watching the vxWorks link step, I see that they place
> > the text segment at 0x1000, that is probably the first thing
> > I would try.  You can also type make vxWorks in the
> > BoardSupport\VxWorks\IXP1200EB directory and watch for other
> > compiler/linker options being passed into the process of
> > making vxWorks.  It looks like they change the entry point
> > to sysInit, but I can't imagine the actual name of the entry
> > point is important.
> >
> > I also wonder if the boot loader assumes anytype of compression
> > and/or checksums.  I thought there was a checksum in the a.out
> > header (?) and I don't think the vxWorks image I have is
> > compressed (I can look at its symbols...)
> 
> I agree, the first bytes of the vxWorks file from the CDROM are:
> 
> 00000000:  00 0A 03 00 00 00 00 00 9C 64 09 00 BE 23 00 00  .........d...#..
> 00000010:  1C 00 07 A1 0B 01 00 00 18 31 09 00 DC 32 00 00  .........1...2..
> 00000020:  08 B1 00 00 00 10 00 00 00 10 00 00 18 41 09 00  .............A..
> 00000030:  2E 74 65 78 74 00 00 00 00 10 00 00 00 10 00 00  .text...........
> 00000040:  18 31 09 00 A8 00 00 00 00 00 00 00 00 00 00 00  .1..............
> 00000050:  00 00 00 00 20 00 00 00 2E 64 61 74 61 00 00 00  .... ....data...
> 00000060:  18 41 09 00 18 41 09 00 DC 32 00 00 C0 31 09 00  .A...A...2...1..
> 00000070:  00 00 00 00 00 00 00 00 00 00 00 00 40 00 00 00  ............ at ...
> 00000080:  2E 62 73 73 00 00 00 00 F4 73 09 00 F4 73 09 00  .bss.....s...s..
> 00000090:  08 B1 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> 000000A0:  00 00 00 00 80 00 00 00 00 10 0F E1 3F 10 C1 E3  ............?...
> 000000B0:  D3 10 81 E3 01 F0 29 E1 4C 11 9F E5 02 20 A0 E3  ......).L.... ..
> 000000C0:  00 20 81 E5 9C 1F A0 E3 01 10 81 E3 80 1F 81 E3  . ..............
> 000000D0:  10 1F 01 EE 00 10 A0 E3 10 1F 0D EE 11 20 A0 E3  ............. ..
> 000000E0:  18 11 9F E5 00 20 81 E5 51 EF 0F EE 00 10 A0 E3  ..... ..Q.......
> 000000F0:  13 1F 0E EE 18 1F 0E EE 9A 1F 07 EE 16 1F 07 EE  ................
> 
> This is neither a.out nor binary.  It also isn't compressed.
> 
> -Scott
> 