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Diffstat (limited to 'sys/arch')
| -rw-r--r-- | sys/arch/i386/stand/README | 151 |
1 files changed, 0 insertions, 151 deletions
diff --git a/sys/arch/i386/stand/README b/sys/arch/i386/stand/README deleted file mode 100644 index 9803dbc1030..00000000000 --- a/sys/arch/i386/stand/README +++ /dev/null @@ -1,151 +0,0 @@ -$OpenBSD: README,v 1.13 2003/11/08 19:17:28 jmc Exp $ - -# hmm, no copyright - -Ok, just a couple quick pointers to people hacking on this stuff. These -are things that I have found out, and hopefully will make things easier -for the next dude. - -First of all, don't trust gas to get the opcodes right. Look at the -listing (-Wa,a), and check them. In particular, check for EIP relative -and absolute addressing. Some of this stuff is pretty hairy in that way. - -Debugging this stuff is hell. Remember that stores directly to video -memory will go a long way towards tracking how far things are getting, -especially when you don't have the BIOS handy. (movl %0x07410741, 0xb8000) - - -The basics of the /boot system is the following: - -biosboot: 512 bytes of the first sector on the disk/partition. This loads -/boot (or whatever you did with installboot) into ram. - -boot: starts protected mode, and process simple command line. -There is some magic here in terms of the placement and size of the various -segments, as this piece of code has to switch between real and protected -mode many times to load the next piece of the puzzle, /bsd.gz. - -bsd: The kernel itself, can be gzipped if ya want. - - -The basic steps at creating a boot floppy for yourself, and checking things -out are the following: - -1.) Compile a kernel you wish to use. -2.) Compile the new stand stuff. -3.) Mount floppy. -4.) Copy boot and kernel to floppy. (Kernel could be gzipped if needed) -5.) Run installboot on floppy. -6.) Unmount floppy. -7.) Test... - -A quick pasto for ya: -> natasha# mount /dev/fd0a /mnt -> natasha# cp boot/obj/boot /mnt -> natasha# gzip -9c bsd > /mnt/bsd.gz -> natasha# installboot -v /mnt/boot biosboot /dev/rfd0a -> boot: /mnt/boot -> proto: biosboot/obj/biosboot -> device: /dev/rfd0a -> -> biosboot/obj/biosboot: entry point 0 -> proto bootblock size 512 -> room for 32 filesystem blocks at 0x138 -> Will load 9 blocks of size 4096 each. -> 0: 4 @(2 1 15) (104-107) -> 1: 18 @(3 0 1) (108-125) -> 2: 18 @(3 1 1) (126-143) -> 3: 18 @(4 0 1) (144-161) -> 4: 14 @(4 1 1) (162-175) -> /mnt/boot: 5 entries total -> natasha# umount /mnt -> natasha# - - -Sun Apr 6 20:16:55 CDT 1997 ----------------------------- - -Ok, from general comments on icb leads me to believe this stuff has a ways -to go. First of all, there are a lot of debug frobs to video memory at -0xb8000 when DEBUG* is defined. Also, if you boot a kernel, and find that -you get a scrolling screen, press pause to get it to stop. You should then -be able to read the register dump. - -Note, currently gzipped kernel do not work. Do not know the reason, we are -working on resolving that. - - -Fri Apr 11 14:18:41 CDT 1997 ----------------------------- - -Ok, yeah, the .gz kernel gets to the probe (and then cacks later due to -no swap). Things should start working nicer from now on. The problem -was with -DSAVE_MEMORY, I believe that the stuff in libsa/cread.c was -not (and still is not with the define) being done right. I suspect -the inflateInit2(), which had a parameter changed from -15 to -11. -The problem manifested itself by loading a corrupted kernel. On the -other hand, it checksummed ok though, so there might be a small bug in -the libz stuff. Also, I don't understand libz, but I do know that -things work without -DSAVE_MEMORY, and don't with it defined. - - -Mon Apr 21 15:25:42 EDT 1997 ----------------------------- - -Now memory limits are not a concern. No more restrictions on placement -and size of code/data. It would be an idea to move PMMM code from kernel -into /boot to use low memory somehow. Also remember that the upper 64k is -used by apm, so do not grow heap too much... Low 64k is used for real mode -IDT, BIOS data, stack for /boot, so stack is big enough (about 60k). -All the magic w/ prot-real mode interface now in one place <libsa/gidt.S>. -BIOS (and DOS soon) interrupt entry points are now just as simple as -they are in real mode (just use a macro BIOSINT, which shifts int number -by 0x20, that all! ;). - - -Sat May 31 12:06:37 EDT 1997 ----------------------------- - -usleep(int15,f86) BIOS call is not supported well in all the BIOSes, -especially some laptop BIOSes and Compaq machines. Everybody is encouraged -to use sleep instead, it's known to work. - - -Thu Jul 17 21:24:42 EDT 1997 ----------------------------- - -Return to the way when code has to be less than 64k, or better say that -whole gidt.S code must be in the 1st 64k of /boot .text section. -This saves about 2k of code (idt initialization). -APM information is now gathered and passed to the locore.s upon kernel -startup as a pointer to the struct apm_connect_info. - - -Wed Aug 27 16:30:51 EDT 1997 ----------------------------- - -BIOS boot device number is passed to the kernel along with BIOS geometry -for that drive and other info. APM connect info is passed as well not in -that apm0 structure, so apm0 will become a slave on bios0 soon. -To get your /boot installed properly on a hardrive you have to load /bsd -from that hd/partition (since only boot drive geometry is passed). - - -Mon Oct 13 16:41:18 CDT 1997 ----------------------------- - -Clean up memprobe some, adding support for querying the BIOS for the -memory map. Resort to the old invasive probe if all else fails. Add -preliminary support for passing a memory map to the kernel, instead of -cnvmem/extmem. This should make weird boards easier to support in the -future. - - -Tue Jan 6 19:51:43 CST 1998 ----------------------------- - -Query and pass PCI BIOS information to the kernel. This should help in -determening the correct configuration mode to use. Pass in cnvmem/extmem -as the user sets the amount of memory with the 'set memory' command, or -the amount calculated by the memory find/probe routines. - |