similar to: [PATCH 1/1] Add Diagnostic MBR for trouble-shooting

--- mbr/Makefile | 6 +- mbr/mbr-diag.S | 377 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 382 insertions(+), 1 deletions(-) create mode 100644 mbr/mbr-diag.S diff --git a/mbr/Makefile b/mbr/Makefile index 0bdf7e3..b9d743d 100644 --- a/mbr/Makefile +++ b/mbr/Makefile @@ -17,7 +17,7 @@ topdir = .. include $(topdir)/MCONFIG.embedded -all: mbr.bin gptmbr.bin

--- mbr/Makefile | 6 +- mbr/mbr-diag.S | 372 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 377 insertions(+), 1 deletions(-) create mode 100644 mbr/mbr-diag.S diff --git a/mbr/Makefile b/mbr/Makefile index 0bdf7e3..b9d743d 100644 --- a/mbr/Makefile +++ b/mbr/Makefile @@ -17,7 +17,7 @@ topdir = .. include $(topdir)/MCONFIG.embedded -all: mbr.bin gptmbr.bin

Thomas Schmitt wrote: > My main point of interest is which block is really loaded as first one > of isolinux.bin. [Program snipped.] > (It could be shorter if i did not insist in big endian words.) Why insisting? Anyway appended is a dumper version. I could put up a binery version if needed. Let me know if so. -- MartinS /*

If EBIOS is detected for this drive it tries to read sector size and use it. If error or no EBIOS 512 is assumed. Buffer to read sector size if always allocated into the stack. CHS informations are not readed as not needed and same space not restoring %dl for drive number. Signed-off-by: Frediano Ziglio <frediano.ziglio at citrix.com> --- mbr/gptmbr.S | 42

git://git.zytor.com/users/genec/syslinux.git Branch handoff-mbr-for-hpa This is a piece of code that can be used in place of a MBR or VBR/PBR (master boot record; volume/partition) in order to examine the data handed to the respective boot code. AX, SS, and SP are destroyed before examining anything. I set an internal restriction that limits it to 420 bytes such that it could be used with a

Thomas Schmitt said: > I am wondering about the meaning or reason of "+20" in this assembler line: > > movl (32+20)(%si), %ecx > > Why that extra offset 20 on the byte offset 32 which is specified by > GPT specs (UEFI 2.4, 5.3.3) ? (Do i get the language wrong ?) Well I've been looking at this. It seems gptmbr.S

--- mbr/isohdpfx.S | 10 ++++++++++ 1 files changed, 10 insertions(+), 0 deletions(-) diff --git a/mbr/isohdpfx.S b/mbr/isohdpfx.S index 9e9d55c..bddb533 100644 --- a/mbr/isohdpfx.S +++ b/mbr/isohdpfx.S @@ -67,6 +67,7 @@ _start: movw %ax, %ss movw $stack, %sp movw %sp, %si + movw %sp, %bp /* needed later if drive number is to be forced due to Ctrl key being pressed */ pushw %es /*

From: MartinS <ams at ludd.ltu.se> isohdp[fp]v.S which says E or C if EBIOS or CBIOS is used. isohdppv.S also says G or M if a GPT or MBR partition is detected. Signed-off-by: MartinS <ams at ludd.ltu.se> --- Comments? diff --git a/mbr/Makefile b/mbr/Makefile index be2bded..7095396 100644 --- a/mbr/Makefile +++ b/mbr/Makefile @@ -21,7 +21,8 @@ include $(MAKEDIR)/embedded.mk all:

On Fri, Mar 24, 2017 at 2:55 PM, Martin Str|mberg via Syslinux <syslinux at zytor.com> wrote: > On Fri, Mar 24, 2017 at 05:38:31PM +0100, Thomas Schmitt via Syslinux wrote: >> isohdpfc pushes the CX value to the stack which it gets from INT 13 AH 41. >> Quite surely bit 0 of that CX is not set. But bit 2 "Enhanced Disk Drive" >> could be set. >>

On Sat, Mar 25, 2017 at 06:51:50PM +0100, Geert Stappers via Syslinux wrote: > It is good to see this > ----- Forwarded message from syslinux-bot for Martin Str|mberg <ams at ludd.ltu.se> ----- > Date: Sat, 25 Mar 2017 05:54:09 -0700 > From: syslinux-bot for Martin Str|mberg <ams at ludd.ltu.se> > Subject: [syslinux:master] mbr/isohdpfx.S: correct pointer for

On Fri, Mar 24, 2017 at 05:38:31PM +0100, Thomas Schmitt via Syslinux wrote: > isohdpfc pushes the CX value to the stack which it gets from INT 13 AH 41. > Quite surely bit 0 of that CX is not set. But bit 2 "Enhanced Disk Drive" > could be set. > https://en.wikipedia.org/wiki/INT_13H > > I understand on David's BIOS after > > andw $1,%cx

Op 2013-12-15 om 17:39 schreef Ferenc Wagner: > Ruben Kerkhof <ruben at rubenkerkhof.com> writes: > > > /* 80 00 00 00 ee 00 00 00 > > - - bootable partition, type EFI (EE), no CHS information */ > > + - bootable partition, type EFI (ED), no CHS information */ > > Please fix the previous comment line as well. As I understand that, so in _my words_:

> Op 2013-12-15 om 17:39 schreef Ferenc Wagner: > > Ruben Kerkhof <ruben at rubenkerkhof.com> writes: > > > > > /* 80 00 00 00 ee 00 00 00 > > > - - bootable partition, type EFI (EE), no CHS information */ > > > + - bootable partition, type EFI (ED), no CHS information */ > > > > Please fix the previous comment line as well.

This patches add support for dynamic sectors to GPT MBR code. First 3 patches are trick and optimizations to gain some space for the forth patch. I have a modified version of SeaBIOS, some code and some script o test it I'll send on a different mail.

Hi, i am looking now at the code which i assume loads the rest of isolinux.bin. The entry point for program execution from the MBR is obviously at http://git.zytor.com/syslinux/syslinux.git/tree/core/isolinux.asm#n186 (Do i get it right that this is the Intel syntax ? (Gronfff)) If POP yields the victim of the most recent not yet popped PUSH, then this does not look correctly coordinated

Found some stray descriptor table accessors that had non-optimal assembler constraints. Use "q" to get word, high and low byte access without forcing a specific register constraint. Add desc as a memory output operand. Also, get_base was completely unused. Deprecate it. The function get_limit is also unused, but I did not deprecate it; it could be used in arch/i386/mm/fault.c.

Found some stray descriptor table accessors that had non-optimal assembler constraints. Use "q" to get word, high and low byte access without forcing a specific register constraint. Add desc as a memory output operand. Also, get_base was completely unused. Deprecate it. The function get_limit is also unused, but I did not deprecate it; it could be used in arch/i386/mm/fault.c.

The handover protocol uses ED as partition type but the comment above it still mentions EE Signed-off-by: Ruben Kerkhof <ruben at rubenkerkhof.com> --- mbr/gptmbr.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mbr/gptmbr.S b/mbr/gptmbr.S index 7f450d3..8ab6b50 100644 --- a/mbr/gptmbr.S +++ b/mbr/gptmbr.S @@ -194,7 +194,7 @@ found_part: pushw %di /* 80 00 00 00

Use an early clobber on addr to avoid the extra rorl instruction at the end of _set_tssldt_desc. Also, get some C type checking on the descriptor struct here. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.13/include/asm-i386/desc.h =================================================================== --- linux-2.6.13.orig/include/asm-i386/desc.h 2005-08-08

Move base / limit accessors into desc.h, where they properly belong. Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.13/include/asm-i386/system.h =================================================================== --- linux-2.6.13.orig/include/asm-i386/system.h 2005-08-08 17:58:03.000000000 -0700 +++ linux-2.6.13/include/asm-i386/system.h 2005-08-08 18:01:31.000000000 -0700