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...fx.S: correct pointer for heads/sectors sectors is pushed first then heads but pointers were in reverse order. Signed-off-by: Gene Cumm <gene.cumm at gmail.com> --- mbr/isohdpfx.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mbr/isohdpfx.S b/mbr/isohdpfx.S index 17e1efe..a693ccb 100644 --- a/mbr/isohdpfx.S +++ b/mbr/isohdpfx.S @@ -48,8 +48,8 @@ isolinux_start_hybrid = 0x7c00+64+4 stack = 0x7c00 partoffset = (stack-8) driveno = (stack-14) -heads = (stack-16) -sectors = (stack-18) +sectors = (stack-16) +heads = (stack-18) ebios_flag = (stack-20) secpercy...

...pointer for heads/sectors > Commit-ID: 48e94f4fa7b3c32cbd43b6e57c64bc933f76d059 > Gitweb: http://www.syslinux.org/commit/48e94f4fa7b3c32cbd43b6e57c64bc933f76d059 > Author: Martin Str|mberg <ams at ludd.ltu.se> ... > diff --git a/mbr/isohdpfx.S b/mbr/isohdpfx.S > index 17e1efe..a693ccb 100644 > --- a/mbr/isohdpfx.S > +++ b/mbr/isohdpfx.S > @@ -48,8 +48,8 @@ isolinux_start_hybrid = 0x7c00+64+4 > stack = 0x7c00 > partoffset = (stack-8) > driveno = (stack-14) > -heads = (stack-16) > -sectors = (stack-18) > +sectors = (stack-16) > +head...

...tors were pushed in reverse order per isolinux.asm bb519a95 reversed the order of heads/sectors on the stack Signed-off-by: Gene Cumm <gene.cumm at gmail.com> --- mbr/isohdpfx.S | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/mbr/isohdpfx.S b/mbr/isohdpfx.S index 17e1efe..f9e9691 100644 --- a/mbr/isohdpfx.S +++ b/mbr/isohdpfx.S @@ -175,12 +175,12 @@ next: /* Get (C)HS geometry */ movb $0x08, %ah int $0x13 - andw $0x3f, %cx /* Sector count */ popw %bx /* EBIOS flag */ - pushw %cx /* -16: Save sectors on the stack */ movzbw %dh, %ax /* dh = max head */...

...inux.asm it seems that previous choice was wrong and the declared offsets were correct. Thus a new patch that corrects the order of pushes (instead of offsets) _and_ setting CX to zero if EBIOS detection fails. Apply it to orginal syslinux code. diff --git a/mbr/isohdpfx.S b/mbr/isohdpfx.S index 17e1efe..14eca14 100644 --- a/mbr/isohdpfx.S +++ b/mbr/isohdpfx.S @@ -151,7 +151,7 @@ next: /* Check to see if we have EBIOS */ pushw %dx /* drive number */ - movb $0x41, %ah /* %al == 0 already */ + movb $0x41, %ah movw $0x55aa, %bx xorw %cx, %cx xorb %dh, %dh @@ -167,20 +167,22 @@ next:...

...^altmbr[^0-9a-z]/) { $maxsize = $padsize = 439; diff --git a/mbr/isohdpfv.S b/mbr/isohdpfv.S new file mode 100644 index 0000000..46c9c07 --- /dev/null +++ b/mbr/isohdpfv.S @@ -0,0 +1,3 @@ +#define DEBUG_PRINT 1 +#include "isohdpfx.S" + diff --git a/mbr/isohdpfx.S b/mbr/isohdpfx.S index 17e1efe..6d8ab36 100644 --- a/mbr/isohdpfx.S +++ b/mbr/isohdpfx.S @@ -121,10 +121,24 @@ _start: /* We have GPT partition information */ movl (32+20)(%si), %ecx movl (36+20)(%si), %ebx + +#ifdef DEBUG_PRINT + push %si + call print_string + .ascii "G\r\n" + pop %si +#endif jmp 1f /* We...

...e > was wrong and the declared offsets were correct. > > Thus a new patch that corrects the order of pushes (instead of > offsets) _and_ setting CX to zero if EBIOS detection fails. Apply it > to orginal syslinux code. > > diff --git a/mbr/isohdpfx.S b/mbr/isohdpfx.S > index 17e1efe..14eca14 100644 > --- a/mbr/isohdpfx.S > +++ b/mbr/isohdpfx.S > @@ -151,7 +151,7 @@ next: > > /* Check to see if we have EBIOS */ > pushw %dx /* drive number */ > - movb $0x41, %ah /* %al == 0 already */ > + movb $0x41, %a...

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

EFI systems typically don't support booting off ISO 9660 filesystems, even if written to USB sticks. This patch adds support for generating a GPT that covers the stick as well, with an additional partition entry pointing purely at the secondary El Torito image. When burned to CD the secondary El Torito will be used as an EFI boot image, and when written to a USB stick the GPT partition