search for: lba_offset

...alues or just do some dummy computation for EBIOS */ So it's just for simplicity or lazyness. As the code doesn't do any harm (supposedly) in that case the coder just lets it run. > > - I assume that > movw $0x7c00, %bx > movw $4, %cx /* Sector count */ > movl (lba_offset), %eax > 2: > call read_sector > ... > loopw 2b > shall load the bytes of isolinux.bin to address 0x7c00. Yes, I think so. It loads the next bootloader (which is four secors instead of the usual one) to 0x7c00. It's most likely is isolinux as it has confi...

Thomas Schmitt wrote: > I ponder whether it would be possible to create a diagnostic MBR > which does not necessarily have to boot but rather tells what the > isohybrid MBR would perceive: Presence of partition table, > EBIOS or CBIOS, block address used with INT 13, content of the block > read by the first INT 13, ... ... > The diagnostic MBR should only use 432 bytes because at

...g */ /* Save sectors/cylinder on the stack */ pushw %dx /* -22: High word */ pushw %ax /* -24: Low word */ /* * Load sectors. We do this one at a time mostly to avoid * pitfalls and to share code with the stock MBR code. */ movw $0x7c00, %bx movw $4, %cx /* Sector count */ movl (lba_offset), %eax 2: call read_sector jc disk_error incl %eax addb $(512 >> 8), %bh loopw 2b /* Dump out the bytes of the first sector. */ pusha mov $0x7c00, %di mov $16, %dx 2: mov $16, %cx 1: mov (%di), %al inc %di call print_al loop 1b call print_string .ascii "\r\n"...

...ring: + pop %si + push %bp + push %ax + push %bx 2: lodsb movb $0x0e, %ah @@ -284,10 +329,11 @@ error: cmpb $10, %al /* Newline? */ jne 2b - int $0x18 /* Boot failure */ -die: - hlt - jmp die - + pop %bx + pop %ax + pop %bp + push %si + ret + /* Address of pointer to isolinux.bin */ lba_offset = _start+432 diff --git a/mbr/isohdppv.S b/mbr/isohdppv.S new file mode 100644 index 0000000..08f3881 --- /dev/null +++ b/mbr/isohdppv.S @@ -0,0 +1,3 @@ +#define DEBUG_PRINT 1 +#include "isohdppx.S" +