diff options
Diffstat (limited to 'bootblocks/mbr.s')
| -rw-r--r-- | bootblocks/mbr.s | 63 |
1 files changed, 62 insertions, 1 deletions
diff --git a/bootblocks/mbr.s b/bootblocks/mbr.s index ddd406f..c0fa542 100644 --- a/bootblocks/mbr.s +++ b/bootblocks/mbr.s @@ -5,10 +5,16 @@ ! In addition it has the facility to load and execute a small program ! (of 8 extents) before the boot blocks are checked. ! +! Or +! +! Space for 12 extra partitions in a form that Linux _does_ understand. +! ! Lowest available is $0500, MSDOS appears to use $0600 ... I wonder why? ORGADDR=$0500 -preboot=0 ! Include the pre-boot loader ? +preboot=0 ! Include the pre-boot loader. +diskman=1 ! Disk manager partitions, allows 16 partitions but + ! don't overwrite this with a LILO BB. ! Include standard layout org ORGADDR @@ -19,11 +25,15 @@ public partition_2 public partition_3 public partition_4 + if diskman=0 org ORGADDR+$3 .ascii "ELKS MBR Copyright 1996, Robert de Bath" ! Start after dos fsstat data, not strictly required. org codestart + else +org ORGADDR + endif cli ! Assume _nothing_! cld mov bx,#$7C00 ! Pointer to start of BB. @@ -80,6 +90,21 @@ bad_boot: cmp si,#bootblock_magic jnz check_active + # Check for Disk manager partitions (12 more!) + if diskman + cmp word ptr diskman_magic,#$55AA + jnz no_diskman + mov si,#partition_1 +check_next: + sub si,#partition_2-partition_1 + cmp byte [si],#$80 ! Flag for activated partition + jz found_active + cmp si,#low_partition + jnz check_next + +no_diskman: + endif + mov si,#no_bootpart ! Message & boot jmp no_boot @@ -154,6 +179,42 @@ pre_boot_table: .word 0 endif + if diskman + if *>ORGADDR+0xfc + fail! Disk manager partition overlap + endif + + org ORGADDR+0xFC +public diskman_magic +diskman_magic: + .word $55AA +low_partition: +public partition_16 +partition_16 = low_partition+0x00 +public partition_15 +partition_15 = low_partition+0x10 +public partition_14 +partition_14 = low_partition+0x20 +public partition_13 +partition_13 = low_partition+0x30 +public partition_12 +partition_12 = low_partition+0x40 +public partition_11 +partition_11 = low_partition+0x50 +public partition_10 +partition_10 = low_partition+0x60 +public partition_9 +partition_9 = low_partition+0x70 +public partition_8 +partition_8 = low_partition+0x80 +public partition_7 +partition_7 = low_partition+0x90 +public partition_6 +partition_6 = low_partition+0xA0 +public partition_5 +partition_5 = low_partition+0xB0 + endif + ! Now make sure this isn't to big! if *>partition_1 fail! Partition overlap |