diff options
Diffstat (limited to 'DuetPkg')
| -rw-r--r-- | DuetPkg/BootSector/bootsect.asm | 19 |
1 files changed, 16 insertions, 3 deletions
diff --git a/DuetPkg/BootSector/bootsect.asm b/DuetPkg/BootSector/bootsect.asm index 8fb7236bc1..1b8c15bc80 100644 --- a/DuetPkg/BootSector/bootsect.asm +++ b/DuetPkg/BootSector/bootsect.asm @@ -9,9 +9,22 @@ ;* THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
;* WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
;*
-;* bootsect.asm
-;*
-;* Abstract:
+;* bootsect.asm
+;*
+;* bootsect.asm is built as 16-bit binary file in 512 bytes and patched to disk/partition's
+;* first section - boot sector.
+;*
+;* The startup sequence for DUET disk boot sector is:
+;*
+;* 1, LegacyBios check 0xAA55 signature at boot sectore offset 0x1FE to judget
+;* whether disk/partition is bootable.
+;* 2, LegacyBios will load boot sector to 0x7c00 in real mode, pass BPB data and
+;* hand off control to 0x7c00 code.
+;* 3, boot sector code simply parse FAT format in boot disk and find EfiLdr binary file
+;* and EfiVar.bin if exists. For first boot, EfiVar.bin does not exist.
+;* 4, boot sector load the first sector of EfiLdr binary which is start.com to
+;* 0x2000:0x0000 address.
+;* 5, boot sector handoff control to 0x2000:0x0000 for start.com binary.
;*
;------------------------------------------------------------------------------
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