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authorH. Peter Anvin <hpa@zytor.com>2010-06-21 10:23:20 -0700
committerH. Peter Anvin <hpa@zytor.com>2010-06-21 10:23:20 -0700
commit82f9fe073965be25be10f51c16070745575aa476 (patch)
tree173a25d9bd6d6f23f47c126b258406c03cdbc761
parent14b77079a892dc42219217688684ed9d6c4d0e3d (diff)
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diskstart: clean up GPT handling
We only need 56 bytes, not 92, and we should check for 0xED as the partition type. Signed-off-by: H. Peter Anvin <hpa@zytor.com>
-rw-r--r--core/diskstart.inc20
1 files changed, 11 insertions, 9 deletions
diff --git a/core/diskstart.inc b/core/diskstart.inc
index f557098b..40330dd5 100644
--- a/core/diskstart.inc
+++ b/core/diskstart.inc
@@ -22,7 +22,7 @@
PartInfo: ; Partition table info
.mbr: resb 16 ; MBR partition info
.gptlen: resd 1
-.gpt: resb 92
+.gpt: resb 56 ; GPT partition info (minus name)
FloppyTable resb 16 ; Floppy info table (must follow PartInfo)
section .init
@@ -121,10 +121,10 @@ start:
;
; DS:SI may contain a partition table entry and possibly a GPT entry.
-; Preserve it for us. This saves 92 bytes of the GPT entry, which is
-; currently the maximum we care about.
+; Preserve it for us. This saves 56 bytes of the GPT entry, which is
+; currently the maximum we care about. Total is 76 bytes.
;
- mov cl,(16+4+92)/2 ; Save partition info
+ mov cl,(16+4+56)/2 ; Save partition info
mov di,PartInfo
rep movsw ; This puts CX back to zero
@@ -158,7 +158,7 @@ floppy:
mov [bx+2],ax ; Segment 0
fs rep movsw ; Faster to move words
mov cl,[bsSecPerTrack] ; Patch the sector count
- mov [di-112+8],cl
+ mov [di-76+8],cl
int 13h ; Some BIOSes need this
push cx ; Partition offset == 0
@@ -174,17 +174,19 @@ floppy:
; Note: di points to beyond the end of PartInfo
;
harddisk:
- test byte [di-112],7Fh ; Sanity check: "active flag" should
+ test byte [di-76],7Fh ; Sanity check: "active flag" should
jnz no_partition ; be 00 or 80
cmp eax,'!GPT' ; !GPT signature?
jne .not_gpt
- push dword [di-112+20+36]
- push dword [di-112+20+32]
+ cmp byte [di-76+4],0EDh ; Synthetic GPT partition entry?
+ jne .not_gpt
+ push dword [di-76+20+36]
+ push dword [di-76+20+32]
jmp .gotoffs
.not_gpt:
push cx ; Upper half partition offset == 0
push cx
- push dword [di-112+8] ; Partition offset (dword)
+ push dword [di-76+8] ; Partition offset (dword)
.gotoffs:
no_partition:
;