diff options
| -rw-r--r-- | DuetPkg/BootSector/bootsect.asm | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/DuetPkg/BootSector/bootsect.asm b/DuetPkg/BootSector/bootsect.asm index 972e36e8a1..8fb7236bc1 100644 --- a/DuetPkg/BootSector/bootsect.asm +++ b/DuetPkg/BootSector/bootsect.asm @@ -81,13 +81,13 @@ BootSectorEntryPoint: mov ah,8 ; ah = 8 - Get Drive Parameters Function
mov byte ptr [bp+PhysicalDrive],dl ; BBS defines that BIOS would pass the booting driver number to the loader through DL
int 13h ; Get Drive Parameters
- xor ax,ax ; ax = 0
- mov al,dh ; al = dh
- inc al ; MaxHead = al + 1
- push ax ; 0000:7bfe = MaxHead
- mov al,cl ; al = cl
- and al,03fh ; MaxSector = al & 0x3f
- push ax ; 0000:7bfc = MaxSector
+ xor ax,ax ; ax = 0
+ mov al,dh ; al = dh (number of sides (0 based))
+ inc al ; MaxHead = al + 1
+ push ax ; 0000:7bfe = MaxHead
+ mov al,cl ; al = cl (CL = sectors per track)
+ and al,03fh ; MaxSector = al & 0x3f
+ push ax ; 0000:7bfc = MaxSector
cmp word ptr [bp+SectorSignature],0aa55h ; Verify Boot Sector Signature
jne BadBootSector
@@ -149,7 +149,7 @@ FindNext: jmp NotFoundAll
FoundAll:
-FoundEFILDR:
+FoundEFILDR: ; 0x7cfe
mov cx,bx ; cx = Start Cluster for EFILDR <----------------------------------
mov ax,cs ; Destination = 2000:0000
add ax,2000h
@@ -170,8 +170,8 @@ ReadFirstClusterOfEFILDR: call ReadBlocks
pop ax
JumpIntoFirstSectorOfEFILDR:
- mov word ptr [bp+JumpSegment],ax
-JumpFarInstruction:
+ mov word ptr [bp+JumpSegment],ax ; 0x7d26
+JumpFarInstruction: ; 0x7d2a
db 0eah
JumpOffset:
dw 0000h
@@ -252,7 +252,7 @@ LimitTransfer: ; ****************************************************************************
; ERROR Condition:
; ****************************************************************************
-NotFoundAll:
+NotFoundAll: ; 0x7da6
; if we found EFILDR, continue
test bx,bx
jne FoundEFILDR
|