isolinux: make sure Hidden is zero in native El Torito mode

In native El Torito mode, there is no such thing as a partition
offset.  Make sure that we set Hidden to zero -- we don't use Hidden
(yet, although the ebios and cdrom code should be merged!) but we pass
it to the PM code, which will produce *really* wrong results...

Reported-by: Helmut Hullen <Hullen@t-online.de>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

diff --git a/core/isolinux.asm b/core/isolinux.asm
index d9d630e..656bbfb 100644 (file)
--- a/core/isolinux.asm
+++ b/core/isolinux.asm
@@ -101,7 +101,7 @@ ISOFlags    resb 1                  ; Flags for ISO directory search
 RetryCount      resb 1                 ; Used for disk access retries
 
                alignb 8
-Hidden resq 1                  ; Used in hybrid mode
+Hidden         resq 1                  ; Used in hybrid mode
 bsSecPerTrack  resw 1                  ; Used in hybrid mode
 bsHeads                resw 1                  ; Used in hybrid mode
 
@@ -242,9 +242,6 @@ _start_hybrid:
                pop eax
                pop ebx
 .nooffset:
-               mov [cs:Hidden],eax
-               mov [cs:Hidden+4],ebx
-
                mov si,bios_cbios
                jcxz _start_common
                mov si,bios_ebios
@@ -253,21 +250,26 @@ _start_hybrid:
 
 _start1:
                mov si,bios_cdrom
+               xor eax,eax
+               xor ebx,ebx
 _start_common:
                mov [cs:InitStack],sp   ; Save initial stack pointer
                mov [cs:InitStack+2],ss
-               xor ax,ax
-               mov ss,ax
+               xor dx,dx
+               mov ss,dx
                mov sp,StackBuf         ; Set up stack
                push es                 ; Save initial ES:DI -> $PnP pointer
                push di
-               mov ds,ax
-               mov es,ax
-               mov fs,ax
-               mov gs,ax
+               mov ds,dx
+               mov es,dx
+               mov fs,dx
+               mov gs,dx
                sti
                cld
 
+               mov [Hidden],eax
+               mov [Hidden+4],ebx
+
                mov [BIOSType],si
                mov eax,[si]
                mov [GetlinsecPtr],eax