isolinux: can't clobber edx when dx contains the drive number...

Use ebx to hold the upper half of the partition offset, not edx.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

diff --git a/core/isolinux.asm b/core/isolinux.asm
index 38d3d71..2627c2d 100644 (file)
--- a/core/isolinux.asm
+++ b/core/isolinux.asm
@@ -249,14 +249,14 @@ _start_hybrid:
                pop di
                pop es
                xor eax,eax
-               xor edx,edx
+               xor ebx,ebx
                cmp sp,7C00h
                jae .nooffset
                pop eax
-               pop edx
+               pop ebx
 .nooffset:
                mov [cs:bsHidden],eax
-               mov [cs:bsHidden+4],edx
+               mov [cs:bsHidden+4],ebx
 
                mov si,bios_cbios
                jcxz _start_common