[tkreuzer] 54145: [ISOBTRT] call it 13h with es set to 0, instead of the transfer buffer segment, that we loaded it with. Fixes KVM boot.

Author: tkreuzer
Date: Sat Oct 15 13:42:43 2011
New Revision: 54145
URL: http://svn.reactos.org/svn/reactos?rev=54145&view=rev
Log:
[ISOBTRT]
call it 13h with es set to 0, instead of the transfer buffer segment, that we loaded it
with. Fixes KVM boot.
Modified:
    trunk/reactos/boot/freeldr/bootsect/isoboot.S
Modified: trunk/reactos/boot/freeldr/bootsect/isoboot.S
URL:
http://svn.reactos.org/svn/reactos/trunk/reactos/boot/freeldr/bootsect/isob…
==============================================================================
--- trunk/reactos/boot/freeldr/bootsect/isoboot.S [iso-8859-1] (original)
+++ trunk/reactos/boot/freeldr/bootsect/isoboot.S [iso-8859-1] Sat Oct 15 13:42:43 2011
@@ -144,7 +144,11 @@
     jc .boot_cdrom          // could not read hdd
     push ax
+#ifdef ROS_REGTEST // this change is taken from the original isobtrt.asm
+    mov ax, word ptr ds:[trackbuf+510]
+#else
     mov ax, word ptr ds:[trackbuf]
+#endif
     cmp ax, 0
     je .boot_cdrom // no boot sector found (hopefully there are no weird bootsectors
which begin with 0)
     pop ax
@@ -810,10 +814,14 @@
 //    BP    - Sector count
 //
 getlinsec:
+    push es // save es, we reset it later to 0
+
     mov si, offset dapa            // Load up the DAPA
     mov word ptr ds:[si+4], bx
     mov bx, es
     mov word ptr ds:[si+6], bx
+    xor bx, bx // reset es to 0, some bioses (KVM) require that
+    mov es, bx
     mov dword ptr ds:[si+8], eax
 .loop2:
     push bp                // Sectors left
@@ -836,6 +844,8 @@
     and bp, bp
     jnz .loop2
     mov eax, dword ptr ds:[si+8]            // Next sector
+
+    pop es
     ret
     // INT 13h with retry