1 files changed, 79 insertions, 0 deletions
diff --git a/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-RegGetDr3.asm b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-RegGetDr3.asm
new file mode 100644
index 00000000..4842d2fa
--- /dev/null
+++ b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-RegGetDr3.asm
@@ -0,0 +1,79 @@
+; $Id: bs3-cmn-RegGetDr3.asm $
+;; @file
+; BS3Kit - Bs3RegGetDr3
+;
+
+;
+; Copyright (C) 2007-2019 Oracle Corporation
+;
+; This file is part of VirtualBox Open Source Edition (OSE), as
+; available from http://www.virtualbox.org. This file is free software;
+; you can redistribute it and/or modify it under the terms of the GNU
+; General Public License (GPL) as published by the Free Software
+; Foundation, in version 2 as it comes in the "COPYING" file of the
+; VirtualBox OSE distribution. VirtualBox OSE is distributed in the
+; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
+;
+; The contents of this file may alternatively be used under the terms
+; of the Common Development and Distribution License Version 1.0
+; (CDDL) only, as it comes in the "COPYING.CDDL" file of the
+; VirtualBox OSE distribution, in which case the provisions of the
+; CDDL are applicable instead of those of the GPL.
+;
+; You may elect to license modified versions of this file under the
+; terms and conditions of either the GPL or the CDDL or both.
+;
+
+%include "bs3kit-template-header.mac"
+
+
+BS3_EXTERN_CMN Bs3Panic
+BS3_EXTERN_CMN Bs3Syscall
+%if TMPL_BITS == 16
+BS3_EXTERN_DATA16 g_bBs3CurrentMode
+%endif
+TMPL_BEGIN_TEXT
+
+
+;;
+; @cproto   BS3_CMN_PROTO_STUB(RTCCUINTXREG, Bs3RegGetDr3,(void));
+;
+; @returns  Register value.
+; @remarks  Does not require 20h of parameter scratch space in 64-bit mode.
+;
+; @uses     No GPRs (only return full register(s)).
+;
+BS3_PROC_BEGIN_CMN Bs3RegGetDr3, BS3_PBC_HYBRID_SAFE
+        BS3_CALL_CONV_PROLOG 0
+        push    xBP
+        mov     xBP, xSP
+
+%if TMPL_BITS == 16
+        ; If V8086 mode we have to go thru a syscall.
+        test    byte [BS3_DATA16_WRT(g_bBs3CurrentMode)], BS3_MODE_CODE_V86
+        jnz     .via_system_call
+        cmp     byte [BS3_DATA16_WRT(g_bBs3CurrentMode)], BS3_MODE_RM
+        je      .direct_access
+%endif
+        ; If not in ring-0, we have to make a system call.
+        mov     ax, ss
+        and     ax, X86_SEL_RPL
+        jnz     .via_system_call
+
+.direct_access:
+        mov     sAX, dr3
+TONLY16 mov     edx, eax
+TONLY16 shr     edx, 16
+        jmp     .return
+
+.via_system_call:
+        mov     xAX, BS3_SYSCALL_GET_DRX
+        mov     dl, 3
+        call    Bs3Syscall
+
+.return:
+        pop     xBP
+        BS3_CALL_CONV_EPILOG 0
+        BS3_HYBRID_RET
+BS3_PROC_END_CMN   Bs3RegGetDr3
+