1 files changed, 104 insertions, 0 deletions
diff --git a/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-mode-SwitchToPP16_32.asm b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-mode-SwitchToPP16_32.asm
new file mode 100644
index 00000000..9afdd9ed
--- /dev/null
+++ b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-mode-SwitchToPP16_32.asm
@@ -0,0 +1,104 @@
+; $Id: bs3-mode-SwitchToPP16_32.asm $
+;; @file
+; BS3Kit - Bs3SwitchToPP16_32
+;
+
+;
+; 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"
+
+
+;;
+; Switch to 32-bit code under 16-bit paged protected mode sys/tss from any other mode.
+;
+; @cproto   BS3_DECL(void) Bs3SwitchToPP16_32(void);
+;
+; @uses     Nothing (except high 32-bit register parts).
+;
+; @remarks  Obviously returns to 32-bit mode, even if the caller was
+;           in 16-bit or 64-bit mode.
+;
+; @remarks  Does not require 20h of parameter scratch space in 64-bit mode.
+;
+BS3_GLOBAL_NAME_EX TMPL_NM(Bs3SwitchToPP16_32_Safe), function, 0
+BS3_PROC_BEGIN_MODE Bs3SwitchToPP16_32, BS3_PBC_NEAR
+%ifdef TMPL_PP16_32
+        ret
+
+%else
+        ;
+        ; Make sure we're in the 16-bit segment and then call Bs3SwitchToPP16.
+        ;
+ %if TMPL_BITS != 16
+        jmp     .sixteen_bit_segment
+BS3_BEGIN_TEXT16
+        BS3_SET_BITS TMPL_BITS
+BS3_GLOBAL_LOCAL_LABEL .sixteen_bit_segment
+ %endif
+        extern  TMPL_NM(Bs3SwitchToPP16)
+        call    TMPL_NM(Bs3SwitchToPP16)
+        BS3_SET_BITS 16
+
+        ;
+        ; Switch to 32-bit mode.
+        ;
+        extern  _Bs3SwitchTo32Bit_c16
+ %if TMPL_BITS == 16
+        jmp     _Bs3SwitchTo32Bit_c16
+ %else
+        call    _Bs3SwitchTo32Bit_c16
+        BS3_SET_BITS 32
+  %if TMPL_BITS == 32
+        ret
+  %else
+        ret     4                       ; Return and pop 4 bytes of "parameters" (unused return address).
+  %endif
+ %endif
+%endif
+BS3_PROC_END_MODE   Bs3SwitchToPP16_32
+
+
+%if TMPL_BITS == 16
+;;
+; Custom far stub.
+BS3_BEGIN_TEXT16_FARSTUBS
+BS3_PROC_BEGIN_MODE Bs3SwitchToPP16_32, BS3_PBC_FAR
+        inc         bp
+        push        bp
+        mov         bp, sp
+
+        ; Call the real thing.
+        call        TMPL_NM(Bs3SwitchToPP16_32)
+        BS3_SET_BITS 32
+
+        ; Jmp to common code for the tedious conversion.
+ %if BS3_MODE_IS_RM_OR_V86(TMPL_MODE)
+        extern      _Bs3SwitchHlpConvRealModeRetfPopBpDecBpAndReturn_c32
+        jmp         _Bs3SwitchHlpConvRealModeRetfPopBpDecBpAndReturn_c32
+ %else
+        extern      _Bs3SwitchHlpConvProtModeRetfPopBpDecBpAndReturn_c32
+        jmp         _Bs3SwitchHlpConvProtModeRetfPopBpDecBpAndReturn_c32
+ %endif
+        BS3_SET_BITS 16
+BS3_PROC_END_MODE   Bs3SwitchToPP16_32
+%endif
+