diff options
Diffstat (limited to 'src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SelProtFar16DataToRealMode.asm')
| -rw-r--r-- | src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SelProtFar16DataToRealMode.asm | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SelProtFar16DataToRealMode.asm b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SelProtFar16DataToRealMode.asm new file mode 100644 index 00000000..b244adf8 --- /dev/null +++ b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SelProtFar16DataToRealMode.asm @@ -0,0 +1,157 @@ +; $Id: bs3-cmn-SelProtFar16DataToRealMode.asm $ +;; @file +; BS3Kit - Bs3SelProtFar16DataToRealMode. +; + +; +; Copyright (C) 2007-2023 Oracle and/or its affiliates. +; +; This file is part of VirtualBox base platform packages, as +; available from https://www.virtualbox.org. +; +; This program is free software; you can redistribute it and/or +; modify it under the terms of the GNU General Public License +; as published by the Free Software Foundation, in version 3 of the +; License. +; +; This program is distributed in the hope that it will be useful, but +; WITHOUT ANY WARRANTY; without even the implied warranty of +; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +; General Public License for more details. +; +; You should have received a copy of the GNU General Public License +; along with this program; if not, see <https://www.gnu.org/licenses>. +; +; The contents of this file may alternatively be used under the terms +; of the Common Development and Distribution License Version 1.0 +; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included +; in the VirtualBox 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. +; +; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0 +; + + +;********************************************************************************************************************************* +;* Header Files * +;********************************************************************************************************************************* +%include "bs3kit-template-header.mac" + + +;********************************************************************************************************************************* +;* External Symbols * +;********************************************************************************************************************************* +BS3_BEGIN_DATA16 ; For real mode segment value. +BS3_BEGIN_SYSTEM16 ; Ditto. +TMPL_BEGIN_TEXT +BS3_EXTERN_CMN Bs3SelFar32ToFlat32NoClobber + +TMPL_BEGIN_TEXT +%if TMPL_BITS == 16 +CPU 8086 +%endif + + +;; +; @cproto BS3_CMN_PROTO_NOSB(uint32_t, Bs3SelProtFar16DataToRealMode,(uint32_t uFar1616)); +; +; @uses Only return registers (ax:dx, eax, eax) +; @remarks No 20h scratch area requirements. +; +BS3_PROC_BEGIN_CMN Bs3SelProtFar16DataToRealMode, BS3_PBC_NEAR ; Far stub generated by the makefile/bs3kit.h. + push xBP + mov xBP, xSP + + ; + ; See if it's our default 16-bit ring-0 data, stack or system data segment. + ; +%if TMPL_BITS == 16 + mov ax, [xBP + xCB + cbCurRetAddr + 2] +%elif TMPL_BITS == 32 + movzx eax, word [xBP + xCB + cbCurRetAddr + 2] +%else + mov eax, ecx + shr eax, 16 +%endif + cmp ax, BS3_SEL_R0_SS16 + jne .not_stack + mov ax, 0 + +.quick_return: +%if TMPL_BITS == 16 + mov dx, ax + mov ax, [xBP + xCB + cbCurRetAddr] +%elif TMPL_BITS == 32 + shl eax, 16 + mov ax, word [xBP + xCB + cbCurRetAddr] +%else + shl eax, 16 + mov ax, cx +%endif + +.return: + pop xBP + BS3_HYBRID_RET + +.not_stack: + cmp ax, BS3_SEL_R0_DS16 + jne .not_dgroup + mov ax, BS3KIT_GRPNM_DATA16 + jmp .quick_return + +.not_dgroup: + cmp ax, BS3_SEL_SYSTEM16 + jne .not_system16 + mov ax, BS3SYSTEM16 + jmp .quick_return + + ; + ; Call worker function to convert it to flat and the do tiled + ; calculation from that. + ; +.not_system16: +%if TMPL_BITS == 16 + push word [xBP + xCB + cbCurRetAddr + 2] + xor ax, ax + push ax + push word [xBP + xCB + cbCurRetAddr] + call Bs3SelFar32ToFlat32NoClobber + add sp, 6 + + ; Convert upper 16-bit of the flat address to a tiled selector. + push cx + mov cl, X86_SEL_SHIFT + shl dx, cl + add dx, BS3_SEL_TILED + pop cx +%else + %if TMPL_BITS == 32 + push eax + movzx eax, word [xBP + xCB + cbCurRetAddr] + push eax + call Bs3SelFar32ToFlat32NoClobber + add esp, 8 + %else + push xDX + push xCX + + mov edx, eax ; arg #2: selector + movzx ecx, cx ; arg #1: offset + call Bs3SelFar32ToFlat32NoClobber + + pop xDX + pop xCX + %endif + + ; Convert upper 16-bit to tiled selector. + rol eax, 16 + shl ax, X86_SEL_SHIFT + add ax, BS3_SEL_TILED + ror eax, 16 +%endif + jmp .return +BS3_PROC_END_CMN Bs3SelProtFar16DataToRealMode + |