; $Id: bs3-cmn-SelProtFar16DataToRealMode.asm $ ;; @file ; BS3Kit - Bs3SelProtFar16DataToRealMode. ; ; ; 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. ; ;********************************************************************************************************************************* ;* 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