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|
; $Id: bs3-cmn-SelRealModeDataToProtFar16.asm $
;; @file
; BS3Kit - Bs3SelRealModeDataToProtFar16.
;
;
; 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
%if TMPL_BITS == 16
CPU 8086
%endif
;;
; @cproto BS3_CMN_PROTO_NOSB(uint32_t, Bs3SelRealModeDataToProtFar16,(uint32_t uFar1616));
;
; @uses Only return registers (ax:dx, eax, eax)
; @remarks No 20h scratch area requirements.
;
BS3_PROC_BEGIN_CMN Bs3SelRealModeDataToProtFar16, BS3_PBC_NEAR ; Far stub generated by the makefile/bs3kit.h.
push xBP
mov xBP, xSP
;
; See if it's our default 16-bit 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, 0
jnz .not_stack
mov ax, BS3_SEL_R0_SS16
.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, BS3KIT_GRPNM_DATA16
jne .not_dgroup
mov ax, BS3_SEL_R0_DS16
jmp .quick_return
.not_dgroup:
cmp ax, BS3SYSTEM16
jne .not_system16
mov ax, BS3_SEL_SYSTEM16
jmp .quick_return
;
; Compute flat address and translate it to tiled.
;
.not_system16:
%if TMPL_BITS == 16
push cx
; Calc flat address.
mov dx, ax
mov cl, 12
shr dx, cl
mov cl, 4
shl ax, cl
add ax, [xBP + xCB + cbCurRetAddr]
adc dx, 0
; Convert upper 16-bit to tiled selector.
mov cl, X86_SEL_SHIFT
shl dx, cl
add dx, BS3_SEL_TILED
pop cx
%else
; Calc flat address.
shl eax, 4
%if TMPL_BITS == 32
add ax, [xBP + xCB + cbCurRetAddr]
%else
add ax, cx
%endif
jnc .no_carry
add eax, 10000h
.no_carry:
; 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 Bs3SelRealModeDataToProtFar16
|
