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; $Id: bs3-cmn-SelFlatDataToProtFar16.asm $
;; @file
; BS3Kit - Bs3SelFlatDataToProtFar16.
;
;
; 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 *
;*********************************************************************************************************************************
%ifdef BS3_STRICT
BS3_EXTERN_CMN Bs3Panic
%endif
TMPL_BEGIN_TEXT
%if TMPL_BITS == 16
CPU 8086
%endif
;;
; @cproto BS3_CMN_PROTO_NOSB(uint32_t, Bs3SelFlatDataToProtFar16,(uint32_t uFlatAddr));
;
; @uses Only return registers (ax:dx, eax, eax)
; @remarks No 20h scratch area requirements.
;
BS3_PROC_BEGIN_CMN Bs3SelFlatDataToProtFar16, BS3_PBC_NEAR ; Far stub generated by the makefile/bs3kit.h.
push xBP
mov xBP, xSP
;
; Check if we can use the protected mode stack or data selector.
; The latter ensures the usability of this function for setting SS.
;
%if TMPL_BITS == 16
mov ax, [xBP + xCB + cbCurRetAddr]
mov dx, [xBP + xCB + cbCurRetAddr + 2]
test dx, dx
jnz .not_stack
mov dx, BS3_SEL_R0_SS16
%else
TNOT64 mov eax, [xBP + xCB + cbCurRetAddr]
TONLY64 mov eax, ecx
test eax, 0ffff0000h
jnz .not_stack
or eax, BS3_SEL_R0_SS16 << 16
%endif
jmp .return
.not_stack:
%if TMPL_BITS == 16
sub ax, BS3_ADDR_BS3DATA16 & 0xffff
sbb dx, BS3_ADDR_BS3DATA16 >> 16
jnz .do_tiled
mov dx, BS3_SEL_R0_DS16
%else
sub eax, BS3_ADDR_BS3DATA16
test eax, 0ffff0000h
jnz .do_tiled
or eax, BS3_SEL_R0_DS16 << 16
%endif
jmp .return
;
; Just translate the address to tiled.
;
.do_tiled:
%if TMPL_BITS == 16
; Convert upper 16-bit to a tiled selector.
mov ax, cx ; save cx
mov dx, [xBP + xCB + cbCurRetAddr + 2]
%ifdef BS3_STRICT
cmp dx, BS3_SEL_TILED_AREA_SIZE >> 16
jb .address_ok
call Bs3Panic
.address_ok:
%endif
mov cl, X86_SEL_SHIFT
shl dx, cl
add dx, BS3_SEL_TILED
mov cx, ax ; restore cx
; Load segment offset and return.
mov ax, [xBP + xCB + cbCurRetAddr]
%else
; Convert upper 16-bit to tiled selector.
TNOT64 mov eax, [xBP + xCB + cbCurRetAddr]
TONLY64 mov rax, rcx
%ifdef BS3_STRICT
cmp xAX, BS3_SEL_TILED_AREA_SIZE
jb .address_ok
call Bs3Panic
.address_ok:
%endif
ror eax, 16
shl ax, X86_SEL_SHIFT
add ax, BS3_SEL_TILED
rol eax, 16
%endif
.return:
pop xBP
BS3_HYBRID_RET
BS3_PROC_END_CMN Bs3SelFlatDataToProtFar16
|
