diff options
Diffstat (limited to 'src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SelRealModeDataToProtFar16.asm')
| -rw-r--r-- | src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SelRealModeDataToProtFar16.asm | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SelRealModeDataToProtFar16.asm b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SelRealModeDataToProtFar16.asm new file mode 100644 index 00000000..33bb358a --- /dev/null +++ b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SelRealModeDataToProtFar16.asm @@ -0,0 +1,141 @@ +; $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 + |