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Bochs/bochs/cpu/vm8086.cc

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/////////////////////////////////////////////////////////////////////////
// $Id: vm8086.cc,v 1.37 2008-01-29 17:13:09 sshwarts Exp $
/////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2001 MandrakeSoft S.A.
//
// MandrakeSoft S.A.
// 43, rue d'Aboukir
// 75002 Paris - France
// http://www.linux-mandrake.com/
// http://www.mandrakesoft.com/
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
//
// This library 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
// Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
/////////////////////////////////////////////////////////////////////////
#define NEED_CPU_REG_SHORTCUTS 1
#include "bochs.h"
#include "cpu.h"
#define LOG_THIS BX_CPU_THIS_PTR
//
// Notes:
//
// The high bits of the 32bit eip image are ignored by
// the IRET to VM. The high bits of the 32bit esp image
// are loaded into ESP. A subsequent push uses
// only the low 16bits since it's in VM. In neither case
// did a protection fault occur during actual tests. This
// is contrary to the Intel docs which claim a #GP for
// eIP out of code limits.
//
// IRET to VM does affect IOPL, IF, VM, and RF
//
#if BX_CPU_LEVEL >= 3
void BX_CPU_C::stack_return_to_v86(Bit32u new_eip, Bit32u raw_cs_selector,
Bit32u flags32)
{
Bit32u temp_ESP, new_esp;
bx_address esp_laddr;
Bit16u raw_es_selector, raw_ds_selector, raw_fs_selector,
raw_gs_selector, raw_ss_selector;
// Must be 32bit effective opsize, VM is set in upper 16bits of eFLAGS
// and CPL = 0 to get here
// ----------------
// | | OLD GS | eSP+32
// | | OLD FS | eSP+28
// | | OLD DS | eSP+24
// | | OLD ES | eSP+20
// | | OLD SS | eSP+16
// | OLD ESP | eSP+12
// | OLD EFLAGS | eSP+8
// | | OLD CS | eSP+4
// | OLD EIP | eSP+0
// ----------------
if (BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.d_b)
temp_ESP = ESP;
else
temp_ESP = SP;
// top 36 bytes of stack must be within stack limits, else #SS(0)
if ( !can_pop(36) ) {
BX_ERROR(("stack_return_to_v86: top 36 bytes not within limits"));
exception(BX_SS_EXCEPTION, 0, 0);
}
esp_laddr = BX_CPU_THIS_PTR get_segment_base(BX_SEG_REG_SS) + temp_ESP;
// load SS:ESP from stack
new_esp = read_virtual_dword(BX_SEG_REG_SS, temp_ESP+12);
raw_ss_selector = read_virtual_word(BX_SEG_REG_SS, temp_ESP+16);
// load ES,DS,FS,GS from stack
raw_es_selector = read_virtual_word(BX_SEG_REG_SS, temp_ESP+20);
raw_ds_selector = read_virtual_word(BX_SEG_REG_SS, temp_ESP+24);
raw_fs_selector = read_virtual_word(BX_SEG_REG_SS, temp_ESP+28);
raw_gs_selector = read_virtual_word(BX_SEG_REG_SS, temp_ESP+32);
writeEFlags(flags32, EFlagsValidMask);
// load CS:IP from stack; already read and passed as args
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value = raw_cs_selector;
EIP = new_eip & 0xffff;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].selector.value = raw_es_selector;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].selector.value = raw_ds_selector;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].selector.value = raw_fs_selector;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].selector.value = raw_gs_selector;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].selector.value = raw_ss_selector;
ESP = new_esp; // full 32 bit are loaded
init_v8086_mode();
}
void BX_CPU_C::iret16_stack_return_from_v86(bxInstruction_c *i)
{
if ((BX_CPU_THIS_PTR get_IOPL() < 3) && (CR4_VME_ENABLED == 0)) {
// trap to virtual 8086 monitor
BX_DEBUG(("IRET in vm86 with IOPL != 3, VME = 0"));
exception(BX_GP_EXCEPTION, 0, 0);
}
Bit16u ip, cs_raw, flags16;
if( !can_pop(6) )
{
BX_DEBUG(("iret16_stack_return_from_v86(): can't pop 6 bytes from the stack"));
exception(BX_SS_EXCEPTION, 0, 0);
}
ip = pop_16();
cs_raw = pop_16();
flags16 = pop_16();
#if BX_SUPPORT_VME
if (CR4_VME_ENABLED && BX_CPU_THIS_PTR get_IOPL() < 3)
{
if (((flags16 & EFlagsIFMask) && BX_CPU_THIS_PTR get_VIP()) ||
(flags16 & EFlagsTFMask))
{
BX_DEBUG(("iret16_stack_return_from_v86(): #GP(0) in VME mode"));
exception(BX_GP_EXCEPTION, 0, 0);
}
load_seg_reg(&BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS], cs_raw);
EIP = (Bit32u) ip;
// IF, IOPL unchanged, EFLAGS.VIF = TMP_FLAGS.IF
Bit32u changeMask = EFlagsOSZAPCMask | EFlagsTFMask |
EFlagsDFMask | EFlagsNTMask | EFlagsVIFMask;
Bit32u flags32 = (Bit32u) flags16;
if (BX_CPU_THIS_PTR get_IF()) flags32 |= EFlagsVIFMask;
writeEFlags(flags32, changeMask);
return;
}
#endif
load_seg_reg(&BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS], cs_raw);
EIP = (Bit32u) ip;
write_flags(flags16, /*IOPL*/ 0, /*IF*/ 1);
}
void BX_CPU_C::iret32_stack_return_from_v86(bxInstruction_c *i)
{
if (BX_CPU_THIS_PTR get_IOPL() < 3) {
// trap to virtual 8086 monitor
BX_DEBUG(("IRET in vm86 with IOPL != 3, VME = 0"));
exception(BX_GP_EXCEPTION, 0, 0);
}
Bit32u eip, cs_raw, flags32;
// Build a mask of the following bits:
// ID,VIP,VIF,AC,VM,RF,x,NT,IOPL,OF,DF,IF,TF,SF,ZF,x,AF,x,PF,x,CF
Bit32u change_mask = EFlagsOSZAPCMask | EFlagsTFMask | EFlagsIFMask
| EFlagsDFMask | EFlagsNTMask | EFlagsRFMask;
#if BX_CPU_LEVEL >= 4
change_mask |= (EFlagsIDMask | EFlagsACMask); // ID/AC
#endif
if( !can_pop(12) )
{
BX_DEBUG(("iret32_stack_return_from_v86(): can't pop 12 bytes from the stack"));
exception(BX_SS_EXCEPTION, 0, 0);
}
eip = pop_32();
cs_raw = pop_32();
flags32 = pop_32();
load_seg_reg(&BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS], (Bit16u) cs_raw);
EIP = eip;
// VIF, VIP, VM, IOPL unchanged
writeEFlags(flags32, change_mask);
}
#if BX_SUPPORT_VME
void BX_CPU_C::v86_redirect_interrupt(Bit32u vector)
{
Bit16u temp_IP, temp_CS, temp_flags = read_flags();
access_linear(vector*4, 2, 0, BX_READ, &temp_IP);
access_linear(vector*4 + 2, 2, 0, BX_READ, &temp_CS);
if (BX_CPU_THIS_PTR get_IOPL() < 3) {
temp_flags |= EFlagsIOPLMask;
if (BX_CPU_THIS_PTR get_VIF())
temp_flags |= EFlagsIFMask;
else
temp_flags &= ~EFlagsIFMask;
}
Bit16u old_IP = IP;
Bit16u old_CS = BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value;
push_16(temp_flags);
// push return address onto new stack
push_16(old_CS);
push_16(old_IP);
load_seg_reg(&BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS], (Bit16u) temp_CS);
EIP = temp_IP;
BX_CPU_THIS_PTR clear_TF();
BX_CPU_THIS_PTR clear_RF();
if (BX_CPU_THIS_PTR get_IOPL() == 3)
BX_CPU_THIS_PTR clear_IF ();
else
BX_CPU_THIS_PTR clear_VIF();
}
#endif
void BX_CPU_C::init_v8086_mode(void)
{
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.valid = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.p = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.dpl = 3;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.segment = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.type = BX_CODE_EXEC_READ_ACCESSED;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.base =
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.value << 4;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.limit = 0xffff;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.limit_scaled = 0xffff;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.g = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.d_b = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.avl = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].selector.rpl = 3;
#if BX_SUPPORT_ICACHE // update instruction cache
BX_CPU_THIS_PTR updateFetchModeMask();
#endif
#if BX_CPU_LEVEL >= 4 && BX_SUPPORT_ALIGNMENT_CHECK
handleAlignmentCheck(); // CPL was modified
#endif
BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.valid = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.p = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.dpl = 3;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.segment = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.type = BX_DATA_READ_WRITE_ACCESSED;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.base =
BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].selector.value << 4;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.limit = 0xffff;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.limit_scaled = 0xffff;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.g = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.d_b = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.avl = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].selector.rpl = 3;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].cache.valid = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].cache.p = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].cache.dpl = 3;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].cache.segment = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].cache.type = BX_DATA_READ_WRITE_ACCESSED;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].cache.u.segment.base =
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].selector.value << 4;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].cache.u.segment.limit = 0xffff;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].cache.u.segment.limit_scaled = 0xffff;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].cache.u.segment.g = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].cache.u.segment.d_b = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].cache.u.segment.avl = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].selector.rpl = 3;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].cache.valid = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].cache.p = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].cache.dpl = 3;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].cache.segment = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].cache.type = BX_DATA_READ_WRITE_ACCESSED;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].cache.u.segment.base =
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].selector.value << 4;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].cache.u.segment.limit = 0xffff;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].cache.u.segment.limit_scaled = 0xffff;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].cache.u.segment.g = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].cache.u.segment.d_b = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].cache.u.segment.avl = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].selector.rpl = 3;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].cache.valid = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].cache.p = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].cache.dpl = 3;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].cache.segment = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].cache.type = BX_DATA_READ_WRITE_ACCESSED;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].cache.u.segment.base =
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].selector.value << 4;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].cache.u.segment.limit = 0xffff;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].cache.u.segment.limit_scaled = 0xffff;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].cache.u.segment.g = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].cache.u.segment.d_b = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].cache.u.segment.avl = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].selector.rpl = 3;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].cache.valid = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].cache.p = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].cache.dpl = 3;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].cache.segment = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].cache.type = BX_DATA_READ_WRITE_ACCESSED;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].cache.u.segment.base =
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].selector.value << 4;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].cache.u.segment.limit = 0xffff;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].cache.u.segment.limit_scaled = 0xffff;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].cache.u.segment.g = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].cache.u.segment.d_b = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].cache.u.segment.avl = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].selector.rpl = 3;
}
#endif /* BX_CPU_LEVEL >= 3 */
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