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Bochs/bochs/cpu/vm8086.cc

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/////////////////////////////////////////////////////////////////////////
// $Id: vm8086.cc,v 1.9 2002-03-01 17:27:25 bdenney 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"
#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_SUPPORT_V8086_MODE
#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, 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 in upper 16bits of eFLAGS
// 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 #GP(0)
if ( !can_pop(36) ) {
BX_PANIC(("iret: VM: top 36 bytes not within limits"));
exception(BX_SS_EXCEPTION, 0, 0);
return;
}
if ( new_eip & 0xffff0000 ) {
BX_INFO(("IRET to V86-mode: ignoring upper 16-bits"));
new_eip = new_eip & 0xffff;
}
esp_laddr = BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.base +
temp_ESP;
// load SS:ESP from stack
access_linear(esp_laddr + 12, 4, 0, BX_READ, &new_esp);
access_linear(esp_laddr + 16, 2, 0, BX_READ, &raw_ss_selector);
// load ES,DS,FS,GS from stack
access_linear(esp_laddr + 20, 2, 0, BX_READ, &raw_es_selector);
access_linear(esp_laddr + 24, 2, 0, BX_READ, &raw_ds_selector);
access_linear(esp_laddr + 28, 2, 0, BX_READ, &raw_fs_selector);
access_linear(esp_laddr + 32, 2, 0, BX_READ, &raw_gs_selector);
write_eflags(flags32, /*change IOPL*/ 1, /*change IF*/ 1,
/*change VM*/ 1, /*change RF*/ 1);
// load CS:EIP 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;
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 32bits are loaded.
init_v8086_mode();
}
void
BX_CPU_C::stack_return_from_v86(BxInstruction_t *i)
{
static Bit32u times = 0;
times++;
if (times<100) {
BX_ERROR(("stack_return_from_v86 may not be implemented right!"));
} else if (times==100) {
BX_ERROR(("stack_return_from_v86 called 100 times. I won't print this error any more"));
}
//exception(BX_GP_EXCEPTION, 0, 0);
#if 1
if (IOPL != 3) {
// trap to virtual 8086 monitor
BX_ERROR(("stack_return_from_v86: IOPL != 3"));
exception(BX_GP_EXCEPTION, 0, 0);
}
if (i->os_32) {
Bit32u eip, ecs_raw, eflags;
// ??? should be some stack checks here
pop_32(&eip);
pop_32(&ecs_raw);
pop_32(&eflags);
load_seg_reg(&BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS], (Bit16u) ecs_raw);
BX_CPU_THIS_PTR eip = eip;
write_eflags(eflags, /*IOPL*/ CPL==0, /*IF*/ 1, /*VM*/ 0, /*RF*/ 1);
}
else {
Bit16u ip, cs_raw, flags;
// ??? should be some stack checks here
pop_16(&ip);
pop_16(&cs_raw);
pop_16(&flags);
load_seg_reg(&BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS], cs_raw);
BX_CPU_THIS_PTR eip = (Bit32u) ip;
write_flags(flags, /*IOPL*/ CPL==0, /*IF*/ 1);
}
#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.u.segment.executable = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.c_ed = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.r_w = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_CS].cache.u.segment.a = 1;
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;
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.u.segment.executable = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.c_ed = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.r_w = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_SS].cache.u.segment.a = 1;
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.u.segment.executable = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].cache.u.segment.c_ed = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].cache.u.segment.r_w = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_ES].cache.u.segment.a = 1;
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.u.segment.executable = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].cache.u.segment.c_ed = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].cache.u.segment.r_w = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_DS].cache.u.segment.a = 1;
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.u.segment.executable = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].cache.u.segment.c_ed = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].cache.u.segment.r_w = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_FS].cache.u.segment.a = 1;
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.u.segment.executable = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].cache.u.segment.c_ed = 0;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].cache.u.segment.r_w = 1;
BX_CPU_THIS_PTR sregs[BX_SEG_REG_GS].cache.u.segment.a = 1;
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 */
#else // BX_SUPPORT_V8086_MODE
// non-support of v8086 mode
void
BX_CPU_C::stack_return_to_v86(Bit32u new_eip, Bit32u raw_cs_selector, Bit32u flags32)
{
BX_INFO(("stack_return_to_v86: VM bit set in EFLAGS stack image"));
v8086_message();
}
void
BX_CPU_C::stack_return_from_v86(void)
{
BX_INFO(("stack_return_from_v86:"));
v8086_message();
}
void
BX_CPU_C::v8086_message(void)
{
BX_INFO(("Program compiled with BX_SUPPORT_V8086_MODE = 0"));
BX_INFO(("You need to rerun the configure script and recompile"));
BX_INFO((" to use virtual-8086 mode features."));
BX_PANIC(("Bummer!"));
}
#endif // BX_SUPPORT_V8086_MODE
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