b742ccec7e
of (1 & (val32>>N)), and added a getB_?F() accessor for special cases which need a strict binary value (exactly 0 or 1). Most code only needed a value for logical comparison. I modified the special cases which do need a binary number for shifting and comparison between flags, to use the special getB_?F() accessor. Cleaned up memory.cc functions a little, now that all accesses are within a single page. Fixed a (not very likely encountered) bug in fetchdecode.cc (and fetchdecode64.cc) where a 2-byte opcode starting with a prefix starts at the last offset on a page. There were no checks on the segment overrides for a boundary condition. I added them. The eflags enhancements added just a tiny bit of performance.
187 lines
4.6 KiB
C++
187 lines
4.6 KiB
C++
/////////////////////////////////////////////////////////////////////////
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// $Id: flag_ctrl_pro.cc,v 1.10 2002-09-22 18:22:24 kevinlawton Exp $
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/////////////////////////////////////////////////////////////////////////
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//
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// Copyright (C) 2001 MandrakeSoft S.A.
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//
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// MandrakeSoft S.A.
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// 43, rue d'Aboukir
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// 75002 Paris - France
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// http://www.linux-mandrake.com/
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// http://www.mandrakesoft.com/
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//
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// This library is free software; you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public
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// License as published by the Free Software Foundation; either
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// version 2 of the License, or (at your option) any later version.
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//
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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// Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public
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// License along with this library; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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#define NEED_CPU_REG_SHORTCUTS 1
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#include "bochs.h"
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#define LOG_THIS BX_CPU_THIS_PTR
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void
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BX_CPU_C::write_flags(Bit16u flags, Boolean change_IOPL, Boolean change_IF)
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{
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Bit32u changeMask; // Really should be passed in.
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changeMask = 0x0dd5;
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#if BX_CPU_LEVEL <= 2
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// NT = 0
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#else
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changeMask |= (1<<14); // NT is modified as requested.
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#endif
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#if BX_CPU_LEVEL >= 3
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if (change_IOPL)
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changeMask |= (3<<12); // IOPL is modified as requested.
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#else
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// IOPL = 0
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#endif
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if (change_IF)
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changeMask |= (1<<9);
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BX_CPU_THIS_PTR setEFlags(
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(BX_CPU_THIS_PTR eflags.val32 & ~changeMask) | (flags & changeMask) );
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BX_CPU_THIS_PTR lf_flags_status = 0; // OSZAPC flags are known.
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#if 0
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// +++
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if (get_TF ()==0 && (flags&0x0100))
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BX_DEBUG(( "TF 0->1" ));
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else if (get_TF () && !(flags&0x0100))
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BX_DEBUG(( "TF 1->0" ));
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else if (get_TF () && (flags&0x0100))
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BX_DEBUG(( "TF 1->1" ));
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#endif
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if ( flags & (1 << 8) ) {
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BX_CPU_THIS_PTR async_event = 1; // TF = 1
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}
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}
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#if BX_CPU_LEVEL >= 3
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void
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BX_CPU_C::write_eflags(Bit32u eflags_raw, Boolean change_IOPL, Boolean change_IF,
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Boolean change_VM, Boolean change_RF)
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{
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Bit32u changeMask; // Really should be passed in.
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changeMask = 0x4dd5;
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#if BX_CPU_LEVEL >= 4
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changeMask |= ((1<<21) | (1<<18)); // ID/AC
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#endif
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if (change_IOPL)
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changeMask |= (3<<12);
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if (change_IF)
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changeMask |= (1<<9);
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if (change_VM) {
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changeMask |= (1<<17);
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#if BX_SUPPORT_V8086_MODE == 0
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if ( eflags_raw & (1<<17) )
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BX_PANIC(("write_eflags: VM bit set: BX_SUPPORT_V8086_MODE==0"));
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#endif
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}
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if (change_RF)
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changeMask |= (1<<16);
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BX_CPU_THIS_PTR setEFlags(
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(BX_CPU_THIS_PTR eflags.val32 & ~changeMask) | (eflags_raw & changeMask) );
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BX_CPU_THIS_PTR lf_flags_status = 0; // OSZAPC flags are known.
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#if 0
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// +++
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if (get_TF ()==0 && (eflags_raw&0x0100))
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BX_DEBUG(( "TF 0->1" ));
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else if (get_TF () && !(eflags_raw&0x0100))
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BX_DEBUG(( "TF 1->0" ));
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else if (get_TF () && (eflags_raw&0x0100))
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BX_DEBUG(( "TF 1->1" ));
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#endif
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if (eflags_raw & (1 << 8)) {
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BX_CPU_THIS_PTR async_event = 1; // TF = 1
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}
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}
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#endif /* BX_CPU_LEVEL >= 3 */
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Bit16u
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BX_CPU_C::read_flags(void)
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{
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Bit16u flags16;
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// Cause arithmetic flags to be in known state and cached in val32.
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if (BX_CPU_THIS_PTR lf_flags_status) {
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(void) get_CF();
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(void) get_PF();
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(void) get_AF();
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(void) get_ZF();
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(void) get_SF();
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(void) get_OF();
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}
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flags16 = (Bit16u) BX_CPU_THIS_PTR eflags.val32;
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/* 8086: bits 12-15 always set to 1.
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* 286: in real mode, bits 12-15 always cleared.
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* 386+: real-mode: bit15 cleared, bits 14..12 are last loaded value
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* protected-mode: bit 15 clear, bit 14 = last loaded, IOPL?
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*/
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#if BX_CPU_LEVEL < 2
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flags16 |= 0xF000; /* 8086 nature */
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#elif BX_CPU_LEVEL == 2
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if (real_mode()) {
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flags16 &= 0x0FFF; /* 80286 in real mode nature */
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}
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#else /* 386+ */
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#endif
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return(flags16);
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}
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#if BX_CPU_LEVEL >= 3
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Bit32u
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BX_CPU_C::read_eflags(void)
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{
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Bit32u flags32;
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// Cause arithmetic flags to be in known state and cached in val32.
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if (BX_CPU_THIS_PTR lf_flags_status) {
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(void) get_CF();
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(void) get_PF();
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(void) get_AF();
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(void) get_ZF();
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(void) get_SF();
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(void) get_OF();
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}
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flags32 = BX_CPU_THIS_PTR eflags.val32;
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#if 0
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/*
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* 386+: real-mode: bit15 cleared, bits 14..12 are last loaded value
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* protected-mode: bit 15 clear, bit 14 = last loaded, IOPL?
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*/
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#endif
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return(flags32);
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}
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#endif /* BX_CPU_LEVEL >= 3 */
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