002c86660a
Bochs emulation can be another 10-15% faster using technique described in paper "Fast Microcode Interpretation with Transactional Commit/Abort" http://amas-bt.cs.virginia.edu/2011proceedings/amasbt2011-p3.pdf
126 lines
3.2 KiB
C++
126 lines
3.2 KiB
C++
/////////////////////////////////////////////////////////////////////////
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// $Id$
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/////////////////////////////////////////////////////////////////////////
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//
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// Copyright (C) 2001-2011 The Bochs Project
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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., 51 Franklin St, Fifth Floor, Boston, MA B 02110-1301 USA
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/////////////////////////////////////////////////////////////////////////
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#define NEED_CPU_REG_SHORTCUTS 1
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#include "bochs.h"
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#include "cpu.h"
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#define LOG_THIS BX_CPU_THIS_PTR
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BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::MUL_ALEbR(bxInstruction_c *i)
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{
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Bit8u op1 = AL;
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Bit8u op2 = BX_READ_8BIT_REGx(i->rm(), i->extend8bitL());
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Bit32u product_16 = ((Bit16u) op1) * ((Bit16u) op2);
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Bit8u product_8l = (product_16 & 0xFF);
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Bit8u product_8h = product_16 >> 8;
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/* now write product back to destination */
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AX = product_16;
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/* set EFLAGS */
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SET_FLAGS_OSZAPC_LOGIC_8(product_8l);
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if(product_8h != 0)
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{
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ASSERT_FLAGS_OxxxxC();
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}
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BX_NEXT_INSTR(i);
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}
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BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::IMUL_ALEbR(bxInstruction_c *i)
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{
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Bit8s op1 = AL;
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Bit8s op2 = BX_READ_8BIT_REGx(i->rm(), i->extend8bitL());
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Bit16s product_16 = op1 * op2;
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Bit8u product_8 = (product_16 & 0xFF);
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/* now write product back to destination */
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AX = product_16;
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/* set EFLAGS:
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* IMUL r/m8: condition for clearing CF & OF:
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* AX = sign-extend of AL to 16 bits
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*/
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SET_FLAGS_OSZAPC_LOGIC_8(product_8);
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if(product_16 != (Bit8s) product_16)
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{
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ASSERT_FLAGS_OxxxxC();
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}
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BX_NEXT_INSTR(i);
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}
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BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::DIV_ALEbR(bxInstruction_c *i)
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{
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Bit8u op2 = BX_READ_8BIT_REGx(i->rm(), i->extend8bitL());
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if (op2 == 0) {
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exception(BX_DE_EXCEPTION, 0);
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}
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Bit16u op1 = AX;
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Bit16u quotient_16 = op1 / op2;
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Bit8u remainder_8 = op1 % op2;
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Bit8u quotient_8l = quotient_16 & 0xFF;
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if (quotient_16 != quotient_8l)
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{
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exception(BX_DE_EXCEPTION, 0);
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}
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/* now write quotient back to destination */
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AL = quotient_8l;
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AH = remainder_8;
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BX_NEXT_INSTR(i);
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}
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BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::IDIV_ALEbR(bxInstruction_c *i)
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{
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Bit16s op1 = AX;
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/* check MIN_INT case */
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if (op1 == ((Bit16s)0x8000))
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exception(BX_DE_EXCEPTION, 0);
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Bit8s op2 = BX_READ_8BIT_REGx(i->rm(), i->extend8bitL());
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if (op2 == 0)
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exception(BX_DE_EXCEPTION, 0);
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Bit16s quotient_16 = op1 / op2;
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Bit8s remainder_8 = op1 % op2;
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Bit8s quotient_8l = quotient_16 & 0xFF;
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if (quotient_16 != quotient_8l)
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exception(BX_DE_EXCEPTION, 0);
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/* now write quotient back to destination */
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AL = quotient_8l;
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AH = remainder_8;
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BX_NEXT_INSTR(i);
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}
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