468 lines
10 KiB
C++
468 lines
10 KiB
C++
/////////////////////////////////////////////////////////////////////////
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// $Id: shift16.cc,v 1.28 2005-10-13 20:21:35 sshwarts 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 BX_CPU_C::SHLD_EwGw(bxInstruction_c *i)
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{
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Bit16u op1_16, op2_16, result_16;
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Bit32u temp_32, result_32;
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unsigned count;
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/* op1:op2 << count. result stored in op1 */
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if (i->b1() == 0x1a4)
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count = i->Ib();
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else // 0x1a5
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count = CL;
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count &= 0x1f; // use only 5 LSB's
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/* op1 is a register or memory reference */
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if (i->modC0()) {
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op1_16 = BX_READ_16BIT_REG(i->rm());
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}
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else {
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/* pointer, segment address pair */
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read_RMW_virtual_word(i->seg(), RMAddr(i), &op1_16);
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}
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if (!count) return;
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// count is 1..31
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op2_16 = BX_READ_16BIT_REG(i->nnn());
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temp_32 = ((Bit32u)(op1_16) << 16) | (op2_16); // double formed by op1:op2
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result_32 = temp_32 << count;
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// Hack to act like x86 SHLD when count > 16
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if (count > 16) {
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// when count > 16 actually shifting op1:op2:op2 << count,
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// it is the same as shifting op2:op2 by count-16
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result_32 |= (op1_16 << (count - 16));
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}
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result_16 = result_32 >> 16;
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/* now write result back to destination */
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if (i->modC0()) {
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BX_WRITE_16BIT_REG(i->rm(), result_16);
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}
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else {
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Write_RMW_virtual_word(result_16);
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}
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/* set eflags:
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* SHLD count affects the following flags: O,S,Z,A,P,C
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*/
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SET_FLAGS_OSZAPC_16(op1_16, count, result_16, BX_INSTR_SHL16);
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}
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void BX_CPU_C::SHRD_EwGw(bxInstruction_c *i)
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{
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Bit16u op1_16, op2_16, result_16;
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Bit32u temp_32, result_32;
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unsigned count;
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if (i->b1() == 0x1ac)
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count = i->Ib();
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else // 0x1ad
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count = CL;
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count &= 0x1f; /* use only 5 LSB's */
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/* op1 is a register or memory reference */
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if (i->modC0()) {
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op1_16 = BX_READ_16BIT_REG(i->rm());
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}
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else {
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/* pointer, segment address pair */
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read_RMW_virtual_word(i->seg(), RMAddr(i), &op1_16);
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}
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if (!count) return;
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// count is 1..31
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op2_16 = BX_READ_16BIT_REG(i->nnn());
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// Hack to act like x86 SHLD when count > 16
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temp_32 = (op2_16 << 16) | op1_16; // double formed by op2:op1
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result_32 = temp_32 >> count;
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if (count > 16) {
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// when count > 16 actually shifting op2:op2:op1 >> count,
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// it is the same as shifting op2:op2 by count-16
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result_32 |= (op1_16 << (32 - count));
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}
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result_16 = result_32;
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/* now write result back to destination */
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if (i->modC0()) {
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BX_WRITE_16BIT_REG(i->rm(), result_16);
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}
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else {
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Write_RMW_virtual_word(result_16);
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}
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/* set eflags:
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* SHRD count affects the following flags: O,S,Z,A,P,C
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*/
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SET_FLAGS_OSZAPC_16(op1_16, count, result_16, BX_INSTR_SHRD16);
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}
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void BX_CPU_C::ROL_Ew(bxInstruction_c *i)
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{
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Bit16u op1_16, result_16;
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unsigned count;
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if ( i->b1() == 0xc1 )
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count = i->Ib();
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else if ( i->b1() == 0xd1 )
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count = 1;
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else // 0xd3
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count = CL;
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/* op1 is a register or memory reference */
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if (i->modC0()) {
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op1_16 = BX_READ_16BIT_REG(i->rm());
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}
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else {
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/* pointer, segment address pair */
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read_RMW_virtual_word(i->seg(), RMAddr(i), &op1_16);
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}
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if ( (count & 0x0f) == 0 ) {
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if ( count & 0x10 ) {
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unsigned bit0 = op1_16 & 1;
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set_CF(bit0);
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}
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return;
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}
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count &= 0x0f; // only use bottom 4 bits
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result_16 = (op1_16 << count) | (op1_16 >> (16 - count));
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/* now write result back to destination */
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if (i->modC0()) {
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BX_WRITE_16BIT_REG(i->rm(), result_16);
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}
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else {
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Write_RMW_virtual_word(result_16);
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}
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/* set eflags:
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* ROL count affects the following flags: C, O
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*/
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bx_bool temp_CF = (result_16 & 0x01);
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set_CF(temp_CF);
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set_OF(temp_CF ^ (result_16 >> 15));
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}
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void BX_CPU_C::ROR_Ew(bxInstruction_c *i)
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{
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Bit16u op1_16, result_16;
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unsigned count;
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if ( i->b1() == 0xc1 )
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count = i->Ib();
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else if ( i->b1() == 0xd1 )
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count = 1;
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else // 0xd3
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count = CL;
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/* op1 is a register or memory reference */
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if (i->modC0()) {
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op1_16 = BX_READ_16BIT_REG(i->rm());
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}
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else {
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/* pointer, segment address pair */
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read_RMW_virtual_word(i->seg(), RMAddr(i), &op1_16);
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}
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if ( (count & 0x0f) == 0 ) {
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if ( count & 0x10 ) {
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unsigned MSB = op1_16 >> 15;
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set_CF(MSB);
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}
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return;
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}
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count &= 0x0f; // use only 4 LSB's
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result_16 = (op1_16 >> count) | (op1_16 << (16 - count));
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/* now write result back to destination */
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if (i->modC0()) {
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BX_WRITE_16BIT_REG(i->rm(), result_16);
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}
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else {
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Write_RMW_virtual_word(result_16);
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}
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/* set eflags:
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* ROR count affects the following flags: C, O
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*/
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bx_bool result_b15 = (result_16 & 0x8000) != 0;
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bx_bool result_b14 = (result_16 & 0x4000) != 0;
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set_CF(result_b15);
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set_OF(result_b15 ^ result_b14);
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}
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void BX_CPU_C::RCL_Ew(bxInstruction_c *i)
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{
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Bit16u op1_16, result_16;
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unsigned count;
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if ( i->b1() == 0xc1 )
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count = i->Ib();
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else if ( i->b1() == 0xd1 )
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count = 1;
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else // 0xd3
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count = CL;
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count = (count & 0x1f) % 17;
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/* op1 is a register or memory reference */
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if (i->modC0()) {
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op1_16 = BX_READ_16BIT_REG(i->rm());
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}
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else {
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/* pointer, segment address pair */
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read_RMW_virtual_word(i->seg(), RMAddr(i), &op1_16);
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}
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if (!count) return;
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if (count==1) {
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result_16 = (op1_16 << 1) | getB_CF();
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}
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else if (count==16) {
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result_16 = (getB_CF() << 15) | (op1_16 >> 1);
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}
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else { // 2..15
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result_16 = (op1_16 << count) | (getB_CF() << (count - 1)) |
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(op1_16 >> (17 - count));
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}
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/* now write result back to destination */
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if (i->modC0()) {
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BX_WRITE_16BIT_REG(i->rm(), result_16);
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}
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else {
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Write_RMW_virtual_word(result_16);
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}
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/* set eflags:
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* RCL count affects the following flags: C, O
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*/
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bx_bool temp_CF = (op1_16 >> (16 - count)) & 0x01;
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set_CF(temp_CF);
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set_OF(temp_CF ^ (result_16 >> 15));
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}
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void BX_CPU_C::RCR_Ew(bxInstruction_c *i)
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{
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Bit16u op1_16, result_16;
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unsigned count;
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if ( i->b1() == 0xc1 )
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count = i->Ib();
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else if ( i->b1() == 0xd1 )
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count = 1;
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else // 0xd3
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count = CL;
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count = (count & 0x1f) % 17;
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/* op1 is a register or memory reference */
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if (i->modC0()) {
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op1_16 = BX_READ_16BIT_REG(i->rm());
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}
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else {
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/* pointer, segment address pair */
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read_RMW_virtual_word(i->seg(), RMAddr(i), &op1_16);
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}
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if (! count) return;
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result_16 = (op1_16 >> count) |
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(getB_CF() << (16 - count)) |
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(op1_16 << (17 - count));
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/* now write result back to destination */
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if (i->modC0()) {
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BX_WRITE_16BIT_REG(i->rm(), result_16);
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}
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else {
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Write_RMW_virtual_word(result_16);
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}
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/* set eflags:
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* RCR count affects the following flags: C, O
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*/
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set_CF((op1_16 >> (count - 1)) & 0x01);
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set_OF((((result_16 << 1) ^ result_16) & 0x8000) > 0);
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}
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void BX_CPU_C::SHL_Ew(bxInstruction_c *i)
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{
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Bit16u op1_16, result_16;
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unsigned count;
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if ( i->b1() == 0xc1 )
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count = i->Ib();
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else if ( i->b1() == 0xd1 )
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count = 1;
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else // 0xd3
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count = CL;
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count &= 0x1f; /* use only 5 LSB's */
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/* op1 is a register or memory reference */
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if (i->modC0()) {
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op1_16 = BX_READ_16BIT_REG(i->rm());
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}
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else {
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/* pointer, segment address pair */
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read_RMW_virtual_word(i->seg(), RMAddr(i), &op1_16);
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}
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if (!count) return;
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result_16 = (op1_16 << count);
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/* now write result back to destination */
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if (i->modC0()) {
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BX_WRITE_16BIT_REG(i->rm(), result_16);
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}
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else {
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Write_RMW_virtual_word(result_16);
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}
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SET_FLAGS_OSZAPC_16(op1_16, count, result_16, BX_INSTR_SHL16);
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}
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void BX_CPU_C::SHR_Ew(bxInstruction_c *i)
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{
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Bit16u op1_16, result_16;
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unsigned count;
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if ( i->b1() == 0xc1 )
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count = i->Ib();
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else if ( i->b1() == 0xd1 )
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count = 1;
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else // 0xd3
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count = CL;
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count &= 0x1f; /* use only 5 LSB's */
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/* op1 is a register or memory reference */
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if (i->modC0()) {
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op1_16 = BX_READ_16BIT_REG(i->rm());
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}
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else {
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/* pointer, segment address pair */
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read_RMW_virtual_word(i->seg(), RMAddr(i), &op1_16);
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}
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if (!count) return;
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#if defined(BX_HostAsm_Shr16)
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Bit32u flags32;
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asmShr16(result_16, op1_16, count, flags32);
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setEFlagsOSZAPC(flags32);
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#else
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result_16 = (op1_16 >> count);
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SET_FLAGS_OSZAPC_16(op1_16, count, result_16, BX_INSTR_SHR16);
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#endif
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/* now write result back to destination */
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if (i->modC0()) {
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BX_WRITE_16BIT_REG(i->rm(), result_16);
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}
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else {
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Write_RMW_virtual_word(result_16);
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}
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}
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void BX_CPU_C::SAR_Ew(bxInstruction_c *i)
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{
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Bit16u op1_16, result_16;
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unsigned count;
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if ( i->b1() == 0xc1 )
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count = i->Ib();
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else if ( i->b1() == 0xd1 )
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count = 1;
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else // 0xd3
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count = CL;
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count &= 0x1f; /* use only 5 LSB's */
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/* op1 is a register or memory reference */
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if (i->modC0()) {
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op1_16 = BX_READ_16BIT_REG(i->rm());
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}
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else {
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/* pointer, segment address pair */
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read_RMW_virtual_word(i->seg(), RMAddr(i), &op1_16);
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}
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if (!count) return;
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if (count < 16) {
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if (op1_16 & 0x8000) {
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result_16 = (op1_16 >> count) | (0xffff << (16 - count));
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}
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else {
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result_16 = (op1_16 >> count);
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}
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}
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else {
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if (op1_16 & 0x8000) {
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result_16 = 0xffff;
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}
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else {
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result_16 = 0;
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}
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}
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/* now write result back to destination */
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if (i->modC0()) {
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BX_WRITE_16BIT_REG(i->rm(), result_16);
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}
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else {
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Write_RMW_virtual_word(result_16);
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}
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SET_FLAGS_OSZAPC_16(op1_16, count, result_16, BX_INSTR_SAR16);
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}
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