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Bochs/bochs/fpu/fpu_compare.cc
Stanislav Shwartsman 002c86660a reword all the CPU code in preparation for future CPU speedup implementation. 
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
2011-07-06 20:01:18 +00:00

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/////////////////////////////////////////////////////////////////////////
// $Id$
/////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2003-2009 Stanislav Shwartsman
// Written by Stanislav Shwartsman [sshwarts at sourceforge net]
//
// 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
//
/////////////////////////////////////////////////////////////////////////
#define NEED_CPU_REG_SHORTCUTS 1
#include "bochs.h"
#include "cpu/cpu.h"
#define LOG_THIS BX_CPU_THIS_PTR
#if BX_SUPPORT_FPU
extern float_status_t FPU_pre_exception_handling(Bit16u control_word);
#include "softfloatx80.h"
static int status_word_flags_fpu_compare(int float_relation)
{
switch(float_relation) {
case float_relation_unordered:
return (FPU_SW_C0|FPU_SW_C2|FPU_SW_C3);
case float_relation_greater:
return (0);
case float_relation_less:
return (FPU_SW_C0);
case float_relation_equal:
return (FPU_SW_C3);
}
return (-1); // should never get here
}
void BX_CPU_C::write_eflags_fpu_compare(int float_relation)
{
switch(float_relation) {
case float_relation_unordered:
setEFlagsOSZAPC(EFlagsZFMask | EFlagsPFMask | EFlagsCFMask);
break;
case float_relation_greater:
setEFlagsOSZAPC(0);
break;
case float_relation_less:
setEFlagsOSZAPC(EFlagsCFMask);
break;
case float_relation_equal:
setEFlagsOSZAPC(EFlagsZFMask);
break;
default:
BX_PANIC(("write_eflags: unknown floating point compare relation"));
}
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::FCOM_STi(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
int pop_stack = i->nnn() & 1;
// handle special case of FSTP opcode @ 0xDE 0xD0..D7
if (i->b1() == 0xde)
pop_stack = 1;
clear_C1();
if (IS_TAG_EMPTY(0) || IS_TAG_EMPTY(i->rm()))
{
FPU_exception(FPU_EX_Stack_Underflow);
setcc(FPU_SW_C0|FPU_SW_C2|FPU_SW_C3);
if(BX_CPU_THIS_PTR the_i387.is_IA_masked())
{
if (pop_stack)
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
float_status_t status =
FPU_pre_exception_handling(BX_CPU_THIS_PTR the_i387.get_control_word());
int rc = floatx80_compare(BX_READ_FPU_REG(0), BX_READ_FPU_REG(i->rm()), status);
setcc(status_word_flags_fpu_compare(rc));
if (! FPU_exception(status.float_exception_flags)) {
if (pop_stack)
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::FCOMI_ST0_STj(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
int pop_stack = i->b1() & 4;
clear_C1();
if (IS_TAG_EMPTY(0) || IS_TAG_EMPTY(i->rm()))
{
FPU_exception(FPU_EX_Stack_Underflow);
setEFlagsOSZAPC(EFlagsZFMask | EFlagsPFMask | EFlagsCFMask);
if(BX_CPU_THIS_PTR the_i387.is_IA_masked())
{
if (pop_stack)
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
float_status_t status =
FPU_pre_exception_handling(BX_CPU_THIS_PTR the_i387.get_control_word());
int rc = floatx80_compare(BX_READ_FPU_REG(0), BX_READ_FPU_REG(i->rm()), status);
BX_CPU_THIS_PTR write_eflags_fpu_compare(rc);
if (! FPU_exception(status.float_exception_flags)) {
if (pop_stack)
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::FUCOMI_ST0_STj(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
int pop_stack = i->b1() & 4;
clear_C1();
if (IS_TAG_EMPTY(0) || IS_TAG_EMPTY(i->rm()))
{
FPU_exception(FPU_EX_Stack_Underflow);
setEFlagsOSZAPC(EFlagsZFMask | EFlagsPFMask | EFlagsCFMask);
if(BX_CPU_THIS_PTR the_i387.is_IA_masked())
{
if (pop_stack)
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
float_status_t status =
FPU_pre_exception_handling(BX_CPU_THIS_PTR the_i387.get_control_word());
int rc = floatx80_compare_quiet(BX_READ_FPU_REG(0), BX_READ_FPU_REG(i->rm()), status);
BX_CPU_THIS_PTR write_eflags_fpu_compare(rc);
if (! FPU_exception(status.float_exception_flags)) {
if (pop_stack)
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::FUCOM_STi(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
int pop_stack = i->nnn() & 1;
if (IS_TAG_EMPTY(0) || IS_TAG_EMPTY(i->rm()))
{
FPU_exception(FPU_EX_Stack_Underflow);
setcc(FPU_SW_C0|FPU_SW_C2|FPU_SW_C3);
if(BX_CPU_THIS_PTR the_i387.is_IA_masked())
{
if (pop_stack)
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
float_status_t status =
FPU_pre_exception_handling(BX_CPU_THIS_PTR the_i387.get_control_word());
int rc = floatx80_compare_quiet(BX_READ_FPU_REG(0), BX_READ_FPU_REG(i->rm()), status);
setcc(status_word_flags_fpu_compare(rc));
if (! FPU_exception(status.float_exception_flags)) {
if (pop_stack)
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::FCOM_SINGLE_REAL(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
int pop_stack = i->nnn() & 1, rc;
RMAddr(i) = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
float32 load_reg = read_virtual_dword(i->seg(), RMAddr(i));
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
clear_C1();
if (IS_TAG_EMPTY(0))
{
FPU_exception(FPU_EX_Stack_Underflow);
setcc(FPU_SW_C0|FPU_SW_C2|FPU_SW_C3);
if(BX_CPU_THIS_PTR the_i387.is_IA_masked())
{
if (pop_stack)
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
float_status_t status =
FPU_pre_exception_handling(BX_CPU_THIS_PTR the_i387.get_control_word());
floatx80 a = BX_READ_FPU_REG(0);
if (floatx80_is_nan(a) || floatx80_is_unsupported(a) || float32_is_nan(load_reg)) {
rc = float_relation_unordered;
float_raise(status, float_flag_invalid);
}
else {
rc = floatx80_compare(a, float32_to_floatx80(load_reg, status), status);
}
setcc(status_word_flags_fpu_compare(rc));
if (! FPU_exception(status.float_exception_flags)) {
if (pop_stack)
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::FCOM_DOUBLE_REAL(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
int pop_stack = i->nnn() & 1, rc;
RMAddr(i) = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
float64 load_reg = read_virtual_qword(i->seg(), RMAddr(i));
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
clear_C1();
if (IS_TAG_EMPTY(0))
{
FPU_exception(FPU_EX_Stack_Underflow);
setcc(FPU_SW_C0|FPU_SW_C2|FPU_SW_C3);
if(BX_CPU_THIS_PTR the_i387.is_IA_masked())
{
if (pop_stack)
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
float_status_t status =
FPU_pre_exception_handling(BX_CPU_THIS_PTR the_i387.get_control_word());
floatx80 a = BX_READ_FPU_REG(0);
if (floatx80_is_nan(a) || floatx80_is_unsupported(a) || float64_is_nan(load_reg)) {
rc = float_relation_unordered;
float_raise(status, float_flag_invalid);
}
else {
rc = floatx80_compare(a, float64_to_floatx80(load_reg, status), status);
}
setcc(status_word_flags_fpu_compare(rc));
if (! FPU_exception(status.float_exception_flags)) {
if (pop_stack)
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::FICOM_WORD_INTEGER(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
int pop_stack = i->nnn() & 1;
RMAddr(i) = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
Bit16s load_reg = (Bit16s) read_virtual_word(i->seg(), RMAddr(i));
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
clear_C1();
if (IS_TAG_EMPTY(0))
{
FPU_exception(FPU_EX_Stack_Underflow);
setcc(FPU_SW_C0|FPU_SW_C2|FPU_SW_C3);
if(BX_CPU_THIS_PTR the_i387.is_IA_masked())
{
if (pop_stack)
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
float_status_t status =
FPU_pre_exception_handling(BX_CPU_THIS_PTR the_i387.get_control_word());
int rc = floatx80_compare(BX_READ_FPU_REG(0),
int32_to_floatx80((Bit32s)(load_reg)), status);
setcc(status_word_flags_fpu_compare(rc));
if (! FPU_exception(status.float_exception_flags)) {
if (pop_stack)
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::FICOM_DWORD_INTEGER(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
int pop_stack = i->nnn() & 1;
RMAddr(i) = BX_CPU_CALL_METHODR(i->ResolveModrm, (i));
Bit32s load_reg = (Bit32s) read_virtual_dword(i->seg(), RMAddr(i));
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
clear_C1();
if (IS_TAG_EMPTY(0))
{
FPU_exception(FPU_EX_Stack_Underflow);
setcc(FPU_SW_C0|FPU_SW_C2|FPU_SW_C3);
if(BX_CPU_THIS_PTR the_i387.is_IA_masked())
{
if (pop_stack)
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
float_status_t status =
FPU_pre_exception_handling(BX_CPU_THIS_PTR the_i387.get_control_word());
int rc = floatx80_compare(BX_READ_FPU_REG(0), int32_to_floatx80(load_reg), status);
setcc(status_word_flags_fpu_compare(rc));
if (! FPU_exception(status.float_exception_flags)) {
if (pop_stack)
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
/* DE D9 */
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::FCOMPP(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
clear_C1();
if (IS_TAG_EMPTY(0) || IS_TAG_EMPTY(1))
{
FPU_exception(FPU_EX_Stack_Underflow);
setcc(FPU_SW_C0|FPU_SW_C2|FPU_SW_C3);
if(BX_CPU_THIS_PTR the_i387.is_IA_masked())
{
BX_CPU_THIS_PTR the_i387.FPU_pop();
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
float_status_t status =
FPU_pre_exception_handling(BX_CPU_THIS_PTR the_i387.get_control_word());
int rc = floatx80_compare(BX_READ_FPU_REG(0), BX_READ_FPU_REG(1), status);
setcc(status_word_flags_fpu_compare(rc));
if (! FPU_exception(status.float_exception_flags)) {
BX_CPU_THIS_PTR the_i387.FPU_pop();
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
/* DA E9 */
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::FUCOMPP(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
if (IS_TAG_EMPTY(0) || IS_TAG_EMPTY(1))
{
FPU_exception(FPU_EX_Stack_Underflow);
setcc(FPU_SW_C0|FPU_SW_C2|FPU_SW_C3);
if(BX_CPU_THIS_PTR the_i387.is_IA_masked())
{
BX_CPU_THIS_PTR the_i387.FPU_pop();
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
float_status_t status =
FPU_pre_exception_handling(BX_CPU_THIS_PTR the_i387.get_control_word());
int rc = floatx80_compare_quiet(BX_READ_FPU_REG(0), BX_READ_FPU_REG(1), status);
setcc(status_word_flags_fpu_compare(rc));
if (! FPU_exception(status.float_exception_flags)) {
BX_CPU_THIS_PTR the_i387.FPU_pop();
BX_CPU_THIS_PTR the_i387.FPU_pop();
}
BX_NEXT_INSTR(i);
}
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::FCMOV_ST0_STj(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
if (IS_TAG_EMPTY(0) || IS_TAG_EMPTY(i->rm()))
{
FPU_stack_underflow(0);
BX_NEXT_INSTR(i);
}
floatx80 sti_reg = BX_READ_FPU_REG(i->rm());
bx_bool condition = 0;
switch(i->nnn() & 3)
{
case 0: condition = get_CF(); break;
case 1: condition = get_ZF(); break;
case 2: condition = get_CF() || get_ZF(); break;
case 3: condition = get_PF(); break;
default:
BX_PANIC(("FCMOV_ST0_STj: default case"));
}
if (i->b1() & 1)
condition = !condition;
if (condition)
BX_WRITE_FPU_REG(sti_reg, 0);
BX_NEXT_INSTR(i);
}
/* D9 E4 */
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::FTST(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
clear_C1();
if (IS_TAG_EMPTY(0)) {
FPU_exception(FPU_EX_Stack_Underflow);
setcc(FPU_SW_C0|FPU_SW_C2|FPU_SW_C3);
}
else {
extern const floatx80 Const_Z;
float_status_t status =
FPU_pre_exception_handling(BX_CPU_THIS_PTR the_i387.get_control_word());
int rc = floatx80_compare(BX_READ_FPU_REG(0), Const_Z, status);
setcc(status_word_flags_fpu_compare(rc));
FPU_exception(status.float_exception_flags);
}
BX_NEXT_INSTR(i);
}
/* D9 E5 */
BX_INSF_TYPE BX_CPP_AttrRegparmN(1) BX_CPU_C::FXAM(bxInstruction_c *i)
{
BX_CPU_THIS_PTR prepareFPU(i);
BX_CPU_THIS_PTR FPU_update_last_instruction(i);
floatx80 reg = BX_READ_FPU_REG(0);
int sign = floatx80_sign(reg);
/*
* Examine the contents of the ST(0) register and sets the condition
* code flags C0, C2 and C3 in the FPU status word to indicate the
* class of value or number in the register.
*/
if (IS_TAG_EMPTY(0))
{
setcc(FPU_SW_C3|FPU_SW_C1|FPU_SW_C0);
}
else
{
float_class_t aClass = floatx80_class(reg);
switch(aClass)
{
case float_zero:
setcc(FPU_SW_C3|FPU_SW_C1);
break;
case float_NaN:
// unsupported handled as NaNs
if (floatx80_is_unsupported(reg)) {
setcc(FPU_SW_C1);
} else {
setcc(FPU_SW_C1|FPU_SW_C0);
}
break;
case float_negative_inf:
case float_positive_inf:
setcc(FPU_SW_C2|FPU_SW_C1|FPU_SW_C0);
break;
case float_denormal:
setcc(FPU_SW_C3|FPU_SW_C2|FPU_SW_C1);
break;
case float_normalized:
setcc(FPU_SW_C2|FPU_SW_C1);
break;
}
}
/*
* The C1 flag is set to the sign of the value in ST(0), regardless
* of whether the register is empty or full.
*/
if (! sign)
clear_C1();
BX_NEXT_INSTR(i);
}
#endif
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