mirrors/Bochs
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fixed BCD instructions to be suitable with Intel docs

Browse Source
This commit is contained in:
Stanislav Shwartsman 2004-03-09 20:45:17 +00:00
parent 2243d9a612
commit 8484a03394
1 changed files with 59 additions and 55 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

114
bochs/cpu/bcd.cc
View File

@ -1,5 +1,5 @@
/////////////////////////////////////////////////////////////////////////
// $Id: bcd.cc,v 1.7 2002-09-17 22:50:51 kevinlawton Exp $
// $Id: bcd.cc,v 1.8 2004-03-09 20:45:17 sshwarts Exp $
/////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2002 MandrakeSoft S.A.
@ -38,9 +38,6 @@
void
BX_CPU_C::DAS(bxInstruction_c *)
{
Bit8u tmpCF, tmpAL;
/* ??? */
/* the algorithm for DAS is fashioned after the pseudo code in the
* Pentium Processor Family Developer's Manual, volume 3. It seems
* to have changed from earlier processor's manuals. I'm not sure
@ -49,69 +46,74 @@ BX_CPU_C::DAS(bxInstruction_c *)
* correct yet...
*/
tmpCF = 0;
tmpAL = AL;
Bit8u tmpAL = AL;
int tmpCF = 0;
/* DAS effect the following flags: A,C,S,Z,P */
if (((tmpAL & 0x0F) > 0x09) || get_AF()) {
if (((AL & 0x0F) > 0x09) || get_AF())
{
tmpAL = AL - 0x06;
if ((AL < 0x06) || get_CF()) tmpCF = 1;
set_AF(1);
tmpCF = (AL < 0x06) || get_CF();
AL = AL - 0x06;
/*tmpCF = (AL < 0) || CF;*/
}
if ( (tmpAL > 0x99) || get_CF() ) {
}
else
set_AF(0);
if ((AL > 0x99) || get_CF())
{
AL = AL - 0x60;
tmpCF = 1;
}
}
else
tmpCF = 0;
AL = tmpAL;
set_CF(tmpCF);
set_SF(AL >> 7);
set_ZF(AL==0);
set_PF_base(AL);
set_SF(tmpAL >> 7);
set_ZF(tmpAL==0);
set_PF_base(tmpAL);
}
void
BX_CPU_C::AAA(bxInstruction_c *)
{
Bit8u ALcarry;
/* AAA affects the following flags: A,C */
ALcarry = AL > 0xf9;
/* AAA effects the following flags: A,C */
if ( ((AL & 0x0f) > 9) || get_AF() ) {
AL = (AL + 6) & 0x0f;
AH = AH + 1 + ALcarry;
if ( ((AL & 0x0f) > 9) || get_AF() )
{
AL = AL + 6;
AH = AH + 1;
set_AF(1);
set_CF(1);
}
}
else {
set_AF(0);
set_CF(0);
AL = AL & 0x0f;
}
}
AL = AL & 0x0f;
}
void
BX_CPU_C::AAS(bxInstruction_c *)
{
Bit8u ALborrow;
/* AAS affects the following flags: A,C */
ALborrow = AL < 6;
if ( ((AL & 0x0F) > 0x09) || get_AF() ) {
AL = (AL - 6) & 0x0f;
AH = AH - 1 - ALborrow;
if ( ((AL & 0x0F) > 0x09) || get_AF() )
{
AL = AL - 6;
AH = AH - 1;
set_AF(1);
set_CF(1);
}
}
else {
set_CF(0);
set_AF(0);
AL = AL & 0x0f;
}
}
AL = AL & 0x0f;
}
void
@ -121,9 +123,8 @@ BX_CPU_C::AAM(bxInstruction_c *i)
imm8 = i->Ib();
if (imm8 == 0) {
if (imm8 == 0)
exception(BX_DE_EXCEPTION, 0, 0);
}
al = AL;
AH = al / imm8;
@ -132,6 +133,7 @@ BX_CPU_C::AAM(bxInstruction_c *i)
/* AAM always clears the flags A and C */
set_AF(0);
set_CF(0);
/* AAM affects the following flags: S,Z,P */
set_SF((AL & 0x80) > 0);
set_ZF(AL == 0);
@ -149,7 +151,7 @@ BX_CPU_C::AAD(bxInstruction_c *i)
ax1 = AH * imm8;
ax2 = ax1 + AL;
al = AL;
AL = (Bit8u)ax2;
AL = (Bit8u)(ax2 & 0xFF);
AH = 0;
/* AAD effects the following flags: A,C,O,S,Z,P */
@ -165,30 +167,32 @@ BX_CPU_C::AAD(bxInstruction_c *i)
void
BX_CPU_C::DAA(bxInstruction_c *)
{
Bit8u al;
al = AL;
Bit8u tmpAL = AL;
int tmpCF = 0;
// DAA affects the following flags: S,Z,A,P,C
// ???
if (((al & 0x0F) > 0x09) || get_AF()) {
al = al + 0x06;
if (((AL & 0x0F) > 0x09) || get_AF())
{
tmpAL = AL + 0x06;
if (get_CF() || (tmpAL < AL)) tmpCF = 1;
set_AF(1);
}
}
else
set_AF(0);
if ((al > 0x9F) || get_CF()) {
al = al + 0x60;
set_CF(1);
}
if ((AL > 0x99) || get_CF())
{
tmpAL = AL + 0x60;
tmpCF = 1;
}
else
set_CF(0);
tmpCF = 0;
AL = al;
AL = tmpAL;
set_SF(al >> 7);
set_ZF(al==0);
set_PF_base(al);
set_CF(tmpCF);
set_SF(tmpAL >> 7);
set_ZF(tmpAL==0);
set_PF_base(tmpAL);
}