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- AAM can generate an exception (divide by 0)

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- AAM: modification of flags depends on AL, not AX
- AAM always clears CF and AF
- AAD can also modify AF, CF and OF
- DAA can also clear the CF
This commit is contained in:
Volker Ruppert 2002-07-06 11:02:35 +00:00
parent 70eb02913b
commit 27fedb5aba
1 changed files with 25 additions and 8 deletions
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33
bochs/cpu/bcd.cc
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@ -1,8 +1,8 @@
/////////////////////////////////////////////////////////////////////////
// $Id: bcd.cc,v 1.5 2001-10-03 13:10:37 bdenney Exp $
// $Id: bcd.cc,v 1.6 2002-07-06 11:02:35 vruppert Exp $
/////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2001 MandrakeSoft S.A.
// Copyright (C) 2002 MandrakeSoft S.A.
//
// MandrakeSoft S.A.
// 43, rue d'Aboukir
@ -121,27 +121,42 @@ BX_CPU_C::AAM(BxInstruction_t *i)
imm8 = i->Ib;
if (imm8 == 0) {
exception(BX_DE_EXCEPTION, 0, 0);
}
al = AL;
AH = al / imm8;
AL = al % imm8;
/* AAM always clears the flags A and C */
set_AF(0);
set_CF(0);
/* AAM affects the following flags: S,Z,P */
set_SF((AH & 0x80) > 0);
set_ZF(AX==0);
set_PF_base(AL); /* ??? */
set_SF((AL & 0x80) > 0);
set_ZF(AL == 0);
set_PF_base(AL);
}
void
BX_CPU_C::AAD(BxInstruction_t *i)
{
Bit8u imm8;
Bit8u al, imm8;
Bit16u ax1, ax2;
imm8 = i->Ib;
AL = AH * imm8 + AL;
ax1 = AH * imm8;
ax2 = ax1 + AL;
al = AL;
AL = (Bit8u)ax2;
AH = 0;
/* AAD effects the following flags: S,Z,P */
/* AAD effects the following flags: A,C,O,S,Z,P */
/* modification of flags A,C,O is undocumented */
set_AF((ax1 & 0x08) != (ax2 & 0x08));
set_CF(ax2 > 0xff);
set_OF((AL & 0x80) != (al & 0x80));
set_SF(AL >= 0x80);
set_ZF(AL == 0);
set_PF_base(AL);
@ -168,6 +183,8 @@ BX_CPU_C::DAA(BxInstruction_t *)
al = al + 0x60;
set_CF(1);
}
else
set_CF(0);
AL = al;