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Fix to imul not being correct with sign extension

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Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@548
This commit is contained in:
Sjoerd van der Berg 2002-11-30 11:46:08 +00:00
parent f2ee392b0e
commit 43801a39c2
1 changed files with 4 additions and 4 deletions
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8
src/cpu/core_16/prefix_66.h
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@ -436,7 +436,7 @@ switch(Fetchb()) {
case 0x20: /* MUL EAX,Ed */
{
flags.type=t_MUL;
if (rm >= 0xc0 ) {GetEArd;temp.u=(Bit64s)reg_eax * (Bit64u)(*eard);}
if (rm >= 0xc0 ) {GetEArd;temp.u=(Bit64u)reg_eax * (Bit64u)(*eard);}
else {GetEAa;temp.u=(Bit64u)reg_eax * (Bit64u)LoadMd(eaa);}
reg_eax=(Bit32u)(temp.u & 0xffffffff);reg_edx=(Bit32u)(temp.u >> 32);
flags.cf=flags.of=(reg_edx !=0);
@ -445,9 +445,9 @@ switch(Fetchb()) {
case 0x28: /* IMUL EAX,Ed */
{
flags.type=t_MUL;
if (rm >= 0xc0 ) {GetEArd;temp.s=(Bit64s)reg_eax * (Bit64s)(*eards);}
else {GetEAa;temp.s=(Bit64s)reg_eax * (Bit64s)LoadMds(eaa);}
reg_eax=Bit32u(temp.u & 0xffffffff);reg_edx=(Bit32u)(temp.u >> 32);
if (rm >= 0xc0 ) {GetEArd;temp.s=((Bit64s)((Bit32s)reg_eax) * (Bit64s)(*eards));}
else {GetEAa;temp.s=((Bit64s)((Bit32s)reg_eax) * (Bit64s)(LoadMds(eaa)));}
reg_eax=Bit32u(temp.s & 0xffffffff);reg_edx=(Bit32u)(temp.s >> 32);
if ( (reg_edx==0xffffffff) && (reg_eax & 0x80000000) ) {
flags.cf=flags.of=false;
} else if ( (reg_edx==0x00000000) && (reg_eax<0x80000000) ) {