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Implemented 16-bit task switching. Patch from Greatpsycho.

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This commit is contained in:
SarahW 2017-06-19 19:55:59 +01:00
commit 4446a6cdaf
1 changed files with 179 additions and 7 deletions
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186
src/x86seg.c
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@ -799,6 +799,7 @@ void loadcsjmp(uint16_t seg, uint32_t oxpc)
break;
case 0x100: /*286 Task gate*/
case 0x900: /*386 Task gate*/
// pclog("Task gate\n");
cpu_state.pc=oxpc;
@ -2102,7 +2103,7 @@ void pmodeiret(int is32)
segdat[1]=readmemw(0,addr+2);
segdat[2]=readmemw(0,addr+4);
segdat[3]=readmemw(0,addr+6);
taskswitch286(seg,segdat,0);
taskswitch286(seg,segdat,segdat[2] & 0x800);
cpl_override=0;
return;
}
@ -2418,16 +2419,19 @@ void taskswitch286(uint16_t seg, uint16_t *segdat, int is32)
uint16_t segdat2[4];
//output=3;
base=segdat[1]|((segdat[2]&0xFF)<<16)|((segdat[3]>>8)<<24);
limit=segdat[0]|((segdat[3]&0xF)<<16);
base=segdat[1]|((segdat[2]&0xFF)<<16);
limit=segdat[0];
// pclog("286 Task switch! %04X:%04X\n",CS,pc);
/// pclog("TSS %04X base %08X limit %04X old TSS %04X %08X %i\n",seg,base,limit,tr.seg,tr.base,ins);
// / pclog("%04X %04X %04X %04X\n",segdat[0],segdat[1],segdat[2],segdat[3]);
if (is386)
if (is32)
{
// if (output) pclog("32-bit TSS\n");
base |= (segdat[3]>>8)<<24;
limit |= (segdat[3]&0xF)<<16;
new_cr3=readmeml(base,0x1C);
new_pc=readmeml(base,0x20);
new_flags=readmeml(base,0x24);
@ -2629,8 +2633,176 @@ void taskswitch286(uint16_t seg, uint16_t *segdat, int is32)
}
else
{
pclog("16-bit TSS\n");
resetx86();
// pclog("16-bit TSS\n");
// resetx86();
new_pc=readmemw(base,0x0E);
new_flags=readmemw(base,0x10);
new_eax=readmemw(base,0x12);
new_ecx=readmemw(base,0x14);
new_edx=readmemw(base,0x16);
new_ebx=readmemw(base,0x18);
new_esp=readmemw(base,0x1A);
new_ebp=readmemw(base,0x1C);
new_esi=readmemw(base,0x1E);
new_edi=readmemw(base,0x20);
new_es=readmemw(base,0x22);
// if (output) pclog("Read CS from %08X\n",base+0x4C);
new_cs=readmemw(base,0x24);
new_ss=readmemw(base,0x26);
new_ds=readmemw(base,0x28);
new_ldt=readmemw(base,0x2A);
if (cpu_state.abrt) return;
if (optype==JMP || optype==OPTYPE_INT)
{
if (tr.seg&4) tempw=readmemw(ldt.base,(tr.seg&~7)+4);
else tempw=readmemw(gdt.base,(tr.seg&~7)+4);
if (cpu_state.abrt) return;
tempw&=~0x200;
if (tr.seg&4) writememw(ldt.base,(tr.seg&~7)+4,tempw);
else writememw(gdt.base,(tr.seg&~7)+4,tempw);
}
if (optype==IRET) flags&=~NT_FLAG;
// if (output) pclog("Write PC %08X %08X\n",tr.base,pc);
cpu_386_flags_rebuild();
writememw(tr.base,0x0E,cpu_state.pc);
writememw(tr.base,0x10,flags);
writememw(tr.base,0x12,AX);
writememw(tr.base,0x14,CX);
writememw(tr.base,0x16,DX);
writememw(tr.base,0x18,BX);
writememw(tr.base,0x1A,SP);
writememw(tr.base,0x1C,BP);
writememw(tr.base,0x1E,SI);
writememw(tr.base,0x20,DI);
writememw(tr.base,0x22,ES);
// if (output) pclog("Write CS %04X to %08X\n",CS,tr.base+0x4C);
writememw(tr.base,0x24,CS);
writememw(tr.base,0x26,SS);
writememw(tr.base,0x28,DS);
writememw(tr.base,0x2A,ldt.seg);
if (optype==OPTYPE_INT)
{
writememw(base,0,tr.seg);
new_flags|=NT_FLAG;
}
if (cpu_state.abrt) return;
if (optype==JMP || optype==OPTYPE_INT)
{
if (tr.seg&4) tempw=readmemw(ldt.base,(seg&~7)+4);
else tempw=readmemw(gdt.base,(seg&~7)+4);
if (cpu_state.abrt) return;
tempw|=0x200;
if (tr.seg&4) writememw(ldt.base,(seg&~7)+4,tempw);
else writememw(gdt.base,(seg&~7)+4,tempw);
}
cpu_state.pc=new_pc;
// if (output) pclog("New pc %08X\n",new_pc);
flags=new_flags;
cpu_386_flags_extract();
// if (output) pclog("Load LDT %04X\n",new_ldt);
ldt.seg=new_ldt;
templ=(ldt.seg&~7)+gdt.base;
// if (output) pclog("Load from %08X %08X\n",templ,gdt.base);
ldt.limit=readmemw(0,templ);
ldt.base=(readmemw(0,templ+2))|(readmemb(0,templ+4)<<16);
// if (output) pclog("Limit %04X Base %08X\n",ldt.limit,ldt.base);
if (!(new_cs&~3))
{
pclog("TS loading null CS\n");
x86gpf(NULL,0);
return;
}
addr=new_cs&~7;
if (new_cs&4)
{
if (addr>=ldt.limit)
{
pclog("Bigger than LDT limit %04X %04X %04X TS\n",new_cs,ldt.limit,addr);
x86gpf(NULL,0);
return;
}
addr+=ldt.base;
}
else
{
if (addr>=gdt.limit)
{
pclog("Bigger than GDT limit %04X %04X TS\n",new_cs,gdt.limit);
x86gpf(NULL,0);
return;
}
addr+=gdt.base;
}
segdat2[0]=readmemw(0,addr);
segdat2[1]=readmemw(0,addr+2);
segdat2[2]=readmemw(0,addr+4);
segdat2[3]=readmemw(0,addr+6);
if (!(segdat2[2]&0x8000))
{
pclog("TS loading CS not present\n");
x86np("TS loading CS not present\n", new_cs & 0xfffc);
return;
}
switch (segdat2[2]&0x1F00)
{
case 0x1800: case 0x1900: case 0x1A00: case 0x1B00: /*Non-conforming*/
if ((new_cs&3) != DPL2)
{
pclog("TS load CS non-conforming RPL != DPL");
x86gpf(NULL,new_cs&~3);
return;
}
break;
case 0x1C00: case 0x1D00: case 0x1E00: case 0x1F00: /*Conforming*/
if ((new_cs&3) < DPL2)
{
pclog("TS load CS non-conforming RPL < DPL");
x86gpf(NULL,new_cs&~3);
return;
}
break;
default:
pclog("TS load CS not code segment\n");
x86gpf(NULL,new_cs&~3);
return;
}
// if (output) pclog("new_cs %04X\n",new_cs);
CS=new_cs;
do_seg_load(&_cs, segdat2);
if (CPL==3 && oldcpl!=3) flushmmucache_cr3();
set_use32(0);
AX=new_eax;
CX=new_ecx;
DX=new_edx;
BX=new_ebx;
SP=new_esp;
BP=new_ebp;
SI=new_esi;
DI=new_edi;
if (output) pclog("Load ES %04X\n",new_es);
loadseg(new_es,&_es);
if (output) pclog("Load SS %04X\n",new_ss);
loadseg(new_ss,&_ss);
if (output) pclog("Load DS %04X\n",new_ds);
loadseg(new_ds,&_ds);
if (output) pclog("Resuming at %04X:%08X\n",CS,cpu_state.pc);
//exit(-1);
}