static void i80286_data_descriptor(i80286_state *cpustate,int reg, UINT16 selector)
{
if (PM) {
UINT16 help;
/* selector format
15..3 number/address in descriptor table
2: 0 global, 1 local descriptor table
1,0: requested privileg level
must be higher or same as current privileg level in code selector */
if (selector&4) { /* local descriptor table */
if (selector>cpustate->ldtr.limit) i80286_trap2(cpustate,GENERAL_PROTECTION_FAULT);
cpustate->sregs[reg]=selector;
cpustate->limit[reg]=ReadWord(cpustate->ldtr.base+(selector&~7));
cpustate->base[reg]=ReadWord(cpustate->ldtr.base+(selector&~7)+2)
|(ReadWord(cpustate->ldtr.base+(selector&~7)+4)<<16);
cpustate->rights[reg]=cpustate->base[reg]>>24;
cpustate->base[reg]&=0xffffff;
} else { /* global descriptor table */
if (!(selector&~7)||(selector>cpustate->gdtr.limit)) i80286_trap2(cpustate,GENERAL_PROTECTION_FAULT);
cpustate->sregs[reg]=selector;
cpustate->limit[reg]=ReadWord(cpustate->gdtr.base+(selector&~7));
cpustate->base[reg]=ReadWord(cpustate->gdtr.base+(selector&~7)+2);
help=ReadWord(cpustate->gdtr.base+(selector&~7)+4);
cpustate->rights[reg]=help>>8;
cpustate->base[reg]|=(help&0xff)<<16;
}
} else {
static void i80286_trap2(i80286_state *cpustate,UINT32 error)
{
int error_code = error & 0xffff;
UINT16 number = error >> 16;
if(error_code == 0xffff) error_code = -1;
cpustate->pc = cpustate->prevpc;
try {
switch(number) {
case DIVIDE_BY_ZERO:
case INVALID_TSS:
case SEG_NOT_PRESENT:
case STACK_FAULT:
case GENERAL_PROTECTION_FAULT:
cpustate->trap_level++;
if(cpustate->trap_level == 2) throw TRAP(DOUBLE_FAULT,0);
if(cpustate->trap_level == 3) break;
i80286_interrupt_descriptor(cpustate,number,1,error_code);
break;
case DOUBLE_FAULT:
i80286_interrupt_descriptor(cpustate,number,1,0);
break;
default:
i80286_interrupt_descriptor(cpustate,number,1,-1);
}
} catch(UINT32 e) { i80286_trap2(cpustate, e); }
if(cpustate->trap_level == 3)
// this is supposed to triggered by support hardware
// create a shutdown output line that causes a reset
// NMI can wake processor without reset
device_set_input_line(cpustate->device, INPUT_LINE_RESET, PULSE_LINE);
cpustate->trap_level = 0;
}
