void
POPF_Fw(void)
{
UINT16 flags, mask;
CPU_WORKCLOCK(3);
if (!CPU_STAT_PM) {
/* Real Mode */
POP0_16(flags);
mask = I_FLAG|IOPL_FLAG;
} else if (!CPU_STAT_VM86) {
/* Protected Mode */
POP0_16(flags);
if (CPU_STAT_CPL == 0) {
mask = I_FLAG|IOPL_FLAG;
} else if (CPU_STAT_CPL <= CPU_STAT_IOPL) {
mask = I_FLAG;
} else {
mask = 0;
}
} else if (CPU_STAT_IOPL == CPU_IOPL3) {
/* Virtual-8086 Mode, IOPL == 3 */
POP0_16(flags);
mask = I_FLAG;
} else {
EXCEPTION(GP_EXCEPTION, 0);
flags = 0;
mask = 0;
/* compiler happy */
}
set_eflags(flags, mask);
IRQCHECKTERM();
}
void
IRET(void)
{
descriptor_t sd;
UINT32 new_ip;
UINT32 new_flags;
UINT32 new_cs;
UINT32 mask;
UINT16 sreg;
CPU_WORKCLOCK(22);
if (!CPU_STAT_PM) {
/* Real mode */
CPU_SET_PREV_ESP();
mask = I_FLAG|IOPL_FLAG;
if (!CPU_INST_OP32) {
POP0_16(new_ip);
POP0_16(new_cs);
POP0_16(new_flags);
} else {
POP0_32(new_ip);
POP0_32(new_cs);
POP0_32(new_flags);
mask |= RF_FLAG;
}
/* check new instrunction pointer with new code segment */
load_segreg(CPU_CS_INDEX, new_cs, &sreg, &sd, GP_EXCEPTION);
if (new_ip > sd.u.seg.limit) {
EXCEPTION(GP_EXCEPTION, 0);
}
LOAD_SEGREG(CPU_CS_INDEX, (UINT16)new_cs);
CPU_EIP = new_ip;
set_eflags(new_flags, mask);
CPU_CLEAR_PREV_ESP();
} else {
/* Protected mode */
IRET_pm();
}
IRQCHECKTERM();
}
void
STI(void)
{
CPU_WORKCLOCK(2);
if (CPU_STAT_PM) {
if (!CPU_STAT_VM86) {
if (CPU_STAT_CPL > CPU_STAT_IOPL) {
EXCEPTION(GP_EXCEPTION, 0);
}
} else {
if (CPU_STAT_IOPL < 3) {
EXCEPTION(GP_EXCEPTION, 0);
}
}
}
CPU_FLAG |= I_FLAG;
CPU_TRAP = (CPU_FLAG & (I_FLAG|T_FLAG)) == (I_FLAG|T_FLAG);
exec_1step();
IRQCHECKTERM();
}