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Factor out the common stuff of exception state.

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This commit is contained in:
Thomas Harte 2022-06-01 08:20:33 -04:00
parent 73815ba1dd
commit 75e85b80aa
2 changed files with 26 additions and 20 deletions
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17
InstructionSets/M68k/Status.hpp
View File

@ -95,6 +95,23 @@ struct Status {
return is_supervisor;
}
/// Adjusts the status for exception processing — sets supervisor mode, disables trace,
/// and if @c new_interrupt_level is greater than or equal to 0 sets that as the new
/// interrupt level.
///
/// @returns The status prior to those changes.
uint16_t begin_exception(int new_interrupt_level = -1) {
const uint16_t initial_status = status();
if(new_interrupt_level >= 0) {
interrupt_level = new_interrupt_level;
}
is_supervisor = true;
trace_flag = 0;
return initial_status;
}
/// Evaluates @c condition.
bool evaluate_condition(Condition condition) {
switch(condition) {

21
Processors/68000Mk2/Implementation/68000Mk2Implementation.hpp
View File

@ -355,9 +355,7 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
IdleBus(7); // (n-)*5 nn
// Establish general reset state.
status_.is_supervisor = true;
status_.interrupt_level = 7;
status_.trace_flag = 0;
status_.begin_exception(7);
should_trace_ = 0;
did_update_status();
@ -383,11 +381,8 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
// Perform a 'standard' exception, i.e. a Group 1 or 2.
BeginState(StandardException):
captured_status_.w = status_.status();
// Switch to supervisor mode, disable interrupts.
status_.is_supervisor = true;
status_.trace_flag = 0;
captured_status_.w = status_.begin_exception();
should_trace_ = 0;
did_update_status();
@ -451,13 +446,10 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
// 4) function code;
// 5) access address?
captured_status_.w = status_.status();
IdleBus(2);
// Switch to supervisor mode, disable interrupts.
status_.is_supervisor = true;
status_.trace_flag = 0;
status_.interrupt_level = 7;
captured_status_.w = status_.begin_exception(7);
should_trace_ = 0;
did_update_status();
@ -515,10 +507,7 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
IdleBus(3); // n nn
// Capture status and switch to supervisor mode.
captured_status_.w = status_.status();
status_.is_supervisor = true;
status_.trace_flag = 0;
status_.interrupt_level = captured_interrupt_level_;
captured_status_.w = status_.begin_exception(captured_interrupt_level_);
should_trace_ = 0;
did_update_status();
@ -608,7 +597,7 @@ void Processor<BusHandler, dtack_is_implicit, permit_overrun, signal_will_perfor
/// If operation x requires supervisor privileges, checks whether the user is currently in supervisor mode;
/// if not then raises a privilege violation exception.
#define CheckSupervisor(x) \
if constexpr (InstructionSet::M68k::requires_supervisor<InstructionSet::M68k::Model::M68000, InstructionSet::M68k::Operation::x>()) { \
if constexpr (InstructionSet::M68k::requires_supervisor<InstructionSet::M68k::Model::M68000>(InstructionSet::M68k::Operation::x)) { \
if(!status_.is_supervisor) { \
RaiseException(InstructionSet::M68k::Exception::PrivilegeViolation); \
} \