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Simplify is_supervisor semantics.

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This commit is contained in:
Thomas Harte 2022-05-13 07:53:40 -04:00
parent 2e796f31d4
commit 6c854e8ecc
2 changed files with 12 additions and 12 deletions
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19
InstructionSets/M68k/Implementation/ExecutorImplementation.hpp
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@ -43,7 +43,7 @@ void Executor<model, BusHandler>::reset_processor() {
template <Model model, typename BusHandler> template <Model model, typename BusHandler>
template <typename IntT> template <typename IntT>
IntT Executor<model, BusHandler>::read(uint32_t address, bool is_from_pc) { IntT Executor<model, BusHandler>::read(uint32_t address, bool is_from_pc) {
const auto code = FunctionCode((status_.is_supervisor << 2) | 1 << int(is_from_pc)); const auto code = FunctionCode((active_stack_pointer_ << 2) | 1 << int(is_from_pc));
if(model == Model::M68000 && sizeof(IntT) > 1 && address & 1) { if(model == Model::M68000 && sizeof(IntT) > 1 && address & 1) {
throw AccessException(code, address, Exception::AddressError | (int(is_from_pc) << 3) | (1 << 4)); throw AccessException(code, address, Exception::AddressError | (int(is_from_pc) << 3) | (1 << 4));
} }
@ -55,7 +55,7 @@ IntT Executor<model, BusHandler>::read(uint32_t address, bool is_from_pc) {
template <Model model, typename BusHandler> template <Model model, typename BusHandler>
template <typename IntT> template <typename IntT>
void Executor<model, BusHandler>::write(uint32_t address, IntT value) { void Executor<model, BusHandler>::write(uint32_t address, IntT value) {
const auto code = FunctionCode((status_.is_supervisor << 2) | 1); const auto code = FunctionCode((active_stack_pointer_ << 2) | 1);
if(model == Model::M68000 && sizeof(IntT) > 1 && address & 1) { if(model == Model::M68000 && sizeof(IntT) > 1 && address & 1) {
throw AccessException(code, address, Exception::AddressError); throw AccessException(code, address, Exception::AddressError);
} }
@ -245,7 +245,7 @@ void Executor<model, BusHandler>::run_for_instructions(int count) {
// Grab the status to store, then switch into supervisor mode. // Grab the status to store, then switch into supervisor mode.
const uint16_t status = status_.status(); const uint16_t status = status_.status();
status_.is_supervisor = 1; status_.is_supervisor = true;
status_.trace_flag = 0; status_.trace_flag = 0;
did_update_status(); did_update_status();
@ -292,7 +292,7 @@ void Executor<model, BusHandler>::run(int &count) {
instruction_opcode_ = read_pc<uint16_t>(); instruction_opcode_ = read_pc<uint16_t>();
const Preinstruction instruction = decoder_.decode(instruction_opcode_); const Preinstruction instruction = decoder_.decode(instruction_opcode_);
if(!status_.is_supervisor && instruction.requires_supervisor()) { if(instruction.requires_supervisor() && !status_.is_supervisor) {
raise_exception(Exception::PrivilegeViolation); raise_exception(Exception::PrivilegeViolation);
continue; continue;
} }
@ -383,7 +383,7 @@ typename Executor<model, BusHandler>::Registers Executor<model, BusHandler>::get
result.status = status_.status(); result.status = status_.status();
result.program_counter = program_counter_.l; result.program_counter = program_counter_.l;
stack_pointers_[status_.is_supervisor] = sp; stack_pointers_[active_stack_pointer_] = sp;
result.user_stack_pointer = stack_pointers_[0].l; result.user_stack_pointer = stack_pointers_[0].l;
result.supervisor_stack_pointer = stack_pointers_[1].l; result.supervisor_stack_pointer = stack_pointers_[1].l;
@ -399,11 +399,12 @@ void Executor<model, BusHandler>::set_state(const Registers &state) {
An(c).l = state.address[c]; An(c).l = state.address[c];
} }
status_.set_status(state.status); status_.set_status(state.status);
did_update_status();
program_counter_.l = state.program_counter; program_counter_.l = state.program_counter;
stack_pointers_[0].l = state.user_stack_pointer; stack_pointers_[0].l = state.user_stack_pointer;
stack_pointers_[1].l = state.supervisor_stack_pointer; stack_pointers_[1].l = state.supervisor_stack_pointer;
sp = stack_pointers_[status_.is_supervisor]; sp = stack_pointers_[active_stack_pointer_];
} }
// MARK: - Flow Control. // MARK: - Flow Control.
@ -416,7 +417,7 @@ void Executor<model, BusHandler>::raise_exception(int index) {
// Grab the status to store, then switch into supervisor mode // Grab the status to store, then switch into supervisor mode
// and disable tracing. // and disable tracing.
const uint16_t status = status_.status(); const uint16_t status = status_.status();
status_.is_supervisor = 1; status_.is_supervisor = true;
status_.trace_flag = 0; status_.trace_flag = 0;
did_update_status(); did_update_status();
@ -433,8 +434,8 @@ template <Model model, typename BusHandler>
void Executor<model, BusHandler>::did_update_status() { void Executor<model, BusHandler>::did_update_status() {
// Shuffle the stack pointers. // Shuffle the stack pointers.
stack_pointers_[active_stack_pointer_] = sp; stack_pointers_[active_stack_pointer_] = sp;
sp = stack_pointers_[status_.is_supervisor]; sp = stack_pointers_[int(status_.is_supervisor)];
active_stack_pointer_ = status_.is_supervisor; active_stack_pointer_ = int(status_.is_supervisor);
} }
template <Model model, typename BusHandler> template <Model model, typename BusHandler>

5
InstructionSets/M68k/Status.hpp
View File

@ -39,8 +39,7 @@ struct Status {
FlagT trace_flag = 0; // The trace flag is set if and only if this value is non-zero. FlagT trace_flag = 0; // The trace flag is set if and only if this value is non-zero.
/* b13 */ /* b13 */
int is_supervisor = 0; // 1 => processor is in supervisor mode; 0 => it isn't. bool is_supervisor = false; // true => processor is in supervisor mode; false => it isn't.
// All other values have undefined meaning.
/* b7–b9 */ /* b7–b9 */
int interrupt_level = 0; // The direct integer value of the current interrupt level. int interrupt_level = 0; // The direct integer value of the current interrupt level.
@ -89,7 +88,7 @@ struct Status {
interrupt_level = (status >> 8) & 7; interrupt_level = (status >> 8) & 7;
trace_flag = status & ConditionCode::Trace; trace_flag = status & ConditionCode::Trace;
is_supervisor = (status & ConditionCode::Supervisor) ? 1 : 0; is_supervisor = status & ConditionCode::Supervisor;
return is_supervisor; return is_supervisor;
} }