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Small further adjustments; seems likely to be correct now.

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This commit is contained in:
Thomas Harte 2019-03-16 23:01:56 -04:00
parent cf6fa98433
commit a8f1d98d40
1 changed files with 33 additions and 24 deletions
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57
Processors/68000/Implementation/68000Implementation.hpp
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@ -31,14 +31,38 @@ template <class T, bool dtack_is_implicit> void Processor<T, dtack_is_implicit>:
/* /*
PERFORM THE BUS STEP'S ACTION. PERFORM THE BUS STEP'S ACTION.
*/ */
// Consider advancing a micro-operation. if(!active_step_->is_terminal()) {
if(active_step_->is_terminal()) { switch(active_step_->action) {
// If there are any more micro-operations available, just move onwards. default:
if(active_micro_op_) { std::cerr << "Unimplemented 68000 bus step action: " << int(active_step_->action) << std::endl;
++active_micro_op_; return;
break;
case BusStep::Action::None: break;
case BusStep::Action::IncrementEffectiveAddress: effective_address_ += 2; break;
case BusStep::Action::IncrementProgramCounter: program_counter_.full += 2; break;
case BusStep::Action::AdvancePrefetch:
prefetch_queue_[0] = prefetch_queue_[1];
break;
} }
if(!active_micro_op_ || active_micro_op_->is_terminal()) { // Move to the next bus step.
++ active_step_;
// Skip the micro-op renavigation below.
continue;
}
/*
FIND THE NEXT MICRO-OP.
*/
while(true) {
// If there are any more micro-operations available, just move onwards.
if(active_micro_op_ && !active_micro_op_->is_terminal()) {
++active_micro_op_;
} else {
// Either the micro-operations for this instruction have been exhausted, or // Either the micro-operations for this instruction have been exhausted, or
// no instruction was ongoing. Either way, do a standard instruction operation. // no instruction was ongoing. Either way, do a standard instruction operation.
@ -54,8 +78,6 @@ template <class T, bool dtack_is_implicit> void Processor<T, dtack_is_implicit>:
active_micro_op_ = active_program_->micro_operations; active_micro_op_ = active_program_->micro_operations;
} }
// There is now a micro operation; cue up the first step and perform the predecessor action.
active_step_ = active_micro_op_->bus_program;
switch(active_micro_op_->action) { switch(active_micro_op_->action) {
case MicroOp::Action::None: break; case MicroOp::Action::None: break;
@ -139,25 +161,12 @@ template <class T, bool dtack_is_implicit> void Processor<T, dtack_is_implicit>:
active_program_->destination->full -= 4; active_program_->destination->full -= 4;
break; break;
} }
} else {
switch(active_step_->action) {
default:
std::cerr << "Unimplemented 68000 bus step action: " << int(active_step_->action) << std::endl;
return;
break;
case BusStep::Action::None: break; // If we've got to a micro-op that includes bus steps, break out of this loop.
if(!active_micro_op_->is_terminal()) {
case BusStep::Action::IncrementEffectiveAddress: effective_address_ += 2; break; active_step_ = active_micro_op_->bus_program;
case BusStep::Action::IncrementProgramCounter: program_counter_.full += 2; break;
case BusStep::Action::AdvancePrefetch:
prefetch_queue_[0] = prefetch_queue_[1];
break; break;
} }
// Move to the next bus step.
++ active_step_;
} }
} }
} }