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Implements out-of-video-area pauses.

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This commit is contained in:
Thomas Harte 2021-06-27 16:11:22 -04:00
parent 903e343895
commit 895d98e266
1 changed files with 43 additions and 4 deletions
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47
Machines/Enterprise/Enterprise.cpp
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@ -226,9 +226,31 @@ template <bool has_disk_controller> class ConcreteMachine:
const uint16_t address = cycle.address ? *cycle.address : 0x0000;
// TODO: possibly apply an access penalty.
HalfCycles penalty;
if(is_video_[address >> 14]) {
// TODO.
} else {
switch(cycle.operation) {
default: break;
time_since_audio_update_ += cycle.length;
if(nick_ += cycle.length) {
case CPU::Z80::PartialMachineCycle::ReadStart:
case CPU::Z80::PartialMachineCycle::WriteStart:
if(wait_mode_ == WaitMode::OnAllAccesses) {
penalty = HalfCycles(2);
}
break;
case CPU::Z80::PartialMachineCycle::ReadOpcodeStart:
if(wait_mode_ != WaitMode::None) {
penalty = HalfCycles(2);
}
break;
}
}
const HalfCycles full_length = cycle.length + penalty;
time_since_audio_update_ += full_length;
if(nick_ += full_length) {
const auto nick = nick_.last_valid();
const bool nick_interrupt_line = nick->get_interrupt_line();
if(nick_interrupt_line && !previous_nick_interrupt_line_) {
@ -239,7 +261,7 @@ template <bool has_disk_controller> class ConcreteMachine:
// The WD/etc runs at a nominal 8Mhz.
if constexpr (has_disk_controller) {
exdos_.run_for(Cycles(cycle.length.as_integral()));
exdos_.run_for(Cycles(full_length.as_integral()));
}
switch(cycle.operation) {
@ -338,6 +360,11 @@ template <bool has_disk_controller> class ConcreteMachine:
break;
case 0xbf:
printf("TODO: Dave sysconfig %02x\n", *cycle.value);
switch((*cycle.value >> 2)&3) {
default: wait_mode_ = WaitMode::None; break;
case 0: wait_mode_ = WaitMode::OnAllAccesses; break;
case 1: wait_mode_ = WaitMode::OnM1; break;
}
break;
}
break;
@ -358,7 +385,7 @@ template <bool has_disk_controller> class ConcreteMachine:
break;
}
return HalfCycles(0);
return penalty;
}
void flush() {
@ -392,6 +419,7 @@ template <bool has_disk_controller> class ConcreteMachine:
#define Map(location, source) \
if(offset >= location && offset < location + source.size() / 0x4000) { \
page<slot>(&source[(offset - location) * 0x4000], nullptr); \
is_video_[slot] = false; \
return; \
}
@ -409,6 +437,7 @@ template <bool has_disk_controller> class ConcreteMachine:
if(offset >= min_ram_slot_) {
const auto ram_floor = 4194304 - ram_.size();
const size_t address = offset * 0x4000 - ram_floor;
is_video_[slot] = offset >= 0xfc; // TODO: this hard-codes a 64kb video assumption.
page<slot>(&ram_[address], &ram_[address]);
return;
}
@ -421,6 +450,16 @@ template <bool has_disk_controller> class ConcreteMachine:
write_pointers_[slot] = write ? write - (slot * 0x4000) : nullptr;
}
// MARK: - Memory Timing
// The wait mode affects all memory accesses _outside of the video area_.
enum class WaitMode {
None,
OnM1,
OnAllAccesses
} wait_mode_ = WaitMode::None;
bool is_video_[4]{};
// MARK: - ScanProducer
void set_scan_target(Outputs::Display::ScanTarget *scan_target) override {
nick_.last_valid()->set_scan_target(scan_target);