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Use increment_video_counter_ to trigger fetch.

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This commit is contained in:
Thomas Harte 2024-12-31 08:06:04 -05:00
parent 60856b974b
commit 6197486d49
1 changed files with 15 additions and 21 deletions
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36
Machines/Commodore/Plus4/Video.hpp
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@ -287,13 +287,15 @@ public:
next_cursor_.advance();
}
if(increment_video_counter_) {
// TODO: I've not fully persuaded myself yet that these shouldn't be the other side of the advance,
// subject to another latch in the pipeline. I need to figure out whether pixel[char/attr] are
// artefacts of the FPGA version not being able to dump 8 pixels simultaneously or act as extra
// delay. They'll probably need to come back either way once I observe x_scroll_.
//
// Current thinking: these should probably go afterwards, with an equivalent of pixelshiftreg
// adding further delay?
const uint16_t address = video_matrix_base_ + video_counter_;
if(bad_line2_) {
shifter_.write<1>(pager_.read(address));
} else {
const auto data = pager_.read(address + 0x400);
shifter_.write<0>(data);
if(bad_line()) next_character_.write(data);
}
next_attribute_.write(shifter_.read<1>());
if(!bad_line()) next_character_.write(shifter_.read<0>());
next_cursor_.write(
@ -306,23 +308,13 @@ public:
);
shifter_.advance();
++video_counter_;
}
if(increment_character_position_ && character_fetch_) {
++character_position_;
}
if(dma_state_ == DMAState::TDMA) {
const uint16_t address = video_matrix_base_ + video_counter_;
if(bad_line2_) {
shifter_.write<1>(pager_.read(address));
} else {
const auto data = pager_.read(address + 0x400);
shifter_.write<0>(data);
if(bad_line()) next_character_.write(data);
}
}
if(state == OutputState::Pixels && pixels_) {
const auto pixel_address = next_character_.read();
const auto pixels = pager_.read(uint16_t(
@ -422,6 +414,7 @@ public:
schedule<8>(DelayedEvent::IncrementVerticalLine);
next_vertical_counter_ = video_line_ == eos() ? 0 : ((vertical_counter_ + 1) & 511);
horizontal_burst_ = true;
printf("\n");
break;
case HorizontalEvent::EndExternalFetchWindow:
@ -643,7 +636,7 @@ private:
}
template<int channel>
void write(uint8_t value) {
data_[channel][(cursor_ + 1) % 40] = value;
data_[channel][cursor_] = value;
}
void advance() {
++cursor_;
@ -665,6 +658,7 @@ private:
return uint8_t(data_);
}
void write(uint8_t value) {
static_assert(cycles_delay < sizeof(data_));
data_ |= uint32_t(value) << (cycles_delay * 8);
}
void advance() {
@ -674,8 +668,8 @@ private:
private:
uint32_t data_;
};
ShiftRegister<2> next_attribute_;
ShiftRegister<2> next_character_;
ShiftRegister<3> next_attribute_;
ShiftRegister<3> next_character_;
ShiftRegister<3> next_cursor_;
// List of counter-triggered events.