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Add buffer for pixels, output _something_.

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This commit is contained in:
Thomas Harte 2024-12-13 13:31:15 -05:00
parent 363ad7342a
commit ff92bdb324
2 changed files with 33 additions and 5 deletions
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9
Machines/Commodore/Plus4/Plus4.cpp
View File

@ -115,7 +115,7 @@ public:
// NTSC: 7159090?
// i.e. colour subcarriers multiplied by two?
set_clock_rate(7159090); // TODO.
set_clock_rate(8867240); // TODO.
const auto kernel = ROM::Name::Plus4KernelPALv5;
const auto basic = ROM::Name::Plus4BASIC;
@ -141,8 +141,9 @@ public:
const uint16_t address,
uint8_t *const value
) {
// TODO: calculate length of this bus operation.
const auto length = Cycles(5);
// Determine from the TED video subsystem the length of this clock cycle as perceived by the 6502,
// relative to the master clock.
const auto length = video_.cycle_length(operation == CPU::MOS6502::BusOperation::Ready);
// Update other subsystems.
// TODO: timers decrement at a 894 KHz rate for NTSC television systems, 884 KHZ for PAL systems.
@ -179,6 +180,7 @@ public:
case 0xff08:
// TODO: keyboard.
// For now: all keys unpressed.
*value = 0xff;
break;
@ -255,6 +257,7 @@ private:
}
void page_rom() {
// TODO: allow other ROM selection. And no ROM?
map_.page<PagerSide::Read, 0x8000, 16384>(basic_.data());
map_.page<PagerSide::Read, 0xc000, 16384>(kernel_.data());
}

29
Machines/Commodore/Plus4/Video.hpp
View File

@ -126,6 +126,18 @@ public:
// printf("bitmap:%d c256:%d ntsc:%d 40col:%d; base:%04x\n", bitmap_mode_, characters_256_, is_ntsc_, columns_40_, screen_memory_address_);
}
Cycles cycle_length([[maybe_unused]] bool is_ready) const {
// TODO: the complete test is more than this.
// TODO: if this is a RDY cycle, can reply with time until end-of-RDY.
const bool is_long_cycle = refresh_;
if(is_ntsc_) {
return is_long_cycle ? Cycles(8) : Cycles(4);
} else {
return is_long_cycle ? Cycles(10) : Cycles(5);
}
}
// Outer clock is [NTSC or PAL] colour subcarrier * 2.
//
// 65 cycles = 64µs?
@ -212,13 +224,25 @@ public:
case OutputState::Sync: crt_.output_sync(time_in_state_); break;
case OutputState::Burst: crt_.output_default_colour_burst(time_in_state_); break;
case OutputState::Border: crt_.output_level<uint16_t>(time_in_state_, background_[4]); break;
case OutputState::Pixels: crt_.output_level<uint16_t>(time_in_state_, background_[0]); break;
case OutputState::Pixels: crt_.output_data(time_in_state_, time_in_state_); break;
}
time_in_state_ = 0;
output_state_ = state;
if(output_state_ == OutputState::Pixels) {
pixels_ = reinterpret_cast<uint16_t *>(crt_.begin_data(384, 2));
}
}
output_state_ = state;
time_in_state_ += period;
// Output pixels. TODO: properly.
if(pixels_) {
for(int c = 0; c < period; c++) {
pixels_[c] = ((c + horizontal_counter_) & 1) ? 0x0000 : 0xffff;
}
pixels_ += period;
}
//
// Advance for current period.
//
@ -346,6 +370,7 @@ private:
Pixels,
} output_state_ = OutputState::Blank;
int time_in_state_ = 0;
uint16_t *pixels_ = nullptr;
std::array<uint16_t, 5> background_{};
std::array<uint8_t, 5> raw_background_{};