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mirror of https://github.com/TomHarte/CLK.git synced 2024-07-07 08:28:57 +00:00

Made some basic first attempt at parsing video attributes; ensured lowest byte of ROM is readable.

This commit is contained in:
Thomas Harte 2016-10-13 07:59:11 -04:00
parent ae48ad1bb4
commit 69920a4979
3 changed files with 53 additions and 10 deletions

View File

@ -26,7 +26,7 @@ void Machine::set_rom(std::vector<uint8_t> data)
unsigned int Machine::perform_bus_operation(CPU6502::BusOperation operation, uint16_t address, uint8_t *value)
{
if(address > 0xc000)
if(address >= 0xc000)
{
if(isReadOperation(operation)) *value = _rom[address&16383];
}

View File

@ -14,7 +14,8 @@ VideoOutput::VideoOutput(uint8_t *memory) :
_ram(memory),
_frame_counter(0), _counter(0),
_state(Sync), _cycles_in_state(0),
_is_graphics_mode(false)
_is_graphics_mode(false),
_character_set_base_address(0xb400)
{
_crt.reset(new Outputs::CRT::CRT(64*6, 6, Outputs::CRT::DisplayType::PAL50, 1));
@ -41,9 +42,16 @@ void VideoOutput::run_for_cycles(int number_of_cycles)
while(number_of_cycles--)
{
_counter = (_counter + 1)%(312 * 64); // TODO: NTSC
int h_counter =_counter & 63;
if(!h_counter)
{
_ink = 0xff;
_paper = 0x00;
_style = 0x00; // TODO: this means standard-size standard charset?
}
State new_state = Blank;
int h_counter =_counter & 63;
if(
(h_counter >= 48 && h_counter <= 53) ||
(_counter >= 256*64 && _counter <= 259*64)) new_state = Sync;
@ -64,20 +72,54 @@ void VideoOutput::run_for_cycles(int number_of_cycles)
_cycles_in_state++;
if(new_state == Pixels) {
uint8_t pixels;
uint8_t pixels, control_byte;
if(_is_graphics_mode)
{
// TODO
control_byte = pixels = _ram[0xa000 + (_counter >> 6) * 40 + h_counter];
}
else
{
int address = 0xbb80 + (_counter >> 9) * 40 + h_counter;
uint8_t character = _ram[address];
pixels = _ram[0xb400 + character * 8 + ((_counter >> 6) & 7)];
control_byte = _ram[address];
pixels = _ram[_character_set_base_address + control_byte * 8 + ((_counter >> 6) & 7)];
}
if((control_byte & 0x7f) >= 32)
{
uint8_t colours[2] = {
(control_byte & 0x80) ? _ink : _paper,
(control_byte & 0x80) ? _paper : _ink,
};
_pixel_target[0] = (colours[(pixels >> 4)&1] & 0x0f) | (colours[(pixels >> 5)&1] & 0xf0);
_pixel_target[1] = (colours[(pixels >> 2)&1] & 0x0f) | (colours[(pixels >> 3)&1] & 0xf0);
_pixel_target[2] = (colours[(pixels >> 0)&1] & 0x0f) | (colours[(pixels >> 1)&1] & 0xf0);
}
else
{
switch(control_byte & 0x7f)
{
case 0x00: _ink = 0x00; break;
case 0x01: _ink = 0x44; break;
case 0x02: _ink = 0x22; break;
case 0x03: _ink = 0x66; break;
case 0x04: _ink = 0x11; break;
case 0x05: _ink = 0x55; break;
case 0x06: _ink = 0x33; break;
case 0x07: _ink = 0x77; break;
case 0x10: _paper = 0x00; break;
case 0x11: _paper = 0x44; break;
case 0x12: _paper = 0x22; break;
case 0x13: _paper = 0x66; break;
case 0x14: _paper = 0x11; break;
case 0x15: _paper = 0x55; break;
case 0x16: _paper = 0x33; break;
case 0x17: _paper = 0x77; break;
default: break;
}
_pixel_target[0] = _pixel_target[1] = _pixel_target[2] = _paper;
}
_pixel_target[0] = ((pixels & 0x10) ? 0xf : 0x0) | ((pixels & 0x20) ? 0xf0 : 0x00);
_pixel_target[1] = ((pixels & 0x04) ? 0xf : 0x0) | ((pixels & 0x08) ? 0xf0 : 0x00);
_pixel_target[2] = ((pixels & 0x01) ? 0xf : 0x0) | ((pixels & 0x02) ? 0xf0 : 0x00);
_pixel_target += 3;
}
}

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@ -35,6 +35,7 @@ class VideoOutput {
// Registers
uint8_t _ink, _style, _paper;
int _character_set_base_address;
bool _is_graphics_mode;
};