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Advanced to having some characters displayed, even though they're obviously very much incorrect and the display is still rolling.

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This commit is contained in:
Thomas Harte 2016-06-06 07:35:35 -04:00
parent 79e05a2413
commit 64539a2b24
3 changed files with 51 additions and 18 deletions
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64
Components/6560/6560.cpp
View File

@ -97,14 +97,6 @@ void MOS6560::output_border(unsigned int number_of_cycles)
uint16_t MOS6560::get_address()
{
// determine output state; colour burst and sync timing are currently a guess
if(_horizontal_counter > 61) _this_state = State::ColourBurst;
else if(_horizontal_counter > 57) _this_state = State::Sync;
else
{
_this_state = (_column_counter >= 0 && _row_counter >= 0) ? State::Pixels : State::Border;
}
_horizontal_counter++;
if(_horizontal_counter == 65)
{
@ -123,16 +115,38 @@ uint16_t MOS6560::get_address()
_row_counter++;
if(_row_counter == _number_of_rows*8) _row_counter = -1;
}
else if(_vertical_counter >= _first_row_location * 2) _row_counter = 0;
else if(_vertical_counter >= _first_row_location * 2)
{
_video_matrix_line_address_counter = _video_matrix_start_address;
_row_counter = 0;
}
}
if(_column_counter >= 0)
{
_column_counter++;
if(_column_counter == _number_of_columns*2)
{
_column_counter = -1;
if((_row_counter&7) == 7)
{
_video_matrix_line_address_counter = _video_matrix_address_counter;
}
}
}
else if(_horizontal_counter == _first_column_location)
{
_column_counter = 0;
_video_matrix_address_counter = _video_matrix_line_address_counter;
}
// determine output state; colour burst and sync timing are currently a guess
if(_horizontal_counter > 61) _this_state = State::ColourBurst;
else if(_horizontal_counter > 57) _this_state = State::Sync;
else
{
_this_state = (_column_counter >= 0 && _row_counter >= 0) ? State::Pixels : State::Border;
}
else if(_horizontal_counter == _first_column_location) _column_counter = 0;
// update the CRT
if(_this_state != _output_state)
@ -172,11 +186,16 @@ uint16_t MOS6560::get_address()
reading from unconnected address space, such as $9100-$910f, you can
read the data fetched by the videochip on the previous clock cycle.)
*/
// TODO: increment this address
if(_column_counter&1)
return _character_cell_start_address + _character_code*8;
{
return _character_cell_start_address + (_character_code*8) + (_row_counter&7);
}
else
return _video_matrix_start_address;
{
uint16_t result = _video_matrix_address_counter;
_video_matrix_address_counter++;
return result;
}
}
return 0x1c;
@ -188,15 +207,28 @@ void MOS6560::set_graphics_value(uint8_t value, uint8_t colour_value)
{
if(_column_counter&1)
{
// TODO: output proper pixels here
_character_value = value;
if(pixel_pointer)
{
*pixel_pointer = (uint8_t)rand();
pixel_pointer++;
pixel_pointer[0] = ((value >> 7)&1) * 15;
pixel_pointer[1] = ((value >> 6)&1) * 15;
pixel_pointer[2] = ((value >> 5)&1) * 15;
pixel_pointer[3] = ((value >> 4)&1) * 15;
pixel_pointer += 4;
}
}
else
{
if(pixel_pointer)
{
pixel_pointer[0] = ((value >> 3)&1) * 15;
pixel_pointer[1] = ((value >> 2)&1) * 15;
pixel_pointer[2] = ((value >> 1)&1) * 15;
pixel_pointer[3] = ((value >> 0)&1) * 15;
pixel_pointer += 4;
}
_character_code = value;
_character_colour = colour_value;
}

3
Components/6560/6560.hpp
View File

@ -36,13 +36,14 @@ class MOS6560 {
int _horizontal_counter, _vertical_counter;
int _column_counter, _row_counter;
uint16_t _video_matrix_address_counter, _video_matrix_line_address_counter;
enum State {
Sync, ColourBurst, Border, Pixels
} _this_state, _output_state;
unsigned int _cycles_in_state;
uint8_t _character_code, _character_colour;
uint8_t _character_code, _character_colour, _character_value;
uint8_t *pixel_pointer;

2
Machines/Vic-20/Vic20.hpp
View File

@ -50,7 +50,7 @@ class Machine: public CPU6502::Processor<Machine>, public CRTMachine::Machine {
inline uint8_t *ram_pointer(uint16_t address) {
if(address < sizeof(_userBASICMemory)) return &_userBASICMemory[address];
if(address >= 0x1000 && address < 0x1200) return &_screenMemory[address&0x0fff];
if(address >= 0x1000 && address < 0x2000) return &_screenMemory[address&0x0fff];
if(address >= 0x9400 && address < 0x9600) return &_colorMemory[0x01ff];
return nullptr;
}