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Made some elementary attempt to hit something like the correct states within the VIC.

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This commit is contained in:
Thomas Harte 2016-06-05 17:06:10 -04:00
parent 9e9e50edb1
commit 444d3b69b6
2 changed files with 93 additions and 5 deletions
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88
Components/6560/6560.cpp
View File

@ -10,8 +10,30 @@
using namespace MOS;
/*
0 - 0000 Black
1 - 0001 White
2 - 0010 Red
3 - 0011 Cyan
4 - 0100 Purple
5 - 0101 Green
6 - 0110 Blue
7 - 0111 Yellow
8 - 1000 Orange
9 - 1001 Light orange
10 - 1010 Pink
11 - 1011 Light cyan
12 - 1100 Light purple
13 - 1101 Light green
14 - 1110 Light blue
15 - 1111 Light yellow
*/
MOS6560::MOS6560() :
_crt(new Outputs::CRT::CRT(65 * 4, 4, Outputs::CRT::DisplayType::NTSC60, 1))
_crt(new Outputs::CRT::CRT(65 * 4, 4, Outputs::CRT::DisplayType::NTSC60, 1)),
_horizontal_counter(0),
_vertical_counter(0)
{
_crt->set_rgb_sampling_function(
"vec3 rgb_sample(usampler2D sampler, vec2 coordinate, vec2 icoordinate)"
@ -49,22 +71,78 @@ void MOS6560::set_register(int address, uint8_t value)
break;
case 0xf:
// TODO: colours
_invertedCells = !!((value >> 3)&1);
_borderColour = value & 0x07;
_backgroundColour = value >> 4;
break;
// TODO: audio, primarily
default:
break;
}
// printf("%02x: %02x\n", address, value);
// printf("%04x %04x [%d by %d from %d, %d]\n", _character_cell_start_address, _video_matrix_start_address, _number_of_columns, _number_of_rows, _first_column_location, _first_row_location);
}
uint16_t MOS6560::get_address()
{
/*
Per http://tinyvga.com/6561 :
The basic video timing is very simple. For
every character the VIC-I is about to display, it first fetches the
character code and colour, then the character appearance (from the
character generator memory). The character codes are read on every
raster line, thus making every line a "bad line". When the raster
beam is outside of the text window, the videochip reads from $001c for
most time. (Some videochips read from $181c instead.) The address
occasionally varies, but it might also be due to a flaky bus. (By
reading from unconnected address space, such as $9100-$910f, you can
read the data fetched by the videochip on the previous clock cycle.)
*/
State this_state;
// random guesses; who knows?
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)
{
_horizontal_counter = 0;
_vertical_counter++;
_column_counter = -1;
if(_vertical_counter == 261)
{
_vertical_counter = 0;
_row_counter = -1;
}
if(_row_counter >= 0)
{
_row_counter++;
if(_row_counter == _number_of_rows*8) _row_counter = -1;
}
else if(_vertical_counter >= _first_row_location * 2) _row_counter = 0;
}
if(_column_counter >= 0)
{
_column_counter++;
if(_column_counter == _number_of_columns*2)
_column_counter = -1;
}
else if(_horizontal_counter == _first_column_location) _column_counter = 0;
return 0x1c;
}
void MOS6560::set_graphics_value(uint8_t value, uint8_t colour_value)
{
}

10
Components/6560/6560.hpp
View File

@ -30,6 +30,16 @@ class MOS6560 {
uint8_t _first_column_location, _first_row_location;
uint8_t _number_of_columns, _number_of_rows;
uint16_t _character_cell_start_address, _video_matrix_start_address;
uint8_t _backgroundColour, _borderColour;
bool _invertedCells;
int _horizontal_counter, _vertical_counter;
int _column_counter, _row_counter;
enum State {
Sync, ColourBurst, Border, Pixels
};
};
}