diff --git a/Components/6560/6560.cpp b/Components/6560/6560.cpp index c15968752..373cfc684 100644 --- a/Components/6560/6560.cpp +++ b/Components/6560/6560.cpp @@ -60,6 +60,7 @@ void MOS6560::set_output_mode(OutputMode output_mode) chrominances = pal_chrominances; display_type = Outputs::CRT::PAL50; _timing.cycles_per_line = 71; + _timing.line_counter_increment_offset = 0; _timing.lines_per_progressive_field = 312; _timing.supports_interlacing = false; break; @@ -68,6 +69,7 @@ void MOS6560::set_output_mode(OutputMode output_mode) chrominances = ntsc_chrominances; display_type = Outputs::CRT::NTSC60; _timing.cycles_per_line = 65; + _timing.line_counter_increment_offset = 65 - 36; // TODO: 36 is from memory; need to look up. _timing.lines_per_progressive_field = 261; _timing.supports_interlacing = true; break; @@ -147,11 +149,12 @@ void MOS6560::set_register(int address, uint8_t value) uint8_t MOS6560::get_register(int address) { address &= 0xf; + int current_line = (_full_frame_counter + _timing.line_counter_increment_offset) / _timing.cycles_per_line; switch(address) { default: return _registers.direct_values[address]; - case 0x03: return (uint8_t)(_vertical_counter << 7) | (_registers.direct_values[3] & 0x7f); - case 0x04: return (_vertical_counter >> 1) & 0xff; + case 0x03: return (uint8_t)(current_line << 7) | (_registers.direct_values[3] & 0x7f); + case 0x04: return (current_line >> 1) & 0xff; } } @@ -172,6 +175,7 @@ uint16_t MOS6560::get_address() // keep track of internal time relative to this scanline _horizontal_counter++; + _full_frame_counter++; if(_horizontal_counter == _timing.cycles_per_line) { if(_horizontal_drawing_latch) @@ -197,6 +201,7 @@ uint16_t MOS6560::get_address() if(_vertical_counter == (_registers.interlaced ? (_is_odd_frame ? 262 : 263) : _timing.lines_per_progressive_field)) { _vertical_counter = 0; + _full_frame_counter = 0; _is_odd_frame ^= true; _current_row = 0; diff --git a/Components/6560/6560.hpp b/Components/6560/6560.hpp index 562e1b754..1f06d8ca9 100644 --- a/Components/6560/6560.hpp +++ b/Components/6560/6560.hpp @@ -104,7 +104,7 @@ class MOS6560 { unsigned int _cycles_in_state; // counters that cover an entire field - int _horizontal_counter, _vertical_counter; + int _horizontal_counter, _vertical_counter, _full_frame_counter; // latches dictating start and length of drawing bool _vertical_drawing_latch, _horizontal_drawing_latch; @@ -129,6 +129,7 @@ class MOS6560 { struct { int cycles_per_line; + int line_counter_increment_offset; int lines_per_progressive_field; bool supports_interlacing; } _timing;