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Cleans up and zooms in on the TMS slightly.

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This commit is contained in:
Thomas Harte 2017-12-02 17:48:31 -05:00
parent fe7fc6b22e
commit e4534775b0
2 changed files with 33 additions and 11 deletions
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43
Components/9918/9918.cpp
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@ -54,6 +54,7 @@ TMS9918::TMS9918(Personality p) :
"return texture(sampler, coordinate).rgb / vec3(255.0);"
"}");
crt_->set_output_device(Outputs::CRT::OutputDevice::Monitor);
crt_->set_visible_area(Outputs::CRT::Rect(0.055f, 0.025f, 0.9f, 0.9f));
}
std::shared_ptr<Outputs::CRT::CRT> TMS9918::get_crt() {
@ -82,14 +83,23 @@ void TMS9918::run_for(const HalfCycles cycles) {
// 26 cycles sync;
while(int_cycles) {
// Determine how much time has passed in the remainder of this line, and proceed.
int cycles_left = std::min(342 - column_, int_cycles);
column_ += cycles_left;
int_cycles -= cycles_left;
column_ += cycles_left; // column_ is now the column that has been reached in this line.
int_cycles -= cycles_left; // Count down duration to run for.
// ------------------------------
// TODO: memory access slot here.
// ------------------------------
// ------------------------------
// Perform video memory accesses.
// ------------------------------
if(row_ < 192 && !blank_screen_) {
// ------------------------
// Perform memory accesses.
// ------------------------
const int access_slot = column_ >> 1; // There are only 171 available memory accesses per line.
switch(line_mode_) {
case LineMode::Text:
@ -168,11 +178,17 @@ void TMS9918::run_for(const HalfCycles cycles) {
}
break;
}
// --------------------
// End memory accesses.
// --------------------
}
// --------------------------
// End video memory accesses.
// --------------------------
// --------------------
// Output video stream.
// --------------------
if(row_ < 192 && !blank_screen_) {
// ----------------------
// Output horizontal sync
// ----------------------
@ -267,7 +283,15 @@ void TMS9918::run_for(const HalfCycles cycles) {
output_column_ = column_;
}
}
// -----------------
// End video stream.
// -----------------
// -----------------------------------
// Prepare for next line, potentially.
// -----------------------------------
if(column_ == 342) {
access_pointer_ = column_ = output_column_ = 0;
row_ = (row_ + 1) % frame_lines_;
@ -357,7 +381,6 @@ void TMS9918::set_register(int address, uint8_t value) {
break;
case 7:
text_background_colour_ = low_write_;
text_colour_ = low_write_ >> 4;
background_colour_ = low_write_ & 0xf;
break;
@ -392,7 +415,7 @@ uint8_t TMS9918::get_register(int address) {
HalfCycles TMS9918::get_time_until_interrupt() {
if(!generate_interrupts_) return HalfCycles(-1);
if(get_interrupt_line()) return HalfCycles(-1);
if(get_interrupt_line()) return HalfCycles(0);
const int half_cycles_per_frame = frame_lines_ * 228 * 2;
int half_cycles_remaining = (192 * 228 * 2 + half_cycles_per_frame - half_cycles_into_frame_.as_int()) % half_cycles_per_frame;

1
Components/9918/9918.hpp
View File

@ -74,7 +74,6 @@ class TMS9918 {
uint8_t text_colour_ = 0;
uint8_t background_colour_ = 0;
uint8_t text_background_colour_ = 0;
HalfCycles half_cycles_into_frame_;
int column_ = 0, row_ = 0, output_column_ = 0;