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Merge pull request #329 from TomHarte/TMSTopLine

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Corrects bad TMS sprite selections on the top row of the screen.
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Thomas Harte 2018-01-06 13:26:33 -08:00 committed by GitHub
commit 772c320d5a
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 9 additions and 8 deletions
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15
Components/9918/9918.cpp
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@ -76,7 +76,7 @@ Outputs::CRT::CRT *TMS9918::get_crt() {
return crt_.get();
}
void TMS9918Base::test_sprite(int sprite_number) {
void TMS9918Base::test_sprite(int sprite_number, int screen_row) {
if(!(status_ & StatusFifthSprite)) {
status_ = static_cast<uint8_t>((status_ & ~31) | sprite_number);
}
@ -90,7 +90,7 @@ void TMS9918Base::test_sprite(int sprite_number) {
return;
}
const int sprite_row = (row_ - sprite_position)&255;
const int sprite_row = (screen_row - sprite_position)&255;
if(sprite_row < 0 || sprite_row >= sprite_height_) return;
const int active_sprite_slot = sprite_sets_[active_sprite_set_].active_sprite_slot;
@ -126,7 +126,7 @@ void TMS9918Base::get_sprite_contents(int field, int cycles_left, int screen_row
field = std::min(4, final_field);
const int sprite_offset = sprite.info[2] & ~(sprites_16x16_ ? 3 : 0);
const int sprite_address = sprite_generator_table_address_ + (sprite_offset << 3) + sprite.row;
const int sprite_address = sprite_generator_table_address_ + (sprite_offset << 3) + sprite.row; // TODO: recalclate sprite.row from screen_row (?)
while(field < final_field) {
sprite.image[field - 4] = ram_[sprite_address + ((field - 4) << 4)];
field++;
@ -211,6 +211,7 @@ void TMS9918::run_for(const HalfCycles cycles) {
// Perform video memory accesses.
// ------------------------------
if(((row_ < 192) || (row_ == frame_lines_-1)) && !blank_screen_) {
const int sprite_row = (row_ < 192) ? row_ : -1;
const int access_slot = column_ >> 1; // There are only 171 available memory accesses per line.
switch(line_mode_) {
default: break;
@ -243,7 +244,7 @@ void TMS9918::run_for(const HalfCycles cycles) {
// Then ten access windows are filled with collection of sprite 3 and 4 details.
if(access_pointer_ >= 5 && access_pointer_ < 15) {
int end = std::min(15, access_slot);
get_sprite_contents(access_pointer_ - 5 + 14, end - access_pointer_, row_ - 1);
get_sprite_contents(access_pointer_ - 5 + 14, end - access_pointer_, sprite_row - 1);
access_pointer_ = std::min(15, access_slot);
}
@ -261,7 +262,7 @@ void TMS9918::run_for(const HalfCycles cycles) {
// Then eight access windows fetch the y position for the first eight sprites.
while(access_pointer_ < 27 && access_pointer_ < access_slot) {
test_sprite(access_pointer_ - 19);
test_sprite(access_pointer_ - 19, sprite_row);
access_pointer_++;
}
@ -308,7 +309,7 @@ void TMS9918::run_for(const HalfCycles cycles) {
const int sprite_end = (end - 28 + 3) >> 2;
for(int column = sprite_start; column < sprite_end; ++column) {
if(column&3) {
test_sprite(7 + column - (column >> 2));
test_sprite(7 + column - (column >> 2), sprite_row);
}
}
@ -322,7 +323,7 @@ void TMS9918::run_for(const HalfCycles cycles) {
// Fourteen access windows: collect initial sprite information.
if(access_pointer_ >= 157 && access_pointer_ < 171) {
int end = std::min(171, access_slot);
get_sprite_contents(access_pointer_ - 157, end - access_pointer_, row_);
get_sprite_contents(access_pointer_ - 157, end - access_pointer_, sprite_row);
access_pointer_ = std::min(171, access_slot);
}
break;

2
Components/9918/Implementation/9918Base.hpp
View File

@ -92,7 +92,7 @@ class TMS9918Base {
int access_pointer_ = 0;
inline void test_sprite(int sprite_number);
inline void test_sprite(int sprite_number, int screen_row);
inline void get_sprite_contents(int start, int cycles, int screen_row);
};