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Implements SMS2-style addressing if in a 224 or 240-line mode.

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This isn't quite accurate, but it'll do for development.
This commit is contained in:
Thomas Harte 2018-10-23 20:30:08 -04:00
parent 2cbd28478d
commit 90fbad0f1c
1 changed files with 15 additions and 8 deletions
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23
Components/9918/Implementation/9918Base.hpp
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@ -647,12 +647,12 @@ class Base {
#define sprite_fetch(sprite) {\
line_buffer.active_sprites[sprite].x = \
ram_[\
sprite_attribute_table_address_ & size_t(0x3f80 | (line_buffer.active_sprites[sprite].index << 1))\
sprite_attribute_table_address & size_t(0x3f80 | (line_buffer.active_sprites[sprite].index << 1))\
] - (master_system_.shift_sprites_8px_left ? 8 : 0); \
const uint8_t name = ram_[\
sprite_attribute_table_address_ & size_t(0x3f81 | (line_buffer.active_sprites[sprite].index << 1))\
sprite_attribute_table_address & size_t(0x3f81 | (line_buffer.active_sprites[sprite].index << 1))\
] & (sprites_16x16_ ? ~1 : ~0);\
const size_t graphic_location = sprite_generator_table_address_ & size_t(0x2000 | (name << 5) | (line_buffer.active_sprites[sprite].row << 2)); \
const size_t graphic_location = sprite_generator_table_address & size_t(0x2000 | (name << 5) | (line_buffer.active_sprites[sprite].row << 2)); \
line_buffer.active_sprites[sprite].image[0] = ram_[graphic_location]; \
line_buffer.active_sprites[sprite].image[1] = ram_[graphic_location+1]; \
line_buffer.active_sprites[sprite].image[2] = ram_[graphic_location+2]; \
@ -671,8 +671,8 @@ class Base {
#define sprite_y_read(location, sprite) \
slot(location): \
posit_sprite(sprite_selection_buffer, sprite, ram_[sprite_attribute_table_address_ & ((sprite) | 0x3f00)], write_pointer_.row); \
posit_sprite(sprite_selection_buffer, sprite+1, ram_[sprite_attribute_table_address_ & ((sprite + 1) | 0x3f00)], write_pointer_.row); \
posit_sprite(sprite_selection_buffer, sprite, ram_[sprite_attribute_table_address & ((sprite) | 0x3f00)], write_pointer_.row); \
posit_sprite(sprite_selection_buffer, sprite+1, ram_[sprite_attribute_table_address & ((sprite + 1) | 0x3f00)], write_pointer_.row); \
#define fetch_tile_name(column, row_info) {\
const size_t scrolled_column = (column - horizontal_offset) & 0x1f;\
@ -718,20 +718,27 @@ class Base {
LineBuffer &sprite_selection_buffer = line_buffers_[(write_pointer_.row + 1) % mode_timing_.total_lines];
const int horizontal_offset = (write_pointer_.row >= 16 || !master_system_.horizontal_scroll_lock) ? (line_buffer.latched_horizontal_scroll >> 3) : 0;
// Limit address bits in use if this is a SMS2 mode.
const bool is_tall_mode = mode_timing_.pixel_lines != 192;
const size_t pattern_name_address = pattern_name_address_ | (is_tall_mode ? 0xc00 : 0);
const size_t pattern_name_offset = is_tall_mode ? 0x100 : 0;
const size_t sprite_attribute_table_address = sprite_attribute_table_address_ | (is_tall_mode ? 0x80 : 0);
const size_t sprite_generator_table_address = sprite_generator_table_address_ | (is_tall_mode ? 0x1800 : 0);
// Determine row info for the screen both (i) if vertical scrolling is applied; and (ii) if it isn't.
// The programmer can opt out of applying vertical scrolling to the right-hand portion of the display.
const int scrolled_row = (write_pointer_.row + master_system_.latched_vertical_scroll) % 224;
const int scrolled_row = (write_pointer_.row + master_system_.latched_vertical_scroll) % (is_tall_mode ? 256 : 224);
struct RowInfo {
size_t pattern_address_base;
size_t sub_row[2];
};
const RowInfo scrolled_row_info = {
pattern_name_address_ & static_cast<size_t>(((scrolled_row & ~7) << 3) | 0x3800),
pattern_name_address & size_t(((scrolled_row & ~7) << 3) | 0x3800) - pattern_name_offset,
{static_cast<size_t>((scrolled_row & 7) << 2), 28 ^ static_cast<size_t>((scrolled_row & 7) << 2)}
};
RowInfo row_info;
if(master_system_.vertical_scroll_lock) {
row_info.pattern_address_base = pattern_name_address_ & static_cast<size_t>(((write_pointer_.row & ~7) << 3) | 0x3800);
row_info.pattern_address_base = pattern_name_address & size_t(((write_pointer_.row & ~7) << 3) | 0x3800) - pattern_name_offset;
row_info.sub_row[0] = size_t((write_pointer_.row & 7) << 2);
row_info.sub_row[1] = 28 ^ size_t((write_pointer_.row & 7) << 2);
} else row_info = scrolled_row_info;