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Doubles down on address-storage format, and implements the vertical scrolling lock.

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Thomas Harte
2018-10-07 18:55:35 -04:00
parent 24644f1dd1
commit 6975ed22c0
2 changed files with 59 additions and 39 deletions
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62
Components/9918/Implementation/9918Base.hpp
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@@ -276,8 +276,6 @@ class Base {
void do_external_slot() {
// TODO: write or read a value if one is queued and ready to read/write.
// (and, later: update the command engine, if this is an MSX2).
switch(queued_access_) {
default: return;
@@ -427,8 +425,8 @@ class Base {
fetch_columns_4(location, column); \
fetch_columns_4(location+12, column+4);
const size_t row_base = pattern_name_address_ + static_cast<size_t>(row_ >> 3) * 40;
const size_t row_offset = pattern_generator_table_address_ + (row_ & 7);
const size_t row_base = pattern_name_address_ & static_cast<size_t>(row_ >> 3) * 40;
const size_t row_offset = pattern_generator_table_address_ & (row_ & 7);
switch(start) {
default:
@@ -610,13 +608,13 @@ class Base {
posit_sprite(sprite, ram_[sprite_attribute_table_address_ & (sprite | 0x3f00)], row_); \
posit_sprite(sprite+1, ram_[sprite_attribute_table_address_ & ((sprite + 1) | 0x3f00)], row_); \
#define fetch_tile_name(column) {\
#define fetch_tile_name(column, row_info) {\
const size_t scrolled_column = (column - horizontal_offset) & 0x1f;\
const size_t address = pattern_address_base + (scrolled_column << 1); \
const size_t address = row_info.pattern_address_base + (scrolled_column << 1); \
master_system_.names[column].flags = ram_[address+1]; \
master_system_.names[column].offset = static_cast<size_t>( \
(((master_system_.names[column].flags&1) << 8) | ram_[address]) << 5 \
) + sub_row[(master_system_.names[column].flags&4) >> 2]; \
) + row_info.sub_row[(master_system_.names[column].flags&4) >> 2]; \
}
#define fetch_tile(column) \
@@ -625,36 +623,52 @@ class Base {
master_system_.tile_graphics[column][2] = ram_[master_system_.names[column].offset+2]; \
master_system_.tile_graphics[column][3] = ram_[master_system_.names[column].offset+3];
#define background_fetch_block(location, column, sprite) \
slot(location): fetch_tile_name(column) \
#define background_fetch_block(location, column, sprite, row_info) \
slot(location): fetch_tile_name(column, row_info) \
external_slot(location+1); \
slot(location+2): \
slot(location+3): \
slot(location+4): \
fetch_tile(column) \
fetch_tile_name(column+1) \
fetch_tile_name(column+1, row_info) \
sprite_y_read(location+5, sprite); \
slot(location+6): \
slot(location+7): \
slot(location+8): \
fetch_tile(column+1) \
fetch_tile_name(column+2) \
fetch_tile_name(column+2, row_info) \
sprite_y_read(location+9, sprite+2); \
slot(location+10): \
slot(location+11): \
slot(location+12): \
fetch_tile(column+2) \
fetch_tile_name(column+3) \
fetch_tile_name(column+3, row_info) \
sprite_y_read(location+13, sprite+4); \
slot(location+14): \
slot(location+15): fetch_tile(column+3)
const int scrolled_row = (row_ + master_system_.vertical_scroll) % 224;
const size_t pattern_address_base = (pattern_name_address_ | size_t(0x3ff)) & static_cast<size_t>(((scrolled_row & ~7) << 3) | 0x3800);
const size_t sub_row[2] = {static_cast<size_t>((scrolled_row & 7) << 2), 28 ^ static_cast<size_t>((scrolled_row & 7) << 2)};
// Determine the coarse horizontal scrolling offset; this isn't applied on the first two lines if the programmer has requested it.
const int horizontal_offset = (row_ >= 16 || !master_system_.horizontal_scroll_lock) ? (master_system_.horizontal_scroll >> 3) : 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 = (row_ + master_system_.vertical_scroll) % 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),
{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>(((row_ & ~7) << 3) | 0x3800);
row_info.sub_row[0] = size_t((row_ & 7) << 2);
row_info.sub_row[1] = 28 ^ size_t((row_ & 7) << 2);
} else row_info = scrolled_row_info;
// ... and do the actual fetching, which follows this routine:
switch(start) {
default:
external_slots_4(0);
@@ -682,14 +696,14 @@ class Base {
sprite_y_read(41, 12);
sprite_y_read(42, 14);
background_fetch_block(43, 0, 16);
background_fetch_block(59, 4, 22);
background_fetch_block(75, 8, 28);
background_fetch_block(91, 12, 34);
background_fetch_block(107, 16, 40);
background_fetch_block(123, 20, 46);
background_fetch_block(139, 24, 52); // TODO: this and the next one should ignore master_system_.vertical_scroll.
background_fetch_block(156, 28, 58);
background_fetch_block(43, 0, 16, scrolled_row_info);
background_fetch_block(59, 4, 22, scrolled_row_info);
background_fetch_block(75, 8, 28, scrolled_row_info);
background_fetch_block(91, 12, 34, scrolled_row_info);
background_fetch_block(107, 16, 40, scrolled_row_info);
background_fetch_block(123, 20, 46, scrolled_row_info);
background_fetch_block(139, 24, 52, row_info);
background_fetch_block(156, 28, 58, row_info);
return;
}