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Correct sprite attribute and colour table addresses.

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This commit is contained in:
Thomas Harte 2023-02-21 19:34:26 -05:00
parent a28b5bdeea
commit 091c1b0f45
1 changed files with 33 additions and 12 deletions
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45
Components/9918/Implementation/Fetch.hpp
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@ -199,6 +199,16 @@ class SpriteFetcher {
public:
using AddressT = typename Base<personality>::AddressT;
// The Yamaha VDP adds an additional table when in Sprite Mode 2, the sprite colour
// table, which is intended to fill the 512 bytes before the programmer-located sprite
// attribute table.
//
// It partially enforces this proximity by forcing bits 7 and 8 to 0 in the address of
// the attribute table, and forcing them to 1 but masking out bit 9 for the colour table.
//
// AttributeAddressMask is used to enable or disable that behaviour.
static constexpr AddressT AttributeAddressMask = (mode == SpriteMode::Mode2) ? AddressT(~0x180) : AddressT(~0x000);
SpriteFetcher(Base<personality> *base, LineBuffer &buffer, LineBuffer &sprite_selection_buffer, int y) :
base(base),
tile_buffer(buffer),
@ -230,46 +240,57 @@ class SpriteFetcher {
}
void fetch_y(int sprite) {
base->posit_sprite(sprite_selection_buffer, sprite, base->ram_[base->sprite_attribute_table_address_ & bits<7>(AddressT(sprite << 2))], y);
const AddressT address = base->sprite_attribute_table_address_ & AttributeAddressMask & bits<7>(AddressT(sprite << 2));
const uint8_t sprite_y = base->ram_[address];
base->posit_sprite(sprite_selection_buffer, sprite, sprite_y, y);
}
private:
void fetch_xy(int slot) {
tile_buffer.active_sprites[slot].x =
base->ram_[
base->sprite_attribute_table_address_ & bits<7>(AddressT((tile_buffer.active_sprites[slot].index << 2) | 1))
base->sprite_attribute_table_address_ & AttributeAddressMask & bits<7>(AddressT((tile_buffer.active_sprites[slot].index << 2) | 1))
];
}
uint8_t name(int slot) {
return base->ram_[
base->sprite_attribute_table_address_ & bits<7>(AddressT((tile_buffer.active_sprites[slot].index << 2) | 2))
] & (base->sprites_16x16_ ? ~3 : ~0);
const AddressT address =
base->sprite_attribute_table_address_ &
AttributeAddressMask &
bits<7>(AddressT((tile_buffer.active_sprites[slot].index << 2) | 2));
const uint8_t name = base->ram_[address] & (base->sprites_16x16_ ? ~3 : ~0);
return name;
}
void fetch_image(int slot, uint8_t name) {
uint8_t colour = 0;
auto &sprite = tile_buffer.active_sprites[slot];
switch(mode) {
case SpriteMode::Mode1:
// Fetch colour from the attribute table, per this sprite's slot.
colour = base->ram_[
base->sprite_attribute_table_address_ & bits<7>(AddressT((tile_buffer.active_sprites[slot].index << 2) | 3))
base->sprite_attribute_table_address_ & bits<7>(AddressT((sprite.index << 2) | 3))
];
break;
case SpriteMode::Mode2: {
// Fetch colour from the colour table, per this sprite's slot and row.
const AddressT colour_table_address = (base->sprite_attribute_table_address_ | ~AttributeAddressMask) & AddressT(~0x200);
colour = base->ram_[
base->sprite_attribute_table_address_ & AddressT(~512) & bits<7>(AddressT((tile_buffer.active_sprites[slot].index << 4) | tile_buffer.active_sprites[slot].row))
colour_table_address &
bits<9>(
AddressT(sprite.index << 4) |
AddressT(sprite.row)
)
];
} break;
}
tile_buffer.active_sprites[slot].image[2] = colour;
tile_buffer.active_sprites[slot].x -= (colour & 0x80) >> 2;
sprite.image[2] = colour;
sprite.x -= (colour & 0x80) >> 2;
const AddressT graphic_location = base->sprite_generator_table_address_ & bits<11>(AddressT((name << 3) | tile_buffer.active_sprites[slot].row));
tile_buffer.active_sprites[slot].image[0] = base->ram_[graphic_location];
tile_buffer.active_sprites[slot].image[1] = base->ram_[graphic_location+16];
const AddressT graphic_location = base->sprite_generator_table_address_ & bits<11>(AddressT((name << 3) | sprite.row));
sprite.image[0] = base->ram_[graphic_location];
sprite.image[1] = base->ram_[graphic_location+16];
}
Base<personality> *const base;