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Implement extended colour, sprite and RAM pointers.

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This commit is contained in:
Thomas Harte 2023-01-21 20:45:23 -05:00
parent 13e490e7d7
commit c9734df65c
2 changed files with 19 additions and 9 deletions
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26
Components/9918/Implementation/9918.cpp
View File

@ -591,15 +591,22 @@ void Base<personality>::commit_register(int reg, uint8_t value) {
break;
case 3:
colour_table_address_ = size_t(value << 6) | 0x3f;
colour_table_address_ =
(colour_table_address_ & ~0x3fc0) |
(value << 6) |
0x3f;
break;
case 4:
pattern_generator_table_address_ = size_t((value & 0x07) << 11) | 0x7ff;
// TODO: don't mask off so many bits for, at least, the Yamahas.
break;
case 5:
sprite_attribute_table_address_ = size_t((value & 0x7f) << 7) | 0x7f;
sprite_attribute_table_address_ =
(sprite_attribute_table_address_ & ~0x3d80) |
((value << 7) & 0x3f80) |
0x7f;
break;
case 6:
@ -710,12 +717,16 @@ void Base<personality>::commit_register(int reg, uint8_t value) {
break;
case 10:
LOG("TODO: Yamaha colour table high bits; " << PADHEX(2) << +value);
colour_table_address_ =
(colour_table_address_ & ~0x1c000) |
((value << 14) & 0x1c000);
// b0–b2: A14–A16 of the colour table.
break;
case 11:
LOG("TODO: Yamaha sprite table high bits; " << PADHEX(2) << +value);
sprite_attribute_table_address_ =
(sprite_attribute_table_address_ & ~0x18000) |
((value << 15) & 0x18000);
// b0–b1: A15–A16 of the sprite table.
break;
@ -731,8 +742,7 @@ void Base<personality>::commit_register(int reg, uint8_t value) {
break;
case 14:
LOG("TODO: Yamaha A14–A16 selection; " << PADHEX(2) << +value);
// b0–b2: A14–A16 of address counter (i.e. ram_pointer_)
ram_pointer_ = (ram_pointer_ & ~0x1c000) | ((value << 14) & 0x1c000);
break;
case 15:
@ -835,13 +845,13 @@ void Base<personality>::write_register(uint8_t value) {
write_phase_ = true;
// The initial write should half update the access pointer.
ram_pointer_ = (ram_pointer_ & 0xff00) | low_write_;
ram_pointer_ = (ram_pointer_ & ~0xff) | low_write_;
return;
}
// The RAM pointer is always set on a second write, regardless of
// whether the caller is intending to enqueue a VDP operation.
ram_pointer_ = (ram_pointer_ & 0x00ff) | uint16_t(value << 8);
ram_pointer_ = (ram_pointer_ & ~0x3f00) | ((value << 8) & 0x3f00);
write_phase_ = false;
if(value & 0x80) {

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

@ -239,7 +239,7 @@ template <Personality personality> struct Base: public Storage<personality> {
std::array<uint8_t, memory_size(personality)> ram_;
// State of the DRAM/CRAM-access mechanism.
uint16_t ram_pointer_ = 0;
size_t ram_pointer_ = 0;
uint8_t read_ahead_buffer_ = 0;
MemoryAccess queued_access_ = MemoryAccess::None;
int cycles_until_access_ = 0;