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Imagines a future of being able to boot into the BIOS.

This commit is contained in:
Thomas Harte 2020-04-29 22:07:20 -04:00
parent f899af0eef
commit 1f34214fb3
2 changed files with 17 additions and 3 deletions
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15
Machines/MasterSystem/MasterSystem.cpp
View File

@ -117,7 +117,9 @@ class ConcreteMachine:
map(write_pointers_, nullptr, 0x10000, 0);
// Take a copy of the cartridge and place it into memory.
cartridge_ = target.media.cartridges[0]->get_segments()[0].data;
if(!target.media.cartridges.empty()) {
cartridge_ = target.media.cartridges[0]->get_segments()[0].data;
}
if(cartridge_.size() < 48*1024) {
std::size_t new_space = 48*1024 - cartridge_.size();
cartridge_.resize(48*1024);
@ -138,7 +140,15 @@ class ConcreteMachine:
//
// 0072ed54 = US/European BIOS 1.3
// 48d44a13 = Japanese BIOS 2.1
const auto roms = rom_fetcher({ {"MasterSystem", "the Master System BIOS", "bios.sms", 8*1024, { 0x0072ed54, 0x48d44a13 } } });
const bool is_japanese = target.region == Target::Region::Japan;
const auto roms = rom_fetcher(
{ {"MasterSystem",
is_japanese ? "the Japanese Master System BIOS" : "the European/US Master System BIOS",
is_japanese ? "japanese-bios.sms" : "bios.sms",
8*1024,
{ is_japanese ? 0x48d44a13u : 0x0072ed54u }
} }
);
if(!roms[0]) {
// No BIOS found; attempt to boot as though it has already disabled itself.
memory_control_ |= 0x08;
@ -160,6 +170,7 @@ class ConcreteMachine:
}
// Apply a relatively low low-pass filter. More guidance needed here.
// TODO: this is disabled for now since it isn't applicable for the FM chip, I think.
// speaker_.set_high_frequency_cutoff(8000);
// Set default mixer levels: FM off, SN full-throttle.

5
ROMImages/MasterSystem/readme.txt
View File

@ -2,4 +2,7 @@ BIOS files would ordinarily go here; the copyright status of these is uncertain
Expected files:
bios.sms — the EU/US Master System BIOS.
bios.sms — the EU/US Master System BIOS.
japanese-bios.sms — the Japanese Master System BIOS.
If the file sought by the emulator is missing, it will attempt to boot a game without using the BIOS.