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CDROM: Simulate backwards 1T jump on short seeks 

Fixes hangs in LMA Manager, Nightmare Creatures PAL with Interpreter.
This commit is contained in:
Stenzek 2024-09-25 01:10:50 +10:00
parent 3808217298
commit 114effd9a1
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1 changed files with 47 additions and 35 deletions
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82
src/core/cdrom.cpp
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@ -312,6 +312,7 @@ static TickCount GetTicksForStop(bool motor_was_on);
static TickCount GetTicksForSpeedChange();
static TickCount GetTicksForTOCRead();
static CDImage::LBA GetNextSectorToBeRead();
static u32 GetSectorsPerTrack(CDImage::LBA lba);
static bool CompleteSeek();
static void BeginCommand(Command command); // also update status register
@ -1440,6 +1441,12 @@ TickCount CDROM::GetTicksForRead()
return s_mode.double_speed ? (tps / 150) : (tps / 75);
}
u32 CDROM::GetSectorsPerTrack(CDImage::LBA lba)
{
return static_cast<CDImage::LBA>(9.0f +
2.5440497f * std::log(static_cast<float>(lba / CDImage::FRAMES_PER_MINUTE) + 1u));
}
TickCount CDROM::GetTicksForSeek(CDImage::LBA new_lba, bool ignore_speed_change)
{
static constexpr TickCount MIN_TICKS = 30000;
@ -1456,7 +1463,7 @@ TickCount CDROM::GetTicksForSeek(CDImage::LBA new_lba, bool ignore_speed_change)
UpdatePhysicalPosition(false);
const CDImage::LBA current_lba = IsMotorOn() ? (IsSeeking() ? s_seek_end_lba : s_physical_lba) : 0;
const u32 lba_diff = static_cast<u32>((new_lba > current_lba) ? (new_lba - current_lba) : (current_lba - new_lba));
const CDImage::LBA lba_diff = ((new_lba > current_lba) ? (new_lba - current_lba) : (current_lba - new_lba));
// Motor spin-up time.
if (!IsMotorOn())
@ -1468,15 +1475,28 @@ TickCount CDROM::GetTicksForSeek(CDImage::LBA new_lba, bool ignore_speed_change)
}
float seconds;
if (current_lba < new_lba && lba_diff < 10)
std::string_view seek_type;
if (lba_diff < 10)
{
// If we're behind the current sector, and within a small distance, the mech just waits for the sector to come up by
// reading normally (or apparently moves the lens according to some?). This timing is actually needed for
// Transformers - Beast Wars Transmetals, it gets very unstable during loading if seeks are too fast.
const u32 ticks_per_sector =
s_mode.double_speed ? static_cast<u32>(System::MASTER_CLOCK / 150) : static_cast<u32>(System::MASTER_CLOCK / 75);
ticks += ticks_per_sector * std::min<u32>(5u, lba_diff);
seconds = 0.0f;
const TickCount ticks_per_sector = s_mode.double_speed ? (System::MASTER_CLOCK / 150) : (System::MASTER_CLOCK / 75);
if (current_lba < new_lba)
{
// If we're behind the current sector, and within a small distance, the mech just waits for the sector to come up
// by reading normally (or apparently moves the lens according to some?). This timing is actually needed for
// Transformers - Beast Wars Transmetals, it gets very unstable during loading if seeks are too fast.
ticks += ticks_per_sector * std::min(8u, lba_diff);
seek_type = "forward";
}
else
{
// Track jump back. We cap this at 8 sectors (~53ms), so it doesn't take longer than the medium seek below.
const CDImage::LBA sectors_per_track = GetSectorsPerTrack(current_lba);
const CDImage::LBA tjump_position = (current_lba >= sectors_per_track) ? (current_lba - sectors_per_track) : 0;
ticks += ticks_per_sector * std::clamp((new_lba - std::min(new_lba, tjump_position)), 1u, 8u);
seek_type = "1T back+forward";
}
}
else if (lba_diff < 7200)
{
@ -1487,6 +1507,7 @@ TickCount CDROM::GetTicksForSeek(CDImage::LBA new_lba, bool ignore_speed_change)
(-63.1333f * std::log(std::clamp(static_cast<float>(current_lba) / static_cast<float>(CDImage::FRAMES_PER_MINUTE),
1.0f, 72.0f))));
seconds = (lba_diff < switch_point) ? 0.05f : 0.1f;
seek_type = (new_lba > current_lba) ? "NT forward" : "NT backward";
}
else
{
@ -1500,6 +1521,7 @@ TickCount CDROM::GetTicksForSeek(CDImage::LBA new_lba, bool ignore_speed_change)
SLED_FIXED_COST +
(((SLED_VARIABLE_COST * (std::log(static_cast<float>(lba_diff)) / std::log(MAX_SLED_LBA)))) * LOG_WEIGHT) +
((SLED_VARIABLE_COST * (lba_diff / MAX_SLED_LBA)) * (1.0f - LOG_WEIGHT));
seek_type = (new_lba > current_lba) ? "2N/sled forward" : "2N/sled backward";
}
constexpr u32 ticks_per_second = static_cast<u32>(System::MASTER_CLOCK);
@ -1514,13 +1536,15 @@ TickCount CDROM::GetTicksForSeek(CDImage::LBA new_lba, bool ignore_speed_change)
const TickCount remaining_change_ticks = s_drive_event.GetTicksUntilNextExecution();
ticks += remaining_change_ticks;
DEV_LOG("Seek time for {} LBAs: {} ({:.3f} ms) ({} for speed change/implicit TOC read)", lba_diff, ticks,
(static_cast<float>(ticks) / static_cast<float>(ticks_per_second)) * 1000.0f, remaining_change_ticks);
DEV_LOG("Seek time for {}->{} ({} LBA): {} ({:.3f} ms) ({} for speed change/init) ({})",
LBAToMSFString(current_lba), LBAToMSFString(new_lba), lba_diff, ticks,
(static_cast<float>(ticks) / static_cast<float>(ticks_per_second)) * 1000.0f, remaining_change_ticks,
seek_type);
}
else
{
DEV_LOG("Seek time for {} LBAs: {} ({:.3f} ms)", lba_diff, ticks,
(static_cast<float>(ticks) / static_cast<float>(ticks_per_second)) * 1000.0f);
DEV_LOG("Seek time for {}->{} ({} LBA): {} ({:.3f} ms) ({})", LBAToMSFString(current_lba), LBAToMSFString(new_lba),
lba_diff, ticks, (static_cast<float>(ticks) / static_cast<float>(ticks_per_second)) * 1000.0f, seek_type);
}
return System::ScaleTicksToOverclock(static_cast<TickCount>(ticks));
@ -2703,33 +2727,17 @@ void CDROM::UpdatePhysicalPosition(bool update_logical)
const u32 carry = diff % ticks_per_read;
if (sector_diff > 0)
{
CDImage::LBA hold_offset;
CDImage::LBA sectors_per_track;
// hardware tests show that it holds much closer to the target sector in logical mode
if (s_last_sector_header_valid)
{
hold_offset = 2;
sectors_per_track = 4;
}
else
{
hold_offset = 0;
sectors_per_track =
static_cast<CDImage::LBA>(7.0f + 2.811844405f * std::log(static_cast<float>(s_current_lba / 4500u) + 1u));
}
const CDImage::LBA hold_offset = s_last_sector_header_valid ? 2 : 0;
const CDImage::LBA sectors_per_track = GetSectorsPerTrack(s_current_lba);
const CDImage::LBA hold_position = s_current_lba + hold_offset;
const CDImage::LBA base =
(hold_position >= (sectors_per_track - 1)) ? (hold_position - (sectors_per_track - 1)) : hold_position;
if (s_physical_lba < base)
s_physical_lba = base;
const CDImage::LBA old_offset = s_physical_lba - base;
const CDImage::LBA tjump_position = (hold_position >= sectors_per_track) ? (hold_position - sectors_per_track) : 0;
const CDImage::LBA old_offset = s_physical_lba - tjump_position;
const CDImage::LBA new_offset = (old_offset + sector_diff) % sectors_per_track;
const CDImage::LBA new_physical_lba = base + new_offset;
const CDImage::LBA new_physical_lba = tjump_position + new_offset;
#ifdef _DEBUG
DEV_LOG("Tick diff {}, sector diff {}, old pos {}, new pos {}", diff, sector_diff, LBAToMSFString(s_physical_lba),
DEV_LOG("{} sectors @ {} SPT, old pos {}, hold pos {}, tjump pos {}, new pos {}", sector_diff, sectors_per_track,
LBAToMSFString(s_physical_lba), LBAToMSFString(hold_position), LBAToMSFString(tjump_position),
LBAToMSFString(new_physical_lba));
#endif
if (s_physical_lba != new_physical_lba)
@ -2849,6 +2857,10 @@ void CDROM::DoSeekComplete(TickCount ticks_late)
const bool seek_okay = CompleteSeek();
if (seek_okay)
{
DEV_LOG("{} seek to [{}] complete{}", logical ? "Logical" : "Physical",
LBAToMSFString(s_reader.GetLastReadSector()),
s_read_after_seek ? ", now reading" : (s_play_after_seek ? ", now playing" : ""));
// seek complete, transition to play/read if requested
// INT2 is not sent on play/read
if (s_read_after_seek)