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Merge pull request #9552 from endrift/gba-timing 

SI/DeviceGBA: Fix SI timings to actually closely match hardware
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JMC47 2021-04-26 21:20:06 -04:00 committed by GitHub
parent c09427ccdf 4ce3362bce
commit 4d10023727
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GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 17 additions and 9 deletions
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26
Source/Core/Core/HW/SI/SI_DeviceGBA.cpp
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@ -43,42 +43,50 @@ enum EJoybusCmds
CMD_WRITE = 0x15
};
constexpr auto BITS_PER_SECOND = 115200;
constexpr auto BYTES_PER_SECOND = BITS_PER_SECOND / 8;
constexpr auto GC_BITS_PER_SECOND = 200000;
constexpr auto GBA_BITS_PER_SECOND = 250000;
constexpr auto GC_STOP_BIT_NS = 6500;
constexpr auto GBA_STOP_BIT_NS = 14000;
constexpr auto SEND_MAX_SIZE = 5, RECV_MAX_SIZE = 5;
// --- GameBoy Advance "Link Cable" ---
static int GetTransferTime(u8 cmd)
{
u64 bytes_transferred = 0;
u64 gc_bytes_transferred = 1;
u64 gba_bytes_transferred = 1;
u64 stop_bits_ns = GC_STOP_BIT_NS + GBA_STOP_BIT_NS;
switch (cmd)
{
case CMD_RESET:
case CMD_STATUS:
{
bytes_transferred = 4;
gba_bytes_transferred = 3;
break;
}
case CMD_READ:
{
bytes_transferred = 6;
gba_bytes_transferred = 5;
break;
}
case CMD_WRITE:
{
bytes_transferred = 1;
gc_bytes_transferred = 5;
break;
}
default:
{
bytes_transferred = 1;
gba_bytes_transferred = 0;
break;
}
}
return static_cast<int>(bytes_transferred * SystemTimers::GetTicksPerSecond() /
(std::max(s_num_connected, 1) * BYTES_PER_SECOND));
u64 cycles =
(gba_bytes_transferred * 8 * SystemTimers::GetTicksPerSecond() / GBA_BITS_PER_SECOND) +
(gc_bytes_transferred * 8 * SystemTimers::GetTicksPerSecond() / GC_BITS_PER_SECOND) +
(stop_bits_ns * SystemTimers::GetTicksPerSecond() / 1000000000LL);
return static_cast<int>(cycles);
}
static void GBAConnectionWaiter()