forked from suyu/suyu
thread: updated Reschedule to sit at a synchronization barrier when no other threads are ready for execution
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1 changed files with 18 additions and 0 deletions
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@ -323,11 +323,29 @@ void Reschedule() {
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Thread* prev = GetCurrentThread();
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Thread* prev = GetCurrentThread();
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Thread* next = NextThread();
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Thread* next = NextThread();
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if (next > 0) {
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if (next > 0) {
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INFO_LOG(KERNEL, "context switch 0x%08X -> 0x%08X", prev->GetHandle(), next->GetHandle());
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SwitchContext(next);
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SwitchContext(next);
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// Hack - automatically change previous thread (which would have been in "wait" state) to
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// Hack - automatically change previous thread (which would have been in "wait" state) to
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// "ready" state, so that we can immediately resume to it when new thread yields. FixMe to
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// "ready" state, so that we can immediately resume to it when new thread yields. FixMe to
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// actually wait for whatever event it is supposed to be waiting on.
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// actually wait for whatever event it is supposed to be waiting on.
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ChangeReadyState(prev, true);
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} else {
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INFO_LOG(KERNEL, "no ready threads, staying on 0x%08X", prev->GetHandle());
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// Hack - no other threads are available, so decrement current PC to the last instruction,
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// and then resume current thread. This should always be called on a blocking instruction
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// (e.g. svcWaitSynchronization), and the result should be that the instruction is repeated
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// until it no longer blocks.
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// TODO(bunnei): A better solution: Have the CPU switch to an idle thread
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ThreadContext ctx;
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SaveContext(ctx);
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ctx.pc -= 4;
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LoadContext(ctx);
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ChangeReadyState(prev, true);
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ChangeReadyState(prev, true);
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}
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}
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}
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}
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