From 000a7f05c9ca8e6ed74dd4bc0486474b99270d97 Mon Sep 17 00:00:00 2001
From: plutoo <plutoo@universe>
Date: Tue, 30 Jan 2018 22:39:02 +0100
Subject: [PATCH] Experimental implementation of condvars

---
 nx/include/switch/kernel/cond_var.h | 18 ++++++++++++++
 nx/include/switch/kernel/svc.h      |  2 ++
 nx/source/kernel/cond_var.c         | 37 +++++++++++++++++++++++++++++
 nx/source/kernel/svc.s              | 10 ++++++++
 4 files changed, 67 insertions(+)
 create mode 100644 nx/include/switch/kernel/cond_var.h
 create mode 100644 nx/source/kernel/cond_var.c

diff --git a/nx/include/switch/kernel/cond_var.h b/nx/include/switch/kernel/cond_var.h
new file mode 100644
index 00000000..8b56be2e
--- /dev/null
+++ b/nx/include/switch/kernel/cond_var.h
@@ -0,0 +1,18 @@
+// Copyright 2018 plutoo
+#include "../types.h"
+#include "../kernel/mutex.h"
+
+typedef struct {
+    u32    tag;
+    Mutex* mutex;
+} CondVar;
+
+void condvarInit(CondVar* c, Mutex* m);
+
+// When the wait-functions return, the mutex is acquired.
+void condvarWaitTimeout(CondVar* c, u64 timeout);
+void condvarWait(CondVar* c);
+
+Result condvarWake(CondVar* c, int num);
+Result condvarWakeOne(CondVar* c);
+Result condvarWakeAll(CondVar* c);
diff --git a/nx/include/switch/kernel/svc.h b/nx/include/switch/kernel/svc.h
index 159eb291..f48f5f45 100644
--- a/nx/include/switch/kernel/svc.h
+++ b/nx/include/switch/kernel/svc.h
@@ -52,6 +52,8 @@ Result svcWaitSynchronization(s32* index, const Handle* handles, s32 handleCount
 Result svcCancelSynchronization(Handle thread);
 Result svcArbitrateLock(u32 wait_tag, u32* tag_location, u32 self_tag);
 Result svcArbitrateUnlock(u32* tag_location);
+Result svcWaitProcessWideKeyAtomic(u32* key, u32* tag_location, u32 self_tag, u64 timeout);
+Result svcSignalProcessWideKey(u32* key, s32 num);
 Result svcConnectToNamedPort(Handle* session, const char* name);
 u64    svcGetSystemTick(void);
 Result svcSendSyncRequest(Handle session);
diff --git a/nx/source/kernel/cond_var.c b/nx/source/kernel/cond_var.c
new file mode 100644
index 00000000..e8029fa8
--- /dev/null
+++ b/nx/source/kernel/cond_var.c
@@ -0,0 +1,37 @@
+// Copyright 2018 plutoo
+#include "types.h"
+#include "result.h"
+#include "kernel/svc.h"
+#include "kernel/cond_var.h"
+#include "../internal.h"
+
+void condvarInit(CondVar* c, Mutex* m) {
+    c->tag = 0;
+    c->mutex = m;
+}
+
+void condvarWaitTimeout(CondVar* c, u64 timeout) {
+    Result rc;
+
+    rc = svcWaitProcessWideKeyAtomic(&c->tag, (u32*) c->mutex, getThreadVars()->handle, timeout);
+
+    // On timeout, we need to acquire it manually.
+    if (rc == 0xEA01)
+        mutexLock(c->mutex);
+}
+
+void condvarWait(CondVar* c) {
+    return condvarWaitTimeout(c, -1);
+}
+
+Result condvarWake(CondVar* c, int num) {
+    return svcSignalProcessWideKey((u32*) &c->tag, num);
+}
+
+Result condvarWakeOne(CondVar* c) {
+    return condvarWake(c, 1);
+}
+
+Result condvarWakeAll(CondVar* c) {
+    return condvarWake(c, -1);
+}
diff --git a/nx/source/kernel/svc.s b/nx/source/kernel/svc.s
index 6be5ef33..7681c889 100644
--- a/nx/source/kernel/svc.s
+++ b/nx/source/kernel/svc.s
@@ -122,6 +122,16 @@ SVC_BEGIN svcArbitrateUnlock
 	ret
 SVC_END
 
+SVC_BEGIN svcWaitProcessWideKeyAtomic
+	svc 0x1c
+	ret
+SVC_END
+
+SVC_BEGIN svcSignalProcessWideKey
+	svc 0x1d
+	ret
+SVC_END
+
 SVC_BEGIN svcConnectToNamedPort
 	str x0, [sp, #-16]!
 	svc 0x1F