[MIPS] Add atomic routines

Change-Id: I2cb20ce44dd230d222b7fc1ede2e1e3dce6e692b

2 files changed, 104 insertions, 0 deletions

diff --git a/libc/private/bionic_atomic_inline.h b/libc/private/bionic_atomic_inline.h
index 821ad39..0b348c3 100644
--- a/libc/private/bionic_atomic_inline.h
+++ b/libc/private/bionic_atomic_inline.h
@@ -53,6 +53,8 @@ extern "C" {
 #  include <bionic_atomic_arm.h>
 #elif defined(__i386__)
 #  include <bionic_atomic_x86.h>
+#elif defined(__mips__)
+#  include <bionic_atomic_mips.h>
 #else
 #  include <bionic_atomic_gcc_builtin.h>
 #endif
diff --git a/libc/private/bionic_atomic_mips.h b/libc/private/bionic_atomic_mips.h
new file mode 100644
index 0000000..28fe88d
--- /dev/null
+++ b/libc/private/bionic_atomic_mips.h
@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef BIONIC_ATOMIC_MIPS_H
+#define BIONIC_ATOMIC_MIPS_H
+
+/* Define a full memory barrier, this is only needed if we build the
+ * platform for a multi-core device.
+ */
+#if defined(ANDROID_SMP) && ANDROID_SMP == 1
+__ATOMIC_INLINE__ void
+__bionic_memory_barrier()
+{
+    __asm__ __volatile__ ( "sync" : : : "memory" );
+}
+#else
+__ATOMIC_INLINE__ void
+__bionic_memory_barrier()
+{
+    /* A simple compiler barrier */
+    __asm__ __volatile__ ( "" : : : "memory" );
+}
+#endif
+
+/* Compare-and-swap, without any explicit barriers. Note that this function
+ * returns 0 on success, and 1 on failure. The opposite convention is typically
+ * used on other platforms.
+ */
+__ATOMIC_INLINE__ int
+__bionic_cmpxchg(int32_t old_value, int32_t new_value, volatile int32_t* ptr)
+{
+    int32_t prev, status;
+    __asm__ __volatile__ ("1: move %[status], %[new_value]  \n"
+                          "   ll %[prev], 0(%[ptr])         \n"
+                          "   bne %[old_value], %[prev], 2f \n"
+                          "   sc   %[status], 0(%[ptr])     \n"
+                          "   beqz %[status], 1b            \n"
+                          "2:                               \n"
+                          : [prev]"=&r"(prev), [status]"=&r"(status), "+m"(*ptr)
+                          : [new_value]"r"(new_value), [old_value]"r"(old_value), [ptr]"r"(ptr)
+                          : "memory");
+    return prev != old_value;
+}
+
+
+/* Swap, without any explicit barriers */
+__ATOMIC_INLINE__ int32_t
+__bionic_swap(int32_t new_value, volatile int32_t *ptr)
+{
+   int32_t prev, status;
+    __asm__ __volatile__ ("1:  move %[status], %[new_value] \n"
+                          "    ll %[prev], 0(%[ptr])        \n"
+                          "    sc %[status], 0(%[ptr])      \n"
+                          "    beqz %[status], 1b           \n"
+                          : [prev]"=&r"(prev), [status]"=&r"(status), "+m"(*ptr)
+                          : [ptr]"r"(ptr), [new_value]"r"(new_value)
+                          : "memory");
+    return prev;
+}
+
+/* Atomic increment, without explicit barriers */
+__ATOMIC_INLINE__ int32_t
+__bionic_atomic_inc(volatile int32_t *ptr)
+{
+    int32_t prev, status;
+    __asm__ __volatile__ ("1:  ll %[prev], 0(%[ptr])        \n"
+                          "    addiu %[status], %[prev], 1  \n"
+                          "    sc   %[status], 0(%[ptr])    \n"
+                          "    beqz %[status], 1b           \n"
+                          : [prev]"=&r" (prev), [status]"=&r"(status), "+m" (*ptr)
+                          : [ptr]"r"(ptr)
+                          : "memory");
+    return prev;
+}
+
+/* Atomic decrement, without explicit barriers */
+__ATOMIC_INLINE__ int32_t
+__bionic_atomic_dec(volatile int32_t *ptr)
+{
+    int32_t prev, status;
+    __asm__ __volatile__ ("1:  ll %[prev], 0(%[ptr])        \n"
+                          "    addiu %[status], %[prev], -1 \n"
+                          "    sc   %[status], 0(%[ptr])    \n"
+                          "    beqz %[status], 1b           \n"
+                          : [prev]"=&r" (prev), [status]"=&r"(status), "+m" (*ptr)
+                          : [ptr]"r"(ptr)
+                          : "memory");
+    return prev;
+}
+#endif /* BIONIC_ATOMIC_MIPS_H */