1 files changed, 62 insertions, 0 deletions
diff --git a/lib/thread.cc b/lib/thread.cc
new file mode 100644
index 0000000..ad07d96
--- /dev/null
+++ b/lib/thread.cc
@@ -0,0 +1,62 @@
+/* Copyright (c) 2020 Johannes Stoelp */
+
+#include "thread.h"
+
+#include "arch/x86_64/asm.h"
+#include "executor.h"
+
+#include <cassert>
+#include <cstdint>     // uintN_t
+#include <sys/mman.h>  // mmap
+#include <unistd.h>    // sysconf
+
+namespace {
+    static long get_pagesize() { return sysconf(_SC_PAGESIZE); }
+}  // namespace
+
+namespace nMatcha {
+    Thread::Thread() {
+        const long PAGE_SIZE = get_pagesize();
+        const long STACK_SIZE = 8 * PAGE_SIZE;
+
+        // create new stack
+        void* stack = mmap(nullptr, STACK_SIZE, PROT_WRITE | PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS, -1 /* fd */, 0 /* offset */);
+        assert(stack != MAP_FAILED);
+
+        // protect last stack page (lowest addr)
+        int ret = mprotect(stack, PAGE_SIZE, PROT_NONE);
+        assert(ret == 0);
+
+        // stack grows downwards
+        mStackPtr = static_cast<uint8_t*>(stack) + STACK_SIZE;
+        {
+            uint64_t* stack = static_cast<uint64_t*>(mStackPtr);
+            *(--stack) = (uint64_t)this;
+            *(--stack) = (uint64_t)Thread::entry;
+
+            // initial values for yield epilog
+            *(--stack) = (uint64_t)thread_create;
+            *(--stack) = (uint64_t)0;
+
+            // initial values for callee saved regs
+            *(--stack) = (uint64_t)0;                                        // rbx
+            *(--stack) = (uint64_t)(static_cast<uint64_t*>(mStackPtr) - 4);  // rbp
+            *(--stack) = (uint64_t)0;                                        // r12
+            *(--stack) = (uint64_t)0;                                        // r13
+            *(--stack) = (uint64_t)0;                                        // r14
+            *(--stack) = (uint64_t)0;                                        // r15
+
+            mStackPtr = static_cast<void*>(stack);
+        }
+    }
+
+    void Thread::entry(void* obj) {
+        Thread* t = static_cast<Thread*>(obj);
+        t->threadFn();
+    }
+
+    void Thread::yield() {
+        assert(mExecutor);
+        ::yield(mExecutor->getStackPtr(), &mStackPtr);
+    }
+}  // namespace nMatcha