Native implementation of coroutines to improve performance of fibers

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65834 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

coroutine/win32/Context.asm

@@ -0,0 +1,43 @@
+;;
+;;  win32.asm
+;;  File file is part of the "Coroutine" project and released under the MIT License.
+;;
+;;  Created by Samuel Williams on 10/5/2018.
+;;  Copyright, 2018, by Samuel Williams. All rights reserved.
+;;
+
+.model flat
+
+.code
+
+; Using fastcall is a big win (and it's the same has how x64 works).
+; In coroutine transfer, the arguments are passed in ecx and edx. We don't need
+; to touch these in order to pass them to the destination coroutine.
+
+@coroutine_transfer@8 proc
+	; Save caller registers
+	push ebp
+	push ebx
+	push edi
+	push esi
+	
+	; Save caller stack pointer
+	mov dword ptr [ecx], esp
+	
+	; Restore callee stack pointer
+	mov esp, dword ptr [edx]
+
+	; Restore callee stack
+	pop esi
+	pop edi
+	pop ebx
+	pop ebp
+
+	; Save the first argument as the return value
+	mov eax, dword ptr ecx
+
+	; Jump to the address on the stack
+	ret
+@coroutine_transfer@8 endp
+
+end

coroutine/win32/Context.h

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+//
+//  win32.h
+//  File file is part of the "Coroutine" project and released under the MIT License.
+//
+//  Created by Samuel Williams on 10/5/2018.
+//  Copyright, 2018, by Samuel Williams. All rights reserved.
+//
+
+#pragma once
+
+#include <assert.h>
+#include <string.h>
+
+#if __cplusplus
+extern "C" {
+#endif
+
+#define COROUTINE void __fastcall
+
+const size_t COROUTINE_REGISTERS = 4;
+
+// The fiber context (stack pointer).
+struct coroutine_context
+{
+	void **stack_pointer;
+};
+
+// The initialization function.
+typedef void(__fastcall * coroutine_start)(coroutine_context *from, coroutine_context *self);
+
+inline void coroutine_initialize(
+	coroutine_context *context,
+	coroutine_start start,
+	void *stack_pointer,
+	size_t stack_size
+) {
+	context->stack_pointer = (void**)stack_pointer;
+
+	if (!start) {
+		assert(!context->stack_pointer);
+		/* We are main coroutine for this thread */
+		return;
+	}
+
+	/* Windows Thread Information Block */
+	*--context->stack_pointer = 0;
+	*--context->stack_pointer = stack_pointer;
+	*--context->stack_pointer = (void*)stack_size;
+
+	*--context->stack_pointer = (void*)start;
+
+	context->stack_pointer -= COROUTINE_REGISTERS;
+	memset(context->stack_pointer, 0, sizeof(void*) * COROUTINE_REGISTERS);
+}
+
+coroutine_context * __fastcall coroutine_transfer(coroutine_context * current, coroutine_context * target);
+
+inline void coroutine_destroy(coroutine_context * context)
+{
+}
+
+#if __cplusplus
+}
+#endif