Ruby  3.1.4p223 (2023-03-30 revision HEAD)
Context.h
1 #ifndef COROUTINE_WIN64_CONTEXT_H
2 #define COROUTINE_WIN64_CONTEXT_H 1
3 
4 /*
5  * This file is part of the "Coroutine" project and released under the MIT License.
6  *
7  * Created by Samuel Williams on 10/5/2018.
8  * Copyright, 2018, by Samuel Williams.
9 */
10 
11 #pragma once
12 
13 #include <assert.h>
14 #include <stddef.h>
15 #include <stdint.h>
16 #include <string.h>
17 
18 #define COROUTINE __declspec(noreturn) void
19 
20 enum {
21  COROUTINE_REGISTERS = 8,
22  COROUTINE_XMM_REGISTERS = 1+10*2,
23 };
24 
25 struct coroutine_context
26 {
27  void **stack_pointer;
28  void *argument;
29 };
30 
31 typedef void(* coroutine_start)(struct coroutine_context *from, struct coroutine_context *self);
32 
33 void coroutine_trampoline();
34 
35 static inline void coroutine_initialize_main(struct coroutine_context * context) {
36  context->stack_pointer = NULL;
37 }
38 
39 static inline void coroutine_initialize(
40  struct coroutine_context *context,
41  coroutine_start start,
42  void *stack,
43  size_t size
44 ) {
45  assert(start && stack && size >= 1024);
46 
47  // Stack grows down. Force 16-byte alignment.
48  char * top = (char*)stack + size;
49  context->stack_pointer = (void**)((uintptr_t)top & ~0xF);
50 
51  /* Win64 ABI requires space for arguments */
52  context->stack_pointer -= 4;
53 
54  /* Return address */
55  *--context->stack_pointer = 0;
56  *--context->stack_pointer = (void*)start;
57  *--context->stack_pointer = (void*)coroutine_trampoline;
58 
59  /* Windows Thread Information Block */
60  /* *--context->stack_pointer = 0; */ /* gs:[0x00] is not used */
61  *--context->stack_pointer = (void*)top; /* gs:[0x08] */
62  *--context->stack_pointer = (void*)stack; /* gs:[0x10] */
63 
64  context->stack_pointer -= COROUTINE_REGISTERS;
65  memset(context->stack_pointer, 0, sizeof(void*) * COROUTINE_REGISTERS);
66  memset(context->stack_pointer - COROUTINE_XMM_REGISTERS, 0, sizeof(void*) * COROUTINE_XMM_REGISTERS);
67 }
68 
69 struct coroutine_context * coroutine_transfer(struct coroutine_context * current, struct coroutine_context * target);
70 
71 static inline void coroutine_destroy(struct coroutine_context * context)
72 {
73 }
74 
75 #endif /* COROUTINE_WIN64_CONTEXT_H */