1 #include <string.h>
2 #include <stdlib.h>
3 #include <com32.h>
4 #include "core.h"
5 #include "thread.h"
6 
7 #define REAL_MODE_STACK_SIZE	4096
8 #define MIN_STACK_SIZE		16384
9 #define THREAD_ALIGN		64 	/* Thread alignment */
10 
11 extern void __start_thread(void);
12 
13 struct thread *start_thread(const char *name, size_t stack_size, int prio,
14 			    void (*start_func)(void *), void *func_arg)
15 {
16     irq_state_t irq;
17     struct thread *curr, *t;
18     char *stack, *rmstack;
19     const size_t thread_mask = THREAD_ALIGN - 1;
20     struct thread_stack *sp;
21 
22     if (stack_size < MIN_STACK_SIZE)
23 	stack_size = MIN_STACK_SIZE;
24 
25     stack_size = (stack_size + thread_mask) & ~thread_mask;
26     stack = malloc(stack_size + sizeof(struct thread));
27     if (!stack)
28 	return NULL;
29     rmstack = lmalloc(REAL_MODE_STACK_SIZE);
30     if (!rmstack) {
31 	free(stack);
32 	return NULL;
33     }
34 
35     t = (struct thread *)stack;
36     memset(t, 0, sizeof *t);
37     t->stack   = stack;
38     t->rmstack = rmstack;
39     stack += sizeof(struct thread);
40 
41     /* sp allocated from the end of the stack */
42     sp = (struct thread_stack *)(stack + stack_size) - 1;
43     t->esp = sp;
44 
45     sp->errno = 0;
46     sp->rmss = SEG(rmstack);
47     sp->rmsp = REAL_MODE_STACK_SIZE;
48     sp->esi = (size_t)start_func;
49     sp->edi = (size_t)func_arg;
50     sp->ebx = irq_state();	/* Inherit the IRQ state from the spawner */
51     sp->eip = __start_thread;
52     t->prio = prio;
53     t->name = name;
54 
55     irq = irq_save();
56     curr = current();
57 
58     t->thread_magic    = THREAD_MAGIC;
59 
60     t->list.prev       = &curr->list;
61     t->list.next       = curr->list.next;
62     curr->list.next    = &t->list;
63     t->list.next->prev = &t->list;
64 
65     __schedule();
66 
67     irq_restore(irq);
68     return t;
69 }
70