start_thread.c revision 76d05dc695b06c4e987bb8078f78032441e1430c 
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
11extern void __start_thread(void);
12
13struct 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