summaryrefslogtreecommitdiff
path: root/nuttx/arch/avr/src/avr32/up_initialstate.c
blob: 38fe40d677dced567b0bb27ed75ced5b1a67e945 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
/****************************************************************************
 * arch/avr/src/avr32/up_initialstate.c
 *
 *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <sys/types.h>
#include <stdint.h>
#include <string.h>

#include <nuttx/arch.h>

#include "up_internal.h"
#include "up_arch.h"

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/****************************************************************************
 * Private Data
 ****************************************************************************/

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: up_initial_state
 *
 * Description:
 *   A new thread is being started and a new TCB has been created. This
 *   function is called to initialize the processor specific portions of the
 *   new TCB.
 *
 *   This function must setup the intial architecture registers and/or stack
 *   so that execution will begin at tcb->start  on the next context switch.
 *
 ****************************************************************************/

void up_initial_state(_TCB *tcb)
{
  struct xcptcontext *xcp = &tcb->xcp;

  /* Initialize the initial exception register context structure.  Zeroing
   * all registers is a good debug helper, but should not be necessary.
   */

#ifdef CONFIG_DEBUG
  memset(xcp, 0, sizeof(struct xcptcontext));
#else
  /* No pending signal delivery */

  xcp->sigdeliver   = NULL;
  
  /* Clear the frame pointer and link register since this is the outermost
   * frame.
   */

  xcp->regs[REG_R7] = 0;
  xcp->regs[REG_LR] = 0;
#endif

  /* Set the initial stack pointer to the "base" of the allocated stack */

  xcp->regs[REG_SP]      = (uint32_t)tcb->adj_stack_ptr;

  /* Save the task entry point */

  xcp->regs[REG_PC]      = (uint32_t)tcb->start;

  /* Set supervisor- or user-mode, depending on how NuttX is configured and
   * what kind of thread is being started.  Disable FIQs in any event
   *
   * If the kernel build is not selected, then all threads run in
   * supervisor-mode.
   */

#ifdef CONFIG_NUTTX_KERNEL
#  error "Missing logic for the CONFIG_NUTTX_KERNEL build"
#endif

  /* Enable or disable interrupts, based on user configuration */

#ifdef CONFIG_SUPPRESS_INTERRUPTS
  xcp->regs[REG_SR]    = avr32_sr() | AVR32_SR_GM_MASK;
#else
  xcp->regs[REG_SR]    = avr32_sr() & ~AVR32_SR_GM_MASK;
#endif
}