stm32f4 __wfi

Jython googcheng at gmail.com
Wed Apr 24 08:44:21 UTC 2019


i searched it by add -i

56794:0000d040 <_CPU_Thread_Idle_body>:
56795-#ifdef ARM_MULTILIB_HAS_WFI
56796-
56797:void *_CPU_Thread_Idle_body( uintptr_t ignored )
56798-{
56799-  while ( true ) {
56800-    __asm__ volatile ("wfi");
56801-    d040:    bf30          wfi
56802-  }
56803:    d042:    e7fd          b.n    d040 <_CPU_Thread_Idle_body>
56804-
56805-0000d044 <rtems_filesystem_default_close>:
56806-int rtems_filesystem_default_close(
56807-  rtems_libio_t *iop
56808-)
56809-{
56810-  return 0;
56811-}
56812-    d044:    2000          movs    r0, #0
56813-    d046:    4770          bx    lr


that's to say when i want to enter low power  i just need to call sleep or
rtems_task_wake_after or just while(1); ?

On Wed, Apr 24, 2019 at 4:36 PM Christian Mauderer <
christian.mauderer at embedded-brains.de> wrote:

> For some reason your grep hasn't found the _CPU_Thread_Idle_body. It's
> possible that the stm32f4 uses some other function for that also I don't
> know why.
>
> For example for the xilinx_zynq_a9_qemu BSP the disassembled idle body
> looks like follows:
>
> void *_CPU_Thread_Idle_body( uintptr_t ignored )
> {
>    11d70:       b480            push    {r7}
>    11d72:       b083            sub     sp, #12
>    11d74:       af00            add     r7, sp, #0
>    11d76:       6078            str     r0, [r7, #4]
>   while ( true ) {
> #ifdef ARM_MULTILIB_HAS_WFI
>     __asm__ volatile ("wfi");
>    11d78:       bf30            wfi
>    11d7a:       e7fd            b.n     11d78 <_CPU_Thread_Idle_body+0x8>
>
> Am 24.04.19 um 10:25 schrieb Jython:
> > arm-rtems4.11-objdump -dS hello.exe | grep idle --color=auto -n -B 5 -A
> 12
> >
> > there is no idle function which calls wfi command
> > // log
> > 508-
> > 509-
> > 510-
> > 511-    }
> > 512-
> > 513:    if((*USART2_SR) & (1<<4))  // idle
> > 514-     3aa:    4b13          ldr    r3, [pc, #76]    ; (3f8
> > <USART2_handler+0x94>)
> > 515-     3ac:    681b          ldr    r3, [r3, #0]
> > 516-     3ae:    681b          ldr    r3, [r3, #0]
> > 517-     3b0:    f003 0310     and.w    r3, r3, #16
> > 518-     3b4:    2b00          cmp    r3, #0
> > 519-     3b6:    d00a          beq.n    3ce <USART2_handler+0x6a>
> > 520-    {
> > 521:        //printk("idle ");
> > 522-
> > 523-        temp = (*USART2_SR);
> > 524-     3b8:    4b0f          ldr    r3, [pc, #60]    ; (3f8
> > <USART2_handler+0x94>)
> > 525-     3ba:    681b          ldr    r3, [r3, #0]
> > 526-     3bc:    681b          ldr    r3, [r3, #0]
> > 527-     3be:    60fb          str    r3, [r7, #12]
> > 528-        temp = (*USART2_DR);
> > 529-     3c0:    4b0f          ldr    r3, [pc, #60]    ; (400
> > <USART2_handler+0x9c>)
> > 530-     3c2:    681b          ldr    r3, [r3, #0]
> > 531-     3c4:    681b          ldr    r3, [r3, #0]
> > 532-     3c6:    60fb          str    r3, [r7, #12]
> > 533-        //temp = temp;
> > --
> > 627-
> > 628-
> > 629-
> > 630-    }
> > 631-
> > 632:    if((*USART3_SR) & (1<<4))  // idle
> > 633-     44c:    4b12          ldr    r3, [pc, #72]    ; (498
> > <USART3_handler+0x8c>)
> > 634-     44e:    681b          ldr    r3, [r3, #0]
> > 635-     450:    681b          ldr    r3, [r3, #0]
> > 636-     452:    f003 0310     and.w    r3, r3, #16
> > 637-     456:    2b00          cmp    r3, #0
> > 638-     458:    d00a          beq.n    470 <USART3_handler+0x64>
> > 639-    {
> > 640:        //printk("idle ");
> > 641-
> > 642-        temp = (*USART3_SR);
> > 643-     45a:    4b0f          ldr    r3, [pc, #60]    ; (498
> > <USART3_handler+0x8c>)
> > 644-     45c:    681b          ldr    r3, [r3, #0]
> > 645-     45e:    681b          ldr    r3, [r3, #0]
> > 646-     460:    60fb          str    r3, [r7, #12]
> > 647-        temp = (*USART3_DR);
> > 648-     462:    4b0f          ldr    r3, [pc, #60]    ; (4a0
> > <USART3_handler+0x94>)
> > 649-     464:    681b          ldr    r3, [r3, #0]
> > 650-     466:    681b          ldr    r3, [r3, #0]
> > 651-     468:    60fb          str    r3, [r7, #12]
> > 652-
> > --
> > 26329-
> > 26330-    if (newTail == tty->rawOutBuf.Head) {
> > 26331-      /*
> > 26332-       * Buffer has become empty
> > 26333-       */
> > 26334:      tty->rawOutBufState = rob_idle;
> > 26335-    69a0:    f880 5094     strb.w    r5, [r0, #148]    ; 0x94
> > 26336-      (*tty->handler.write) (ctx, NULL, 0);
> > 26337-    69a4:    f8d4 30c4     ldr.w    r3, [r4, #196]    ; 0xc4
> > 26338-    69a8:    4670          mov    r0, lr
> > 26339-    69aa:    4629          mov    r1, r5
> > 26340-    69ac:    462a          mov    r2, r5
> > 26341-    69ae:    4798          blx    r3
> > 26342-      nToSend = 0;
> > 26343-
> > 26344-      /*
> > 26345-       * check to see if snd wakeup callback was set
> > 26346-       */
> > --
> > 26443-    6a12:    2600          movs    r6, #0
> > 26444-    6a14:    e7ac          b.n    6970
> > <rtems_termios_refill_transmitter+0x7c>
> > 26445-      /*
> > 26446-       * Buffer has become empty
> > 26447-       */
> > 26448:      tty->rawOutBufState = rob_idle;
> > 26449-      (*tty->handler.write) (ctx, NULL, 0);
> > 26450-      nToSend = 0;
> > 26451-    6a16:    461d          mov    r5, r3
> > 26452-    6a18:    e7aa          b.n    6970
> > <rtems_termios_refill_transmitter+0x7c>
> > 26453-    6a1a:    bf00          nop
> > 26454-
> > 26455-00006a1c <rtems_termios_txdaemon>:
> > 26456-
> > 26457-/*
> > 26458- * this task actually processes any transmit events
> > 26459- */
> > 26460-static rtems_task rtems_termios_txdaemon(rtems_task_argument
> argument)
> > --
> > 27083-      RTEMS_NO_PRIORITY,
> > 27084-      &tty->rawOutBuf.Semaphore);
> > 27085-    if (sc != RTEMS_SUCCESSFUL)
> > 27086-    6cc0:    2800          cmp    r0, #0
> > 27087-    6cc2:    f040 80d6     bne.w    6e72
> > <rtems_termios_open_tty+0x2de>
> > 27088:    tty->rawOutBufState = rob_idle;
> > 27089-
> > 27090-    /*
> > 27091-     * Set callbacks
> > 27092-     */
> > 27093-    if (device_node != NULL) {
> > 27094-    6cc6:    9b0e          ldr    r3, [sp, #56]    ; 0x38
> > 27095-      RTEMS_SIMPLE_BINARY_SEMAPHORE | RTEMS_FIFO,
> > 27096-      RTEMS_NO_PRIORITY,
> > 27097-      &tty->rawOutBuf.Semaphore);
> > 27098-    if (sc != RTEMS_SUCCESSFUL)
> > 27099-      rtems_fatal_error_occurred (sc);
> > 27100:    tty->rawOutBufState = rob_idle;
> > 27101-    6cc8:    f884 0094     strb.w    r0, [r4, #148]    ; 0x94
> > 27102-
> > 27103-    /*
> > 27104-     * Set callbacks
> > 27105-     */
> > 27106-    if (device_node != NULL) {
> > 27107-    6ccc:    2b00          cmp    r3, #0
> > 27108-    6cce:    f000 80e9     beq.w    6ea4
> > <rtems_termios_open_tty+0x310>
> > 27109-      device_node->tty = tty;
> > 27110-      tty->handler = *device_node->handler;
> > 27111-    6cd2:    f104 0cb8     add.w    ip, r4, #184    ; 0xb8
> > 27112-    6cd6:    4666          mov    r6, ip
> > --
> > 29226-      /* disable interrupts    */
> > 29227-      rtems_termios_device_lock_acquire (ctx, &lock_context);
> > 29228-      tty->flow_ctrl &= ~FL_OSTOP;
> > 29229-    7442:    f8d4 30d8     ldr.w    r3, [r4, #216]    ; 0xd8
> > 29230-      /* check for chars in output buffer (or rob_state?) */
> > 29231:      if (tty->rawOutBufState != rob_idle) {
> > 29232-    7446:    f894 2094     ldrb.w    r2, [r4, #148]    ; 0x94
> > 29233-
> > 29234-    /* has output been stopped due to received XOFF? */
> > 29235-    if (tty->flow_ctrl & FL_OSTOP) {
> > 29236-      /* disable interrupts    */
> > 29237-      rtems_termios_device_lock_acquire (ctx, &lock_context);
> > 29238-      tty->flow_ctrl &= ~FL_OSTOP;
> > 29239-    744a:    f023 0320     bic.w    r3, r3, #32
> > 29240-    744e:    f8c4 30d8     str.w    r3, [r4, #216]    ; 0xd8
> > 29241-      /* check for chars in output buffer (or rob_state?) */
> > 29242:      if (tty->rawOutBufState != rob_idle) {
> > 29243-    7452:    2a00          cmp    r2, #0
> > 29244-    7454:    f040 80cf     bne.w    75f6
> <rtems_termios_ioctl+0x306>
> > 29245-    ARM_SWITCH_BACK
> > 29246-    : ARM_SWITCH_OUTPUT
> > 29247-    : [level] "r" (level)
> > 29248-  );
> > 29249-#elif defined(ARM_MULTILIB_ARCH_V7M)
> > 29250-  __asm__ volatile (
> > 29251-    7458:    f387 8811     msr    BASEPRI, r7
> > 29252-      /* reenable interrupts */
> > 29253-      rtems_termios_device_lock_release (ctx, &lock_context);
> > 29254-    }
> > --
> > 29492-
> > 29493-  rtems_termios_device_lock_acquire (ctx, &lock_context);
> > 29494-  tty->rawOutBuf.Tail = 0;
> > 29495-    7572:    f8c4 0084     str.w    r0, [r4, #132]    ; 0x84
> > 29496-  tty->rawOutBuf.Head = 0;
> > 29497:  tty->rawOutBufState = rob_idle;
> > 29498-    7576:    f884 0094     strb.w    r0, [r4, #148]    ; 0x94
> > 29499-  rtems_termios_device_context *ctx = tty->device_context;
> > 29500-  rtems_interrupt_lock_context lock_context;
> > 29501-
> > 29502-  rtems_termios_device_lock_acquire (ctx, &lock_context);
> > 29503-  tty->rawOutBuf.Tail = 0;
> > 29504-  tty->rawOutBuf.Head = 0;
> > 29505-    757a:    f8c4 0080     str.w    r0, [r4, #128]    ; 0x80
> > 29506-    ARM_SWITCH_BACK
> > 29507-    : ARM_SWITCH_OUTPUT
> > 29508-    : [level] "r" (level)
> > 29509-  );
> > --
> > 29562-
> > 29563-  rtems_termios_device_lock_acquire (ctx, &lock_context);
> > 29564-  tty->rawOutBuf.Tail = 0;
> > 29565-    75b0:    f8c4 0084     str.w    r0, [r4, #132]    ; 0x84
> > 29566-  tty->rawOutBuf.Head = 0;
> > 29567:  tty->rawOutBufState = rob_idle;
> > 29568-    75b4:    f884 0094     strb.w    r0, [r4, #148]    ; 0x94
> > 29569-  rtems_termios_device_context *ctx = tty->device_context;
> > 29570-  rtems_interrupt_lock_context lock_context;
> > 29571-
> > 29572-  rtems_termios_device_lock_acquire (ctx, &lock_context);
> > 29573-  tty->rawOutBuf.Tail = 0;
> > 29574-  tty->rawOutBuf.Head = 0;
> > 29575-    75b8:    f8c4 0080     str.w    r0, [r4, #128]    ; 0x80
> > 29576-    ARM_SWITCH_BACK
> > 29577-    : ARM_SWITCH_OUTPUT
> > 29578-    : [level] "r" (level)
> > 29579-  );
> > --
> > 29629-    75f0:    2301          movs    r3, #1
> > 29630-    75f2:    66e3          str    r3, [r4, #108]    ; 0x6c
> > 29631-    75f4:    e77e          b.n    74f4 <rtems_termios_ioctl+0x204>
> > 29632-      tty->flow_ctrl &= ~FL_OSTOP;
> > 29633-      /* check for chars in output buffer (or rob_state?) */
> > 29634:      if (tty->rawOutBufState != rob_idle) {
> > 29635-        /* if chars available, call write function... */
> > 29636-        (*tty->handler.write)(
> > 29637-          ctx, &tty->rawOutBuf.theBuf[tty->rawOutBuf.Tail],1);
> > 29638-    75f6:    f8d4 2084     ldr.w    r2, [r4, #132]    ; 0x84
> > 29639-      rtems_termios_device_lock_acquire (ctx, &lock_context);
> > 29640-      tty->flow_ctrl &= ~FL_OSTOP;
> > 29641-      /* check for chars in output buffer (or rob_state?) */
> > 29642:      if (tty->rawOutBufState != rob_idle) {
> > 29643-        /* if chars available, call write function... */
> > 29644-        (*tty->handler.write)(
> > 29645-    75fa:    6fe1          ldr    r1, [r4, #124]    ; 0x7c
> > 29646-    75fc:    f8d4 30c4     ldr.w    r3, [r4, #196]    ; 0xc4
> > 29647-    7600:    4411          add    r1, r2
> > 29648-    7602:    4628          mov    r0, r5
> > 29649-    7604:    2201          movs    r2, #1
> > 29650-    7606:    4798          blx    r3
> > 29651-    7608:    e726          b.n    7458 <rtems_termios_ioctl+0x168>
> > 29652-    760a:    bf00          nop
> > 29653-
> > 29654-0000760c <rtems_termios_puts>:
> > --
> > 29815-    76b2:    bf24          itt    cs
> > 29816-    76b4:    f8d4 2088     ldrcs.w    r2, [r4, #136]    ; 0x88
> > 29817-    76b8:    1a9b          subcs    r3, r3, r2
> > 29818-    tty->rawOutBuf.Head = newHead;
> > 29819-
> > 29820:    if (tty->rawOutBufState == rob_idle) {
> > 29821-    76ba:    f894 2094     ldrb.w    r2, [r4, #148]    ; 0x94
> > 29822-    memcpy(&tty->rawOutBuf.theBuf[tty->rawOutBuf.Head], buf,
> nToCopy);
> > 29823-
> > 29824-    newHead = tty->rawOutBuf.Head + nToCopy;
> > 29825-    if (newHead >= tty->rawOutBuf.Size)
> > 29826-      newHead -= tty->rawOutBuf.Size;
> > 29827-    tty->rawOutBuf.Head = newHead;
> > 29828-    76be:    f8c4 3080     str.w    r3, [r4, #128]    ; 0x80
> > 29829-
> > 29830:    if (tty->rawOutBufState == rob_idle) {
> > 29831-    76c2:    b192          cbz    r2, 76ea
> <rtems_termios_puts+0xde>
> > 29832-    ARM_SWITCH_BACK
> > 29833-    : ARM_SWITCH_OUTPUT
> > 29834-    : [level] "r" (level)
> > 29835-  );
> > 29836-#elif defined(ARM_MULTILIB_ARCH_V7M)
> > 29837-  __asm__ volatile (
> > 29838-    76c4:    f385 8811     msr    BASEPRI, r5
> > 29839-  if (tty->handler.mode == TERMIOS_POLLED) {
> > 29840-    (*tty->handler.write)(ctx, buf, len);
> > 29841-    return;
> > 29842-  }
> > --
> > 29885-    76e8:    e7d2          b.n    7690 <rtems_termios_puts+0x84>
> > 29886-    if (newHead >= tty->rawOutBuf.Size)
> > 29887-      newHead -= tty->rawOutBuf.Size;
> > 29888-    tty->rawOutBuf.Head = newHead;
> > 29889-
> > 29890:    if (tty->rawOutBufState == rob_idle) {
> > 29891-      startXmit (tty, tty->rawOutBuf.Tail, false);
> > 29892-    76ea:    f8d4 1084     ldr.w    r1, [r4, #132]    ; 0x84
> > 29893-    76ee:    4620          mov    r0, r4
> > 29894-    76f0:    f7ff f8ca     bl    6888 <startXmit>
> > 29895-    76f4:    e7e6          b.n    76c4 <rtems_termios_puts+0xb8>
> > 29896-  rtems_termios_device_context *ctx = tty->device_context;
> > 29897-  rtems_interrupt_lock_context lock_context;
> > 29898-  rtems_status_code sc;
> > 29899-
> > 29900-  if (tty->handler.mode == TERMIOS_POLLED) {
> > 29901-    (*tty->handler.write)(ctx, buf, len);
> > 29902-    76f6:    f8d2 30c4     ldr.w    r3, [r2, #196]    ; 0xc4
> > --
> > 31283-    while ((tty->rawInBuf.Head != tty->rawInBuf.Tail) &&
> > 31284-    7be4:    428a          cmp    r2, r1
> > 31285-    7be6:    f04f 0501     mov.w    r5, #1
> > 31286-    7bea:    d968          bls.n    7cbe <rtems_termios_read+0x1a6>
> > 31287-             ==                (FL_MDXON | FL_ISNTXOF))
> > 31288:            && ((tty->rawOutBufState == rob_idle)
> > 31289-          || (tty->flow_ctrl & FL_OSTOP))) {
> > 31290-          /* XON should be sent now... */
> > 31291-          (*tty->handler.write)(
> > 31292-            tty->device_context, (void
> > *)&(tty->termios.c_cc[VSTART]), 1);
> > 31293-    7bec:    f104 0849     add.w    r8, r4, #73    ; 0x49
> > 31294-    7bf0:    e012          b.n    7c18 <rtems_termios_read+0x100>
> > 31295-
> > 31296-      rtems_termios_device_lock_release (ctx, &lock_context);
> > 31297-
> > 31298-      /* continue processing new character */
> > 31299-      if (tty->termios.c_lflag & ICANON) {
> > 31300-        if (siproc (c, tty))
> > --
> > 31401-        if (((tty->flow_ctrl & (FL_MDXON | FL_ISNTXOF))
> > 31402-    7c56:    f8d4 20d8     ldr.w    r2, [r4, #216]    ; 0xd8
> > 31403-    7c5a:    4013          ands    r3, r2
> > 31404-    7c5c:    4553          cmp    r3, sl
> > 31405-    7c5e:    d01e          beq.n    7c9e <rtems_termios_read+0x186>
> > 31406:            && ((tty->rawOutBufState == rob_idle)
> > 31407-          || (tty->flow_ctrl & FL_OSTOP))) {
> > 31408-          /* XON should be sent now... */
> > 31409-          (*tty->handler.write)(
> > 31410-            tty->device_context, (void
> > *)&(tty->termios.c_cc[VSTART]), 1);
> > 31411-        } else if (tty->flow_ctrl & FL_MDRTS) {
> > 31412-    7c60:    f8d4 30d8     ldr.w    r3, [r4, #216]    ; 0xd8
> > 31413-    7c64:    05da          lsls    r2, r3, #23
> > 31414-    7c66:    d50b          bpl.n    7c80 <rtems_termios_read+0x168>
> > 31415-          tty->flow_ctrl &= ~FL_IRTSOFF;
> > 31416-    7c68:    f8d4 30d8     ldr.w    r3, [r4, #216]    ; 0xd8
> > 31417-          /* activate RTS line */
> > 31418-          if (tty->flow.start_remote_tx != NULL) {
> > --
> > 31477-         < tty->lowwater) {
> > 31478-        tty->flow_ctrl &= ~FL_IREQXOF;
> > 31479-        /* if tx stopped and XON should be sent... */
> > 31480-        if (((tty->flow_ctrl & (FL_MDXON | FL_ISNTXOF))
> > 31481-             ==                (FL_MDXON | FL_ISNTXOF))
> > 31482:            && ((tty->rawOutBufState == rob_idle)
> > 31483-    7c9e:    f894 3094     ldrb.w    r3, [r4, #148]    ; 0x94
> > 31484-    7ca2:    b11b          cbz    r3, 7cac
> <rtems_termios_read+0x194>
> > 31485-          || (tty->flow_ctrl & FL_OSTOP))) {
> > 31486-    7ca4:    f8d4 30d8     ldr.w    r3, [r4, #216]    ; 0xd8
> > 31487-    7ca8:    0699          lsls    r1, r3, #26
> > 31488-    7caa:    d5d9          bpl.n    7c60 <rtems_termios_read+0x148>
> > 31489-          /* XON should be sent now... */
> > 31490-          (*tty->handler.write)(
> > 31491-    7cac:    f8d4 30c4     ldr.w    r3, [r4, #196]    ; 0xc4
> > 31492-    7cb0:    f8d4 010c     ldr.w    r0, [r4, #268]    ; 0x10c
> > 31493-    7cb4:    4641          mov    r1, r8
> > 31494-    7cb6:    2201          movs    r2, #1
> > --
> > 32101-        /* disable interrupts    */
> > 32102-        rtems_termios_device_lock_acquire (ctx, &lock_context);
> > 32103-        tty->flow_ctrl &= ~FL_OSTOP;
> > 32104-    7f34:    f8d4 30d8     ldr.w    r3, [r4, #216]    ; 0xd8
> > 32105-        /* check for chars in output buffer (or rob_state?) */
> > 32106:        if (tty->rawOutBufState != rob_idle) {
> > 32107-    7f38:    f894 2094     ldrb.w    r2, [r4, #148]    ; 0x94
> > 32108-    if (flow_rcv) {
> > 32109-      /* restart output according to FL_ORCVXOF flag */
> > 32110-      if ((tty->flow_ctrl & (FL_ORCVXOF | FL_OSTOP)) == FL_OSTOP) {
> > 32111-        /* disable interrupts    */
> > 32112-        rtems_termios_device_lock_acquire (ctx, &lock_context);
> > 32113-        tty->flow_ctrl &= ~FL_OSTOP;
> > 32114-    7f3c:    f023 0320     bic.w    r3, r3, #32
> > 32115-    7f40:    f8c4 30d8     str.w    r3, [r4, #216]    ; 0xd8
> > 32116-        /* check for chars in output buffer (or rob_state?) */
> > 32117:        if (tty->rawOutBufState != rob_idle) {
> > 32118-    7f44:    b94a          cbnz    r2, 7f5a
> > <rtems_termios_enqueue_raw_characters+0x1ca>
> > 32119-    ARM_SWITCH_BACK
> > 32120-    : ARM_SWITCH_OUTPUT
> > 32121-    : [level] "r" (level)
> > 32122-  );
> > 32123-#elif defined(ARM_MULTILIB_ARCH_V7M)
> > 32124-  __asm__ volatile (
> > 32125-    7f46:    f386 8811     msr    BASEPRI, r6
> > 32126-    7f4a:    2601          movs    r6, #1
> > 32127-    7f4c:    e760          b.n    7e10
> > <rtems_termios_enqueue_raw_characters+0x80>
> > 32128-        if (( !tty->tty_rcvwakeup ) && ( tty->tty_rcv.sw_pfn !=
> > NULL )) {
> > 32129-          (*tty->tty_rcv.sw_pfn)(&tty->termios,
> tty->tty_rcv.sw_arg);
> > --
> > 32136-    7f52:    9300          str    r3, [sp, #0]
> > 32137-    7f54:    f38a 8811     msr    BASEPRI, sl
> > 32138-    7f58:    e75a          b.n    7e10
> > <rtems_termios_enqueue_raw_characters+0x80>
> > 32139-        tty->flow_ctrl &= ~FL_OSTOP;
> > 32140-        /* check for chars in output buffer (or rob_state?) */
> > 32141:        if (tty->rawOutBufState != rob_idle) {
> > 32142-          /* if chars available, call write function... */
> > 32143-          (*tty->handler.write)(
> > 32144-            ctx, &tty->rawOutBuf.theBuf[tty->rawOutBuf.Tail], 1);
> > 32145-    7f5a:    f8d4 2084     ldr.w    r2, [r4, #132]    ; 0x84
> > 32146-        rtems_termios_device_lock_acquire (ctx, &lock_context);
> > 32147-        tty->flow_ctrl &= ~FL_OSTOP;
> > 32148-        /* check for chars in output buffer (or rob_state?) */
> > 32149:        if (tty->rawOutBufState != rob_idle) {
> > 32150-          /* if chars available, call write function... */
> > 32151-          (*tty->handler.write)(
> > 32152-    7f5e:    6fe1          ldr    r1, [r4, #124]    ; 0x7c
> > 32153-    7f60:    f8d4 30c4     ldr.w    r3, [r4, #196]    ; 0xc4
> > 32154-    7f64:    4411          add    r1, r2
> > 32155-    7f66:    4658          mov    r0, fp
> > 32156-    7f68:    2201          movs    r2, #1
> > 32157-    7f6a:    f8cd c004     str.w    ip, [sp, #4]
> > 32158-    7f6e:    4798          blx    r3
> > 32159-    7f70:    f8dd c004     ldr.w    ip, [sp, #4]
> > 32160-    7f74:    e7e7          b.n    7f46
> > <rtems_termios_enqueue_raw_characters+0x1b6>
> > 32161-          + tty->rawInBuf.Size) % tty->rawInBuf.Size) >
> > tty->highwater)) {
> > --
> > 32167-    7f76:    0692          lsls    r2, r2, #26
> > 32168-    7f78:    d403          bmi.n    7f82
> > <rtems_termios_enqueue_raw_characters+0x1f2>
> > 32169-    7f7a:    f894 2094     ldrb.w    r2, [r4, #148]    ; 0x94
> > 32170-    7f7e:    2a00          cmp    r2, #0
> > 32171-    7f80:    d18c          bne.n    7e9c
> > <rtems_termios_enqueue_raw_characters+0x10c>
> > 32172:              (tty->rawOutBufState == rob_idle)) {
> > 32173-            /* if tx is stopped due to XOFF or out of data */
> > 32174-            /*    call write function here                 */
> > 32175-            tty->flow_ctrl |= FL_ISNTXOF;
> > 32176-    7f82:    f8d4 20d8     ldr.w    r2, [r4, #216]    ; 0xd8
> > 32177-    7f86:    9301          str    r3, [sp, #4]
> > 32178-    7f88:    f042 0202     orr.w    r2, r2, #2
> > 32179-    7f8c:    f8c4 20d8     str.w    r2, [r4, #216]    ; 0xd8
> > 32180-            (*tty->handler.write)(ctx,
> > 32181-    7f90:    f8d4 30c4     ldr.w    r3, [r4, #196]    ; 0xc4
> > 32182-    7f94:    4658          mov    r0, fp
> > 32183-    7f96:    f104 014a     add.w    r1, r4, #74    ; 0x4a
> > 32184-    7f9a:    2201          movs    r2, #1
> > --
> > 38521-    9512:    f000 f825     bl    9560
> > <_Extension_Manager_initialization>
> > 38522-
> > 38523-  _POSIX_API_Initialize();
> > 38524-    9516:    f000 f863     bl    95e0 <_POSIX_API_Initialize>
> > 38525-    951a:    7025          strb    r5, [r4, #0]
> > 38526:  _Thread_Create_idle();
> > 38527-
> > 38528-  /*
> > 38529-   *  Scheduling can properly occur now as long as we avoid
> > dispatching.
> > 38530-   */
> > 38531-}
> > 38532-    951c:    e8bd 4038     ldmia.w    sp!, {r3, r4, r5, lr}
> > 38533-   *  _Thread_Executing and _Thread_Heir are not set.
> > 38534-   *
> > 38535-   *  At this point all API extensions are in place.  After the
> > call to
> > 38536:   *  _Thread_Create_idle() _Thread_Executing and _Thread_Heir
> > will be set.
> > 38537-   */
> > 38538:  _Thread_Create_idle();
> > 38539:    9520:    f002 ba3a     b.w    b998 <_Thread_Create_idle>
> > 38540-    9524:    20004618     .word    0x20004618
> > 38541-    9528:    20004640     .word    0x20004640
> > 38542-    952c:    200041d0     .word    0x200041d0
> > 38543-    9530:    200041e0     .word    0x200041e0
> > 38544-    9534:    2000429c     .word    0x2000429c
> > 38545-    9538:    20004298     .word    0x20004298
> > 38546-
> > 38547-0000953c <rtems_initialize_before_drivers>:
> > 38548-   *  Scheduling can properly occur now as long as we avoid
> > dispatching.
> > 38549-   */
> > 38550-}
> > 38551-
> > --
> > 48137-)
> > 48138-{
> > 48139-    b3c4:    4770          bx    lr
> > 48140-    b3c6:    bf00          nop
> > 48141-
> > 48142:0000b3c8 <_Scheduler_default_Start_idle>:
> > 48143-#if defined(RTEMS_SMP)
> > 48144-  Thread_Control *needs_help;
> > 48145-
> > 48146-  needs_help =
> > 48147-#endif
> > 48148-  ( *scheduler->Operations.unblock )( scheduler, the_thread );
> > 48149:    b3c8:    4801          ldr    r0, [pc, #4]    ; (b3d0
> > <_Scheduler_default_Start_idle+0x8>)
> > 48150-    b3ca:    6943          ldr    r3, [r0, #20]
> > 48151-    b3cc:    4718          bx    r3
> > 48152-    b3ce:    bf00          nop
> > 48153-    b3d0:    0001847c     .word    0x0001847c
> > 48154-
> > 48155-0000b3d4 <_Scheduler_default_Tick>:
> > 48156-  /*
> > 48157-   *  If the thread is not preemptible or is not ready, then
> > 48158-   *  just return.
> > 48159-   */
> > 48160-
> > 48161-  if ( !executing->is_preemptible )
> > --
> > 49735-    b988:    0001847c     .word    0x0001847c
> > 49736-    b98c:    0001d828     .word    0x0001d828
> > 49737-    b990:    0001d814     .word    0x0001d814
> > 49738-    b994:    0001d878     .word    0x0001d878
> > 49739-
> > 49740:0000b998 <_Thread_Create_idle>:
> > 49741-    cpu
> > 49742-  );
> > 49743-}
> > 49744-
> > 49745:void _Thread_Create_idle( void )
> > 49746-{
> > 49747-    b998:    b5f0          push    {r4, r5, r6, r7, lr}
> > 49748-  return maximum_internal_threads;
> > 49749-}
> > 49750-
> > 49751-RTEMS_INLINE_ROUTINE Thread_Control *_Thread_Internal_allocate(
> void )
> > 49752-{
> > 49753-  return (Thread_Control *)
> > 49754:    b99a:    4f17          ldr    r7, [pc, #92]    ; (b9f8
> > <_Thread_Create_idle+0x60>)
> > 49755-    b99c:    b089          sub    sp, #36    ; 0x24
> > 49756-    b99e:    4638          mov    r0, r7
> > 49757-    b9a0:    f7fe ff74     bl    a88c
> <_Objects_Allocate_unprotected>
> > 49758-  _Thread_Initialize(
> > 49759-    &_Thread_Internal_information,
> > 49760:    idle,
> > 49761-    _Scheduler_Get_by_CPU( cpu ),
> > 49762-    NULL,        /* allocate the stack */
> > 49763:    _Stack_Ensure_minimum(
> > rtems_configuration_get_idle_task_stack_size() ),
> > 49764:    b9a4:    4e15          ldr    r6, [pc, #84]    ; (b9fc
> > <_Thread_Create_idle+0x64>)
> > 49765- *
> > 49766- * @return This method returns the minimum stack size;
> > 49767- */
> > 49768-RTEMS_INLINE_ROUTINE uint32_t _Stack_Minimum (void)
> > 49769-{
> > 49770-  return rtems_minimum_stack_size;
> > 49771:    b9a6:    4a16          ldr    r2, [pc, #88]    ; (ba00
> > <_Thread_Create_idle+0x68>)
> > 49772-    b9a8:    6a73          ldr    r3, [r6, #36]    ; 0x24
> > 49773-    b9aa:    6811          ldr    r1, [r2, #0]
> > 49774-    b9ac:    4605          mov    r5, r0
> > 49775-    b9ae:    428b          cmp    r3, r1
> > 49776-    b9b0:    bf38          it    cc
> > 49777-    b9b2:    460b          movcc    r3, r1
> > 49778-   *  fields not explicitly assigned were explicitly zeroed by
> > 49779-   *  _Workspace_Initialization.
> > 49780-   */
> > 49781:  idle = _Thread_Internal_allocate();
> > 49782-
> > 49783-  _Thread_Initialize(
> > 49784:    b9b4:    4a13          ldr    r2, [pc, #76]    ; (ba04
> > <_Thread_Create_idle+0x6c>)
> > 49785:static void _Thread_Create_idle_for_cpu( Per_CPU_Control *cpu )
> > 49786-{
> > 49787-  Objects_Name    name;
> > 49788:  Thread_Control *idle;
> > 49789-
> > 49790-  name.name_u32 = _Objects_Build_name( 'I', 'D', 'L', 'E' );
> > 49791:    b9b6:    f8df e058     ldr.w    lr, [pc, #88]    ; ba10
> > <_Thread_Create_idle+0x78>
> > 49792-   *  fields not explicitly assigned were explicitly zeroed by
> > 49793-   *  _Workspace_Initialization.
> > 49794-   */
> > 49795:  idle = _Thread_Internal_allocate();
> > 49796-
> > 49797-  _Thread_Initialize(
> > 49798-    b9ba:    7811          ldrb    r1, [r2, #0]
> > 49799-    b9bc:    2400          movs    r4, #0
> > 49800-    b9be:    2201          movs    r2, #1
> > 49801-    b9c0:    9300          str    r3, [sp, #0]
> > 49802-    b9c2:    9102          str    r1, [sp, #8]
> > 49803-    b9c4:    f8cd e01c     str.w    lr, [sp, #28]
> > 49804-    b9c8:    4629          mov    r1, r5
> > 49805-    b9ca:    4623          mov    r3, r4
> > 49806-    b9cc:    9203          str    r2, [sp, #12]
> > 49807-    b9ce:    4638          mov    r0, r7
> > 49808-    b9d0:    9401          str    r4, [sp, #4]
> > 49809-    b9d2:    9404          str    r4, [sp, #16]
> > 49810-    b9d4:    9405          str    r4, [sp, #20]
> > 49811-    b9d6:    9406          str    r4, [sp, #24]
> > 49812:    b9d8:    4a0b          ldr    r2, [pc, #44]    ; (ba08
> > <_Thread_Create_idle+0x70>)
> > 49813-    b9da:    f000 f96d     bl    bcb8 <_Thread_Initialize>
> > 49814-   *             MUST be done before _Thread_Start is invoked.
> > 49815-   */
> > 49816-  cpu->heir      =
> > 49817:  cpu->executing = idle;
> > 49818-
> > 49819-  _Thread_Start(
> > 49820-    b9de:    6a32          ldr    r2, [r6, #32]
> > 49821-  /*
> > 49822-   *  WARNING!!! This is necessary to "kick" start the system and
> > 49823-   *             MUST be done before _Thread_Start is invoked.
> > 49824-   */
> > 49825-  cpu->heir      =
> > 49826:  cpu->executing = idle;
> > 49827:    b9e0:    4e0a          ldr    r6, [pc, #40]    ; (ba0c
> > <_Thread_Create_idle+0x74>)
> > 49828-
> > 49829-  _Thread_Start(
> > 49830-    b9e2:    9400          str    r4, [sp, #0]
> > 49831-    b9e4:    9601          str    r6, [sp, #4]
> > 49832-    b9e6:    4628          mov    r0, r5
> > 49833-    b9e8:    4621          mov    r1, r4
> > 49834-    b9ea:    4623          mov    r3, r4
> > 49835-  /*
> > 49836-   *  WARNING!!! This is necessary to "kick" start the system and
> > 49837-   *             MUST be done before _Thread_Start is invoked.
> > 49838-   */
> > 49839-  cpu->heir      =
> > 49840:  cpu->executing = idle;
> > 49841-    b9ec:    60b5          str    r5, [r6, #8]
> > 49842-
> > 49843-  /*
> > 49844-   *  WARNING!!! This is necessary to "kick" start the system and
> > 49845-   *             MUST be done before _Thread_Start is invoked.
> > 49846-   */
> > 49847-  cpu->heir      =
> > 49848-    b9ee:    60f5          str    r5, [r6, #12]
> > 49849:  cpu->executing = idle;
> > 49850-
> > 49851-  _Thread_Start(
> > 49852-    b9f0:    f000 fee0     bl    c7b4 <_Thread_Start>
> > 49853-
> > 49854-    if ( _Per_CPU_Is_processor_started( cpu ) ) {
> > 49855:      _Thread_Create_idle_for_cpu( cpu );
> > 49856-    }
> > 49857-  }
> > 49858-}
> > 49859-    b9f4:    b009          add    sp, #36    ; 0x24
> > 49860-    b9f6:    bdf0          pop    {r4, r5, r6, r7, pc}
> > 49861-    b9f8:    200042c0     .word    0x200042c0
> > 49862-    b9fc:    000183c0     .word    0x000183c0
> > 49863-    ba00:    200011c0     .word    0x200011c0
> > 49864-    ba04:    200011bc     .word    0x200011bc
> > 49865-    ba08:    0001847c     .word    0x0001847c
> > 49866-    ba0c:    20004640     .word    0x20004640
> > 49867-    ba10:    49444c45     .word    0x49444c45
> > --
> > 54093-  const Scheduler_Control *scheduler,
> > 54094-  Thread_Control          *the_thread,
> > 54095-  Per_CPU_Control         *cpu
> > 54096-)
> > 54097-{
> > 54098:  ( *scheduler->Operations.start_idle )( scheduler, the_thread,
> cpu );
> > 54099-    c7de:    4809          ldr    r0, [pc, #36]    ; (c804
> > <_Thread_Start+0x50>)
> > 54100-      _Thread_Ready( the_thread );
> > 54101-    } else {
> > 54102-      const Scheduler_Control *scheduler = _Scheduler_Get_by_CPU(
> > cpu );
> > 54103-
> > 54104-      if ( scheduler != NULL ) {
> > 54105-        the_thread->current_state = STATES_READY;
> > 54106-    c7e0:    2200          movs    r2, #0
> > 54107-    c7e2:    612a          str    r2, [r5, #16]
> > 54108-    c7e4:    6b43          ldr    r3, [r0, #52]    ; 0x34
> > 54109-    c7e6:    4629          mov    r1, r5
> > 54110-    c7e8:    9a05          ldr    r2, [sp, #20]
> >
> > On Wed, Apr 24, 2019 at 2:59 PM Christian Mauderer
> > <christian.mauderer at embedded-brains.de
> > <mailto:christian.mauderer at embedded-brains.de>> wrote:
> >
> >     Am 24.04.19 um 02:35 schrieb Jython:
> >     > yes, I need to do low power for stm32f4
> >     > will this line work __asm__ volatile ("wfi");?
> >
> >     That line should be correct. Please note that the instruction is
> already
> >     used in the armv7 idle thread:
> >
> >
> https://git.rtems.org/rtems/tree/cpukit/score/cpu/arm/armv7-thread-idle.c#n32
> >
> >     The stm32f4 is a Cortex-M4 so it's quite likely that this routine is
> >     used. You can check by doing an "arm-rtems5-objdump -dS" on your file
> >     and search for the idle body.
> >
> >     With kind regards
> >
> >     Christian
> >
> >     >
> >     >
> >     > On Tue, Apr 23, 2019 at 10:28 PM Christian Mauderer
> >     > <christian.mauderer at embedded-brains.de
> >     <mailto:christian.mauderer at embedded-brains.de>
> >     > <mailto:christian.mauderer at embedded-brains.de
> >     <mailto:christian.mauderer at embedded-brains.de>>> wrote:
> >     >
> >     >     Am 22.04.19 um 09:47 schrieb Jython:
> >     >     > HI, ALL!
> >     >     > wfi
> >     >
> >
> http://www.keil.com/support/man/docs/armcc/armcc_chr1359125004400.htm
> >     >     > how can i call the arm __wfi?
> >     >     >
> >     >     > _______________________________________________
> >     >     > users mailing list
> >     >     > users at rtems.org <mailto:users at rtems.org>
> >     <mailto:users at rtems.org <mailto:users at rtems.org>>
> >     >     > http://lists.rtems.org/mailman/listinfo/users
> >     >     >
> >     >
> >     >     Hello Jython,
> >     >
> >     >     WFI is an assembler instruction. The Keil wrapper isn't
> >     available in
> >     >     gcc. I know of no direct replacement. Most likely you need a
> >     gcc inline
> >     >     assembly for that.
> >     >
> >     >     May I ask why you would need "wfi"? If you use a operating
> >     system, the
> >     >     system typically handles such low level stuff for you. The only
> >     >     application that springs to mind for that instruction is
> >     overwriting the
> >     >     idle loop to save energy.
> >     >
> >     >     Best regards
> >     >
> >     >     Christian
> >     >
> >     >     --
> >     >     --------------------------------------------
> >     >     embedded brains GmbH
> >     >     Herr Christian Mauderer
> >     >     Dornierstr. 4
> >     >     D-82178 Puchheim
> >     >     Germany
> >     >     email: christian.mauderer at embedded-brains.de
> >     <mailto:christian.mauderer at embedded-brains.de>
> >     >     <mailto:christian.mauderer at embedded-brains.de
> >     <mailto:christian.mauderer at embedded-brains.de>>
> >     >     Phone: +49-89-18 94 741 - 18
> >     >     Fax:   +49-89-18 94 741 - 08
> >     >     PGP: Public key available on request.
> >     >
> >     >     Diese Nachricht ist keine geschäftliche Mitteilung im Sinne
> >     des EHUG.
> >     >
> >
> >     --
> >     --------------------------------------------
> >     embedded brains GmbH
> >     Herr Christian Mauderer
> >     Dornierstr. 4
> >     D-82178 Puchheim
> >     Germany
> >     email: christian.mauderer at embedded-brains.de
> >     <mailto:christian.mauderer at embedded-brains.de>
> >     Phone: +49-89-18 94 741 - 18
> >     Fax:   +49-89-18 94 741 - 08
> >     PGP: Public key available on request.
> >
> >     Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
> >
>
> --
> --------------------------------------------
> embedded brains GmbH
> Herr Christian Mauderer
> Dornierstr. 4
> D-82178 Puchheim
> Germany
> email: christian.mauderer at embedded-brains.de
> Phone: +49-89-18 94 741 - 18
> Fax:   +49-89-18 94 741 - 08
> PGP: Public key available on request.
>
> Diese Nachricht ist keine geschäftliche Mitteilung im Sinne des EHUG.
>
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