libgcc/config/nds32/isr-library/reset.S

   1 /* c-isr library stuff of Andes NDS32 cpu for GNU compiler
   2    Copyright (C) 2012-2016 Free Software Foundation, Inc.
   3    Contributed by Andes Technology Corporation.
   4
   5    This file is part of GCC.
   6
   7    GCC is free software; you can redistribute it and/or modify it
   8    under the terms of the GNU General Public License as published
   9    by the Free Software Foundation; either version 3, or (at your
  10    option) any later version.
  11
  12    GCC is distributed in the hope that it will be useful, but WITHOUT
  13    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  14    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
  15    License for more details.
  16
  17    Under Section 7 of GPL version 3, you are granted additional
  18    permissions described in the GCC Runtime Library Exception, version
  19    3.1, as published by the Free Software Foundation.
  20
  21    You should have received a copy of the GNU General Public License and
  22    a copy of the GCC Runtime Library Exception along with this program;
  23    see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  24    <http://www.gnu.org/licenses/>.  */
  25
  26         .section .nds32_isr, "ax"       /* Put it in the section of 1st level handler.  */
  27         .align  1
  28         .weak   _SDA_BASE_      /* For reset handler only.  */
  29         .weak   _FP_BASE_       /* For reset handler only.  */
  30         .weak   _nds32_init_mem /* User defined memory initialization function.  */
  31         .globl  _start
  32         .globl  _nds32_reset
  33         .type   _nds32_reset, @function
  34 _nds32_reset:
  35 _start:
  36 #ifdef  NDS32_EXT_EX9
  37         .no_ex9_begin
  38 #endif
  39         /* Handle NMI and warm boot if any of them exists.  */
  40         beqz    $sp, 1f         /* Reset, NMI or warm boot?  */
  41         /* Either NMI or warm boot; save all regs.  */
  42
  43         /* Preserve registers for context-switching.  */
  44 #ifdef __NDS32_REDUCED_REGS__
  45         /* For 16-reg mode.  */
  46         smw.adm $r0, [$sp], $r10, #0x0
  47         smw.adm $r15, [$sp], $r15, #0xf
  48 #else
  49         /* For 32-reg mode.  */
  50         smw.adm $r0, [$sp], $r27, #0xf
  51 #endif
  52 #ifdef NDS32_EXT_IFC
  53         mfusr   $r1, $IFC_LP
  54         smw.adm $r1, [$sp], $r2, #0x0   /* Save extra $r2 to keep
  55                                            stack 8-byte alignment.  */
  56 #endif
  57
  58         la      $gp, _SDA_BASE_ /* Init GP for small data access.  */
  59         move    $r0, $sp        /* Init parameter.  */
  60         mfsr    $r1, $ITYPE     /* Check ITYPE for NMI or warm boot.  */
  61         andi    $r1, $r1, #0xf
  62         addi    $r1, $r1, #-1
  63         beqz    $r1, 2f         /* Warm boot if true.  */
  64         l.w     $r15, _nds32_nmih       /* Load NMI handler.  */
  65         j       3f
  66 2:
  67         l.w     $r15, _nds32_wrh        /* Load warm boot handler.  */
  68 3:
  69         beqz    $r15, 1f        /* If no handler, do cold boot.  */
  70         jral    $r15            /* Call handler.  */
  71         bnez    $r0, 1f         /* If fail to resume, do cold boot.  */
  72
  73         /* Restore registers for context-switching.  */
  74 #ifdef NDS32_EXT_IFC
  75         lmw.bim $r1, [$sp], $r2, #0x0   /* Restore extra $r2 to keep
  76                                            stack 8-byte alignment.  */
  77         mtusr   $r1, $IFC_LP
  78 #endif
  79 #ifdef __NDS32_REDUCED_REGS__
  80         /* For 16-reg mode.  */
  81         lmw.bim $r15, [$sp], $r15, #0xf
  82         lmw.bim $r0, [$sp], $r10, #0x0
  83 #else
  84         /* For 32-reg mode.  */
  85         lmw.bim $r0, [$sp], $r27, #0xf
  86 #endif
  87         iret    /* Resume operation.  */
  88
  89
  90 1:      /* Cold boot.  */
  91         /* Set IVB.ESZ = 1 (vector table entry size = 16 bytes)  */
  92         mfsr    $r0, $IVB
  93         li      $r1, #0xffff3fff
  94         and     $r0, $r0, $r1
  95         ori     $r0, $r0, #0x4000
  96         mtsr    $r0, $IVB
  97         dsb
  98
  99         la      $gp, _SDA_BASE_         /* Init $gp.  */
 100         la      $fp, _FP_BASE_          /* Init $fp.  */
 101         la      $sp, _stack             /* Init $sp.  */
 102 #ifdef  NDS32_EXT_EX9
 103 /*
 104  *      Initialize the table base of EX9 instruction
 105  *      ex9 generation needs to disable before the ITB is set
 106  */
 107         mfsr    $r0, $MSC_CFG   /* Check if HW support of EX9.  */
 108         srli    $r0, $r0, 24
 109         andi    $r0, $r0, 0x1
 110         beqz    $r0, 4f         /* Zero means HW does not support EX9.  */
 111         la      $r0, _ITB_BASE_ /* Init $ITB.  */
 112         mtusr   $r0, $ITB
 113         .no_ex9_end
 114 4:
 115 #endif
 116         la      $r15, _nds32_init_mem   /* Call DRAM init. _nds32_init_mem
 117                                           may written by C language.  */
 118         beqz    $r15, 6f
 119         jral    $r15
 120 6:
 121         l.w     $r15, _nds32_jmptbl_00  /* Load reset handler.  */
 122         jral    $r15
 123 /* Reset handler() should never return in a RTOS or non-OS system.
 124    In case it does return, an exception will be generated.
 125    This exception will be caught either by default break handler or by EDM.
 126    Default break handle may just do an infinite loop.
 127    EDM will notify GDB and GDB will regain control when the ID is 0x7fff. */
 128 5:
 129         break    #0x7fff
 130         .size   _nds32_reset, .-_nds32_reset