src/soc/litex/crt0.S

   1 /* Copyright 2013-2014 IBM Corp.
   2  *
   3  * Licensed under the Apache License, Version 2.0 (the "License");
   4  * you may not use this file except in compliance with the License.
   5  * You may obtain a copy of the License at
   6  *
   7  *      http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Unless required by applicable law or agreed to in writing, software
  10  * distributed under the License is distributed on an "AS IS" BASIS,
  11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
  12  * implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #define FIXUP_ENDIAN                                               \
  18         tdi   0,0,0x48;   /* Reverse endian of b . + 8          */ \
  19         b     191f;       /* Skip trampoline if endian is good  */ \
  20         .long 0xa600607d; /* mfmsr r11                          */ \
  21         .long 0x01006b69; /* xori r11,r11,1                     */ \
  22         .long 0x05009f42; /* bcl 20,31,$+4                      */ \
  23         .long 0xa602487d; /* mflr r10                           */ \
  24         .long 0x14004a39; /* addi r10,r10,20                    */ \
  25         .long 0xa64b5a7d; /* mthsrr0 r10                        */ \
  26         .long 0xa64b7b7d; /* mthsrr1 r11                        */ \
  27         .long 0x2402004c; /* hrfid                              */ \
  28 191:
  29
  30
  31 /* Load an immediate 64-bit value into a register */
  32 #define LOAD_IMM64(r, e)                        \
  33         lis     r,(e)@highest;                  \
  34         ori     r,r,(e)@higher;                 \
  35         rldicr  r,r, 32, 31;                    \
  36         oris    r,r, (e)@h;                     \
  37         ori     r,r, (e)@l;
  38
  39         . = 0
  40 .global _start
  41 _start:
  42         FIXUP_ENDIAN
  43
  44         /* setup stack */
  45         LOAD_IMM64(%r1, _fstack - 0x100)
  46         LOAD_IMM64(%r12, main)
  47         mtctr   %r12,
  48         bctrl
  49         b .
  50
  51 #define EXCEPTION(nr)           \
  52         .=  nr;      \
  53         b       .
  54
  55         /* More exception stubs */
  56         EXCEPTION(0x100)
  57         EXCEPTION(0x200)
  58         EXCEPTION(0x300)
  59         EXCEPTION(0x380)
  60         EXCEPTION(0x400)
  61         EXCEPTION(0x480)
  62         EXCEPTION(0x500)
  63         EXCEPTION(0x600)
  64         EXCEPTION(0x700)
  65         EXCEPTION(0x800)
  66         EXCEPTION(0x900)
  67         EXCEPTION(0x980)
  68         EXCEPTION(0xa00)
  69         EXCEPTION(0xb00)
  70         EXCEPTION(0xc00)
  71         EXCEPTION(0xd00)
  72         EXCEPTION(0xe00)
  73         EXCEPTION(0xe20)
  74         EXCEPTION(0xe40)
  75         EXCEPTION(0xe60)
  76         EXCEPTION(0xe80)
  77         EXCEPTION(0xf00)
  78         EXCEPTION(0xf20)
  79         EXCEPTION(0xf40)
  80         EXCEPTION(0xf60)
  81         EXCEPTION(0xf80)
  82 #if 0
  83         EXCEPTION(0x1000)
  84         EXCEPTION(0x1100)
  85         EXCEPTION(0x1200)
  86         EXCEPTION(0x1300)
  87         EXCEPTION(0x1400)
  88         EXCEPTION(0x1500)
  89         EXCEPTION(0x1600)
  90 #endif
  91
  92         .text
  93