arch/powerpc/platforms/cell/spufs/spu_restore_crt0.S

   1 /*
   2  * crt0_r.S: Entry function for SPU-side context restore.
   3  *
   4  * Copyright (C) 2005 IBM
   5  *
   6  * Entry and exit function for SPU-side of the context restore
   7  * sequence.  Sets up an initial stack frame, then branches to
   8  * 'main'.  On return, restores all 128 registers from the LSCSA
   9  * and exits.
  10  *
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License as published by
  14  * the Free Software Foundation; either version 2, or (at your option)
  15  * any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  25  */
  26
  27 #include <asm/spu_csa.h>
  28
  29 .data
  30 .align 7
  31 .globl regs_spill
  32 regs_spill:
  33 .space SIZEOF_SPU_SPILL_REGS, 0x0
  34
  35 .text
  36 .global _start
  37 _start:
  38         /* Initialize the stack pointer to point to 16368
  39          * (16kb-16). The back chain pointer is initialized
  40          * to NULL.
  41          */
  42         il      $0, 0
  43         il      $SP, 16368
  44         stqd    $0, 0($SP)
  45
  46         /* Allocate a minimum stack frame for the called main.
  47          * This is needed so that main has a place to save the
  48          * link register when it calls another function.
  49          */
  50         stqd    $SP, -160($SP)
  51         ai      $SP, $SP, -160
  52
  53         /* Call the program's main function. */
  54         brsl    $0, main
  55
  56 .global exit
  57 .global _exit
  58 exit:
  59 _exit:
  60         /* SPU Context Restore, Step 5: Restore the remaining 112 GPRs. */
  61         ila     $3, regs_spill + 256
  62 restore_regs:
  63         lqr     $4, restore_reg_insts
  64 restore_reg_loop:
  65         ai      $4, $4, 4
  66         .balignl 16, 0x40200000
  67 restore_reg_insts:       /* must be quad-word aligned. */
  68         lqd     $16, 0($3)
  69         lqd     $17, 16($3)
  70         lqd     $18, 32($3)
  71         lqd     $19, 48($3)
  72         andi    $5, $4, 0x7F
  73         stqr    $4, restore_reg_insts
  74         ai      $3, $3, 64
  75         brnz    $5, restore_reg_loop
  76
  77         /* SPU Context Restore Step 17: Restore the first 16 GPRs. */
  78         lqa $0, regs_spill + 0
  79         lqa $1, regs_spill + 16
  80         lqa $2, regs_spill + 32
  81         lqa $3, regs_spill + 48
  82         lqa $4, regs_spill + 64
  83         lqa $5, regs_spill + 80
  84         lqa $6, regs_spill + 96
  85         lqa $7, regs_spill + 112
  86         lqa $8, regs_spill + 128
  87         lqa $9, regs_spill + 144
  88         lqa $10, regs_spill + 160
  89         lqa $11, regs_spill + 176
  90         lqa $12, regs_spill + 192
  91         lqa $13, regs_spill + 208
  92         lqa $14, regs_spill + 224
  93         lqa $15, regs_spill + 240
  94
  95         /* Under normal circumstances, the 'exit' function
  96          * terminates with 'stop SPU_RESTORE_COMPLETE',
  97          * indicating that the SPU-side restore code has
  98          * completed.
  99          *
 100          * However it is possible that instructions immediately
 101          * following the 'stop 0x3ffc' have been modified at run
 102          * time so as to recreate the exact SPU_Status settings
 103          * from the application, e.g. illegal instruciton, halt,
 104          * etc.
 105          */
 106 .global exit_fini
 107 .global _exit_fini
 108 exit_fini:
 109 _exit_fini:
 110         stop    SPU_RESTORE_COMPLETE
 111         stop    0
 112         stop    0
 113         stop    0
 114
 115         /* Pad the size of this crt0.o to be multiple of 16 bytes. */
 116 .balignl 16, 0x0