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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.17.0/] [libgloss/] [spu/] [crt0.S] - Blame information for rev 148

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1 148 jeremybenn
/* (C) Copyright IBM Corp. 2005, 2006
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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    * Redistributions of source code must retain the above copyright notice,
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this list of conditions and the following disclaimer.
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    * Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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    * Neither the name of IBM nor the names of its contributors may be
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used to endorse or promote products derived from this software without
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specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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/* crt0.S - entry function for C Runtime.
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 *
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 * With _STD_MAIN switch, the crt0.S will be compiled to crt2.o.
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 * The crt2.o sets up a C99-style interface for the SPU application's
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 * main() function, including a local copy of argv strings.
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 *
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 * The number of argument strings is passed in R3.  The size and EA
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 * location of the argument vector region is passed in R4.  Once the
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 * argv region is copied to the highest range of LS, and $SP is set
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 * just below it.
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 *
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 * Without _STD_MAIN, the crt0.S is compiled to crt1.o.
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 * The crt1.o prepares the entry for an SPU module. The main() function
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 * is called with different parameter list: spu_id, param and env
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 * are passed by R3, R4 and R5 respectively.
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 */
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#ifdef _STD_MAIN
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#define MFC_TAG_UPDATE_ALL      2
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#define MFC_GET_CMD             0x40
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#define TAGID                   0
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#define TAGMASK                 1
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#endif
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.comm __ea_local_store,16,16
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.text
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.global _start
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.type _start, @function
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_start:
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        /* Save the local store base from $6.  */
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        stqr $6, __ea_local_store
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#ifdef _STD_MAIN
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        /*
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         * Copy the argument vector region from EA to LS.  The DMA
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         * parameters are passed in R4:
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         *
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         *        +-------+-------+-------+-------+
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         *     R4 |   LS  | EA-HI | EA-LO | SIZE  |
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         *        +-------+-------+-------+-------+
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         *  word     0       1       2       3
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         *
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         * By the end of this sequence, the prefered slot (word 0) of
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         * R4 will contain the LS offset of argv region, which also
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         * serves as the base offset for $SP.
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         */
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        wrch    $MFC_LSA, $4
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        rotqbyi $4, $4, 4
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        wrch    $MFC_EAH, $4
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        rotqbyi $4, $4, 4
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        wrch    $MFC_EAL, $4
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        rotqbyi $4, $4, 4
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        wrch    $MFC_Size, $4
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        rotqbyi $4, $4, 4
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        il      $LR, TAGID
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        wrch    $MFC_TagID, $LR
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        /* Issue MFC_GET_CMD, then wait for transfer of argument
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         * vector region to complete.
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         */
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        il      $LR, MFC_GET_CMD
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        wrch    $MFC_Cmd, $LR
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        il      $LR, TAGMASK
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        wrch    $MFC_WrTagMask, $LR
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        il      $LR, MFC_TAG_UPDATE_ALL
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        wrch    $MFC_WrTagUpdate, $LR
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        rdch    $LR, $MFC_RdTagStat
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#endif
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        /* Save parameter list of main function to the non-volatile
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         * registers. spu_thread module has three parameters, while
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         * spulet only has two.
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         */
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        ori     $80, $3, 0
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        ori     $81, $4, 0
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#ifndef _STD_MAIN
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        ori     $82, $5, 0
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#endif
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        /* The Link Register is initialized to NULL.
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         */
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        il      $LR, 0
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#ifdef _STD_MAIN
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        /* For spulet, initialize stack pointer just below the argv region.
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         */
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        ai      $SP,$4,-16
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#else
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        /* For spe_thread module, the stack pointer is initialized
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         * below the area where __stack points to.
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         */
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        ila     $SP,__stack
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#endif
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        /* Initialize back chain to NULL.
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         */
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        stqd    $LR,0($SP)
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        /* Allocate 2 slots for stack frame.
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         */
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        stqd    $SP,-32($SP)
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        ai      $SP,$SP,-32
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        /* Save the Link Register in Link Register Save Area.
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         */
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        stqd    $LR,16($SP)
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        /* Calculate stack size.
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         */
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        ila     $3,_end
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        sf      $3,$3,$SP
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        rotqbyi $3,$3,12
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        /* The BE Linux ABI passes the stack size in $2, or use
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         * the default if $2 == 0.
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         */
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        rotqbyi $4,$2,12
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        ceqi    $5,$4,0
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        selb    $3,$4,$3,$5
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        fsmbi   $4,3840
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        selb    $SP,$SP,$3,$4
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        /* Call the _init function.
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         */
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        brsl    $LR, _init
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        /* Call the _fini function at exit time.
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         */
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        ila     $3, _fini
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        brsl    $LR, atexit
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#ifdef _PROFILE
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        /* Call monstartup if profiling is enabled
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         */
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        brsl    $LR, __monstartup
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#endif
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        ori     $3,$80,0
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        ori     $4,$81,0
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#ifndef _STD_MAIN
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        ori     $5,$82,0
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#endif
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        /* Call the programs main.
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         */
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        brsl    $LR, main
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        /* Call exit.
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         */
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        brsl    $LR, exit
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