169 lines
4.5 KiB
ArmAsm
169 lines
4.5 KiB
ArmAsm
/* (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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.text
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.global _start
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.type _start, @function
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_start:
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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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/* 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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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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