/*
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* crt0_r.S: Entry function for SPU-side context restore.
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*
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* Copyright (C) 2005 IBM
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*
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* Entry and exit function for SPU-side of the context restore
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* sequence. Sets up an initial stack frame, then branches to
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* 'main'. On return, restores all 128 registers from the LSCSA
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* and exits.
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*
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <asm/spu_csa.h>
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.data
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.align 7
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.globl regs_spill
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regs_spill:
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.space SIZEOF_SPU_SPILL_REGS, 0x0
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.text
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.global _start
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_start:
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/* Initialize the stack pointer to point to 16368
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* (16kb-16). The back chain pointer is initialized
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* to NULL.
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*/
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il $0, 0
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il $SP, 16368
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stqd $0, 0($SP)
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/* Allocate a minimum stack frame for the called main.
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* This is needed so that main has a place to save the
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* link register when it calls another function.
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*/
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stqd $SP, -160($SP)
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ai $SP, $SP, -160
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/* Call the program's main function. */
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brsl $0, main
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.global exit
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.global _exit
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exit:
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_exit:
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/* SPU Context Restore, Step 5: Restore the remaining 112 GPRs. */
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ila $3, regs_spill + 256
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restore_regs:
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lqr $4, restore_reg_insts
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restore_reg_loop:
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ai $4, $4, 4
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.balignl 16, 0x40200000
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restore_reg_insts: /* must be quad-word aligned. */
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lqd $16, 0($3)
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lqd $17, 16($3)
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lqd $18, 32($3)
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lqd $19, 48($3)
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andi $5, $4, 0x7F
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stqr $4, restore_reg_insts
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ai $3, $3, 64
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brnz $5, restore_reg_loop
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/* SPU Context Restore Step 17: Restore the first 16 GPRs. */
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lqa $0, regs_spill + 0
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lqa $1, regs_spill + 16
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lqa $2, regs_spill + 32
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lqa $3, regs_spill + 48
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lqa $4, regs_spill + 64
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lqa $5, regs_spill + 80
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lqa $6, regs_spill + 96
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lqa $7, regs_spill + 112
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lqa $8, regs_spill + 128
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lqa $9, regs_spill + 144
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lqa $10, regs_spill + 160
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lqa $11, regs_spill + 176
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lqa $12, regs_spill + 192
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lqa $13, regs_spill + 208
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lqa $14, regs_spill + 224
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lqa $15, regs_spill + 240
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/* Under normal circumstances, the 'exit' function
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* terminates with 'stop SPU_RESTORE_COMPLETE',
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* indicating that the SPU-side restore code has
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* completed.
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*
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* However it is possible that instructions immediately
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* following the 'stop 0x3ffc' have been modified at run
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* time so as to recreate the exact SPU_Status settings
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* from the application, e.g. illegal instruciton, halt,
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* etc.
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*/
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.global exit_fini
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.global _exit_fini
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exit_fini:
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_exit_fini:
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stop SPU_RESTORE_COMPLETE
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stop 0
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stop 0
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stop 0
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/* Pad the size of this crt0.o to be multiple of 16 bytes. */
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.balignl 16, 0x0
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