224 lines
6.7 KiB
ArmAsm
224 lines
6.7 KiB
ArmAsm
/****************************************************************************
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* Copyright (c) 2006 by Michael Fischer. All rights reserved.
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*
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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
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. 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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* 3. Neither the name of the author nor the names of its contributors may
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* be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
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* THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
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* THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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****************************************************************************
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*
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* History:
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*
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* 18.12.06 mifi First Version
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* The hardware initialization is based on the startup file
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* crtat91sam7x256_rom.S from NutOS 4.2.1.
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* Therefore partial copyright by egnite Software GmbH.
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****************************************************************************/
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/*
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* Some defines for the program status registers
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*/
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ARM_MODE_USER = 0x10 /* Normal User Mode */
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ARM_MODE_FIQ = 0x11 /* FIQ Fast Interrupts Mode */
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ARM_MODE_IRQ = 0x12 /* IRQ Standard Interrupts Mode */
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ARM_MODE_SVC = 0x13 /* Supervisor Interrupts Mode */
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ARM_MODE_ABORT = 0x17 /* Abort Processing memory Faults Mode */
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ARM_MODE_UNDEF = 0x1B /* Undefined Instructions Mode */
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ARM_MODE_SYS = 0x1F /* System Running in Priviledged Operating Mode */
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ARM_MODE_MASK = 0x1F
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I_BIT = 0x80 /* disable IRQ when I bit is set */
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F_BIT = 0x40 /* disable IRQ when I bit is set */
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/*
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* Register Base Address
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*/
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AIC_BASE = 0xFFFFF000
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AIC_EOICR_OFF = 0x130
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AIC_IDCR_OFF = 0x124
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RSTC_MR = 0xFFFFFD08
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RSTC_KEY = 0xA5000000
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RSTC_URSTEN = 0x00000001
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WDT_BASE = 0xFFFFFD40
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WDT_MR_OFF = 0x00000004
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WDT_WDDIS = 0x00008000
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MC_BASE = 0xFFFFFF00
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MC_FMR_OFF = 0x00000060
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MC_FWS_1FWS = 0x00480100
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.section .vectors,"ax"
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.code 32
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/****************************************************************************/
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/* Vector table and reset entry */
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/****************************************************************************/
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_vectors:
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ldr pc, ResetAddr /* Reset */
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ldr pc, UndefAddr /* Undefined instruction */
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ldr pc, SWIAddr /* Software interrupt */
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ldr pc, PAbortAddr /* Prefetch abort */
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ldr pc, DAbortAddr /* Data abort */
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ldr pc, ReservedAddr /* Reserved */
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ldr pc, IRQAddr /* IRQ interrupt */
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ldr pc, FIQAddr /* FIQ interrupt */
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ResetAddr: .word ResetHandler
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UndefAddr: .word UndefHandler
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SWIAddr: .word SWIHandler
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PAbortAddr: .word PAbortHandler
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DAbortAddr: .word DAbortHandler
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ReservedAddr: .word 0
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IRQAddr: .word IRQHandler
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FIQAddr: .word FIQHandler
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.ltorg
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.section .init, "ax"
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.code 32
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.global ResetHandler
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.global ExitFunction
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.extern main
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/****************************************************************************/
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/* Reset handler */
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/****************************************************************************/
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ResetHandler:
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/*
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* The watchdog is enabled after processor reset. Disable it.
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*/
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ldr r1, =WDT_BASE
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ldr r0, =WDT_WDDIS
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str r0, [r1, #WDT_MR_OFF]
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/*
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* Enable user reset: assertion length programmed to 1ms
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*/
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ldr r0, =(RSTC_KEY | RSTC_URSTEN | (4 << 8))
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ldr r1, =RSTC_MR
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str r0, [r1, #0]
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/*
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* Use 2 cycles for flash access.
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*/
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ldr r1, =MC_BASE
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ldr r0, =MC_FWS_1FWS
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str r0, [r1, #MC_FMR_OFF]
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/*
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* Disable all interrupts. Useful for debugging w/o target reset.
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*/
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ldr r1, =AIC_BASE
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mvn r0, #0
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str r0, [r1, #AIC_EOICR_OFF]
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str r0, [r1, #AIC_IDCR_OFF]
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/*
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* Setup a stack for each mode
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*/
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msr CPSR_c, #ARM_MODE_UNDEF | I_BIT | F_BIT /* Undefined Instruction Mode */
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ldr sp, =__stack_und_end
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msr CPSR_c, #ARM_MODE_ABORT | I_BIT | F_BIT /* Abort Mode */
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ldr sp, =__stack_abt_end
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msr CPSR_c, #ARM_MODE_FIQ | I_BIT | F_BIT /* FIQ Mode */
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ldr sp, =__stack_fiq_end
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msr CPSR_c, #ARM_MODE_IRQ | I_BIT | F_BIT /* IRQ Mode */
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ldr sp, =__stack_irq_end
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msr CPSR_c, #ARM_MODE_SVC | I_BIT | F_BIT /* Supervisor Mode */
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ldr sp, =__stack_svc_end
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/*
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* Clear .bss section
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*/
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ldr r1, =__bss_start
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ldr r2, =__bss_end
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ldr r3, =0
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bss_clear_loop:
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cmp r1, r2
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strne r3, [r1], #+4
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bne bss_clear_loop
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/*
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* Jump to main
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*/
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mrs r0, cpsr
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bic r0, r0, #I_BIT | F_BIT /* Enable FIQ and IRQ interrupt */
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msr cpsr, r0
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mov r0, #0 /* No arguments */
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mov r1, #0 /* No arguments */
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ldr r2, =main
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mov lr, pc
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bx r2 /* And jump... */
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ExitFunction:
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nop
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nop
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nop
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b ExitFunction
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/****************************************************************************/
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/* Default interrupt handler */
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/****************************************************************************/
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UndefHandler:
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b UndefHandler
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SWIHandler:
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b SWIHandler
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PAbortHandler:
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b PAbortHandler
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DAbortHandler:
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b DAbortHandler
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IRQHandler:
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b IRQHandler
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FIQHandler:
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b FIQHandler
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.weak ExitFunction
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.weak UndefHandler, PAbortHandler, DAbortHandler
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.weak IRQHandler, FIQHandler
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.ltorg
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/*** EOF ***/
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