forked from Imagelibrary/rtems
216 lines
3.6 KiB
ArmAsm
216 lines
3.6 KiB
ArmAsm
/**
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* @file
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*
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* @brief Boot and system start code.
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*/
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/*
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* Copyright (c) 2008
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* Embedded Brains GmbH
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* Obere Lagerstr. 30
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* D-82178 Puchheim
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* Germany
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* rtems@embedded-brains.de
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*
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* The license and distribution terms for this file may be found in the file
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* LICENSE in this distribution or at http://www.rtems.com/license/LICENSE.
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*/
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#include <bsp/linker-symbols.h>
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#include <bsp/start.h>
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/* External symbols */
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.extern bsp_reset
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.extern boot_card
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/* Global symbols */
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.globl start
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.globl SWI_Handler
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/* Program Status Register definitions */
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.equ PSR_MODE_USR, 0x10
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.equ PSR_MODE_FIQ, 0x11
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.equ PSR_MODE_IRQ, 0x12
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.equ PSR_MODE_SVC, 0x13
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.equ PSR_MODE_ABT, 0x17
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.equ PSR_MODE_UNDEF, 0x1b
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.equ PSR_MODE_SYS, 0x1f
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.equ PSR_I, 0x80
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.equ PSR_F, 0x40
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.equ PSR_T, 0x20
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.arm
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.section ".bsp_start", "x"
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/*
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* This is the exception vector table and the pointers to the default
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* exceptions handlers.
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*/
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vector_block:
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ldr pc, handler_addr_reset
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ldr pc, handler_addr_undef
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ldr pc, handler_addr_swi
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ldr pc, handler_addr_prefetch
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ldr pc, handler_addr_abort
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/* Program signature checked by boot loader */
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.word 0xb8a06f58
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ldr pc, handler_addr_irq
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ldr pc, handler_addr_fiq
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handler_addr_reset:
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.word start
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handler_addr_undef:
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.word twiddle
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handler_addr_swi:
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.word twiddle
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handler_addr_prefetch:
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.word twiddle
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handler_addr_abort:
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.word twiddle
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handler_addr_reserved:
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.word twiddle
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handler_addr_irq:
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.word twiddle
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handler_addr_fiq:
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.word twiddle
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/* Start entry */
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start:
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/*
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* We do not save the context since we do not return to the boot
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* loader.
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*/
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/*
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* Set SVC mode, disable interrupts and enable ARM instructions.
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*/
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mov r0, #(PSR_MODE_SVC | PSR_I | PSR_F)
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msr cpsr, r0
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/* Initialize stack pointer registers for the various modes */
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/* Enter IRQ mode and set up the IRQ stack pointer */
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mov r0, #(PSR_MODE_IRQ | PSR_I | PSR_F)
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msr cpsr, r0
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ldr sp, =bsp_stack_irq_end
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/* Enter FIQ mode and set up the FIQ stack pointer */
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mov r0, #(PSR_MODE_FIQ | PSR_I | PSR_F)
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msr cpsr, r0
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ldr sp, =bsp_stack_fiq_end
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/* Enter ABT mode and set up the ABT stack pointer */
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mov r0, #(PSR_MODE_ABT | PSR_I | PSR_F)
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msr cpsr, r0
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ldr sp, =bsp_stack_abt_end
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/* Enter UNDEF mode and set up the UNDEF stack pointer */
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mov r0, #(PSR_MODE_UNDEF | PSR_I | PSR_F)
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msr cpsr, r0
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ldr sp, =bsp_stack_undef_end
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/* Enter SVC mode and set up the SVC stack pointer */
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mov r0, #(PSR_MODE_SVC | PSR_I | PSR_F)
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msr cpsr, r0
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ldr sp, =bsp_stack_svc_end
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/* Stay in SVC mode */
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/* Brach to start hook 0 */
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#ifdef __thumb__
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ldr r3, =bsp_start_hook_0
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mov lr, pc
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bx r3
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.thumb
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bx pc
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nop
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.arm
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#else
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bl bsp_start_hook_0
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#endif
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/*
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* Initialize the exception vectors. This includes the exceptions
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* vectors and the pointers to the default exception handlers.
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*/
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ldr r0, =bsp_section_vector_begin
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adr r1, vector_block
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ldmia r1!, {r2-r9}
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stmia r0!, {r2-r9}
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ldmia r1!, {r2-r9}
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stmia r0!, {r2-r9}
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/* Brach to start hook 1 */
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#ifdef __thumb__
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ldr r3, =bsp_start_hook_1
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mov lr, pc
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bx r3
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.thumb
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bx pc
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nop
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.arm
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#else
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bl bsp_start_hook_1
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#endif
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/* Brach to boot card */
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mov r0, #0
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#ifdef __thumb__
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ldr r3, =boot_card
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mov lr, pc
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bx r3
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.thumb
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bx pc
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nop
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.arm
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#else
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bl boot_card
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#endif
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/* Branch to reset function */
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#ifdef __thumb__
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ldr r3, =bsp_reset
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mov lr, pc
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bx r3
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.thumb
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bx pc
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nop
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.arm
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#else
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bl bsp_reset
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#endif
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/* Spin forever */
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SWI_Handler:
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twiddle:
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b twiddle
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