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104 lines
3.1 KiB
104 lines
3.1 KiB
/* ***************************************************************************** |
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* The MIT License |
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* |
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* Copyright (c) 2010 Perry Hung. |
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* |
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* Permission is hereby granted, free of charge, to any person obtaining a copy |
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* of this software and associated documentation files (the "Software"), to deal |
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* in the Software without restriction, including without limitation the rights |
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
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* copies of the Software, and to permit persons to whom the Software is |
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* furnished to do so, subject to the following conditions: |
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* |
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* The above copyright notice and this permission notice shall be included in |
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* all copies or substantial portions of the Software. |
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* |
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN |
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* THE SOFTWARE. |
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* ****************************************************************************/ |
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# On an exception, push a fake stack thread mode stack frame and redirect |
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# thread execution to a thread mode error handler |
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# From RM008: |
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# The SP is decremented by eight words by the completion of the stack push. |
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# Figure 5-1 shows the contents of the stack after an exception pre-empts the |
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# current program flow. |
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# |
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# Old SP--> <previous> |
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# xPSR |
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# PC |
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# LR |
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# r12 |
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# r3 |
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# r2 |
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# r1 |
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# SP--> r0 |
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.text |
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.globl __exc_nmi |
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.weak __exc_nmi |
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.globl __exc_hardfault |
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.weak __exc_hardfault |
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.globl __exc_memmanage |
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.weak __exc_memmanage |
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.globl __exc_busfault |
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.weak __exc_busfault |
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.globl __exc_usagefault |
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.weak __exc_usagefault |
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.code 16 |
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.thumb_func |
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__exc_nmi: |
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mov r0, #1 |
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b __default_exc |
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.thumb_func |
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__exc_hardfault: |
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mov r0, #2 |
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b __default_exc |
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.thumb_func |
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__exc_memmanage: |
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mov r0, #3 |
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b __default_exc |
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.thumb_func |
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__exc_busfault: |
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mov r0, #4 |
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b __default_exc |
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.thumb_func |
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__exc_usagefault: |
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mov r0, #5 |
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b __default_exc |
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.thumb_func |
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__default_exc: |
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ldr r2, NVIC_CCR @ Enable returning to thread mode even if there are |
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mov r1 ,#1 @ pending exceptions. See flag NONEBASETHRDENA. |
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str r1, [r2] |
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cpsid i @ Disable global interrupts |
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ldr r2, SYSTICK_CSR @ Disable systick handler |
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mov r1, #0 |
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str r1, [r2] |
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ldr r1, CPSR_MASK @ Set default CPSR |
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push {r1} |
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ldr r1, TARGET_PC @ Set target pc |
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push {r1} |
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sub sp, sp, #24 @ Don't care |
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ldr r1, EXC_RETURN @ Return to thread mode |
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mov lr, r1 |
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bx lr @ Exception exit |
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.align 4 |
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CPSR_MASK: .word 0x61000000 |
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EXC_RETURN: .word 0xFFFFFFF9 |
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TARGET_PC: .word __error |
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NVIC_CCR: .word 0xE000ED14 @ NVIC configuration control register |
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SYSTICK_CSR: .word 0xE000E010 @ Systick control register
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