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Diffstat (limited to 'libmaple/exc.S')
| -rw-r--r-- | libmaple/exc.S | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/libmaple/exc.S b/libmaple/exc.S new file mode 100644 index 0000000..7631e48 --- /dev/null +++ b/libmaple/exc.S @@ -0,0 +1,101 @@ +/* ***************************************************************************** + * The MIT License + * + * Copyright (c) 2010 Perry Hung. + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + * ****************************************************************************/ + +# On an exception, push a fake stack thread mode stack frame and redirect +# thread execution to a thread mode error handler + +# From RM008: +# The SP is decremented by eight words by the completion of the stack push. +# Figure 5-1 shows the contents of the stack after an exception pre-empts the +# current program flow. +# +# Old SP--> <previous> +# xPSR +# PC +# LR +# r12 +# r3 +# r2 +# r1 +# SP--> r0 + +.text +.globl __exc_hardfault +.globl __exc_nmi +.globl __exc_hardfault +.globl __exc_memmanage +.globl __exc_busfault +.globl __exc_usagefault + +.code 16 +.thumb_func +__exc_nmi: + mov r0, #1 + b __default_exc + +.thumb_func +__exc_hardfault: + mov r0, #2 + b __default_exc + +.thumb_func +__exc_memmanage: + mov r0, #3 + b __default_exc + +.thumb_func +__exc_busfault: + mov r0, #4 + b __default_exc + +.thumb_func +__exc_usagefault: + mov r0, #5 + b __default_exc + +.thumb_func +__default_exc: + ldr r2, NVIC_CCR @ Enable returning to thread mode even if there are + mov r1 ,#1 @ pending exceptions. See flag NONEBASETHRDENA. + str r1, [r2] + cpsid i @ Disable global interrupts + ldr r2, SYSTICK_CSR @ Disable systick handler + mov r1, #0 + str r1, [r2] + ldr r1, CPSR_MASK @ Set default CPSR + push {r1} + ldr r1, TARGET_PC @ Set target pc + push {r1} + sub sp, sp, #24 @ Don't care + ldr r1, EXC_RETURN @ Return to thread mode + mov lr, r1 + bx lr @ Exception exit + +.align 4 +CPSR_MASK: .word 0x61000000 +EXC_RETURN: .word 0xFFFFFFF9 +TARGET_PC: .word __error +NVIC_CCR: .word 0xE000ED14 @ NVIC configuration control register +SYSTICK_CSR: .word 0xE000E010 @ Systick control register + |