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Diffstat (limited to 'testing/examples/SAM7X256Test/src/crt.s')
| -rw-r--r-- | testing/examples/SAM7X256Test/src/crt.s | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/testing/examples/SAM7X256Test/src/crt.s b/testing/examples/SAM7X256Test/src/crt.s new file mode 100644 index 00000000..16e5865e --- /dev/null +++ b/testing/examples/SAM7X256Test/src/crt.s @@ -0,0 +1,225 @@ +/**************************************************************************** +* Copyright (c) 2006 by Michael Fischer. All rights reserved. +* +* Redistribution and use in source and binary forms, with or without +* modification, are permitted provided that the following conditions +* are met: +* +* 1. Redistributions of source code must retain the above copyright +* notice, this list of conditions and the following disclaimer. +* 2. Redistributions in binary form must reproduce the above copyright +* notice, this list of conditions and the following disclaimer in the +* documentation and/or other materials provided with the distribution. +* 3. Neither the name of the author nor the names of its contributors may +* be used to endorse or promote products derived from this software +* without specific prior written permission. +* +* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS +* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL +* THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, +* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, +* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS +* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED +* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF +* THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +* SUCH DAMAGE. +* +**************************************************************************** +* +* History: +* +* 18.12.06 mifi First Version +* The hardware initialization is based on the startup file +* crtat91sam7x256_rom.S from NutOS 4.2.1. +* Therefore partial copyright by egnite Software GmbH. +****************************************************************************/ + +/* + * Some defines for the program status registers + */ + ARM_MODE_USER = 0x10 /* Normal User Mode */ + ARM_MODE_FIQ = 0x11 /* FIQ Fast Interrupts Mode */ + ARM_MODE_IRQ = 0x12 /* IRQ Standard Interrupts Mode */ + ARM_MODE_SVC = 0x13 /* Supervisor Interrupts Mode */ + ARM_MODE_ABORT = 0x17 /* Abort Processing memory Faults Mode */ + ARM_MODE_UNDEF = 0x1B /* Undefined Instructions Mode */ + ARM_MODE_SYS = 0x1F /* System Running in Priviledged Operating Mode */ + ARM_MODE_MASK = 0x1F + + I_BIT = 0x80 /* disable IRQ when I bit is set */ + F_BIT = 0x40 /* disable IRQ when I bit is set */ + +/* + * Register Base Address + */ + AIC_BASE = 0xFFFFF000 + AIC_EOICR_OFF = 0x130 + AIC_IDCR_OFF = 0x124 + + RSTC_MR = 0xFFFFFD08 + RSTC_KEY = 0xA5000000 + RSTC_URSTEN = 0x00000001 + + WDT_BASE = 0xFFFFFD40 + WDT_MR_OFF = 0x00000004 + WDT_WDDIS = 0x00008000 + + MC_BASE = 0xFFFFFF00 + MC_FMR_OFF = 0x00000060 + MC_FWS_1FWS = 0x00480100 + + .section .vectors,"ax" + .code 32 + +/****************************************************************************/ +/* Vector table and reset entry */ +/****************************************************************************/ +_vectors: + ldr pc, ResetAddr /* Reset */ + ldr pc, UndefAddr /* Undefined instruction */ + ldr pc, SWIAddr /* Software interrupt */ + ldr pc, PAbortAddr /* Prefetch abort */ + ldr pc, DAbortAddr /* Data abort */ + ldr pc, ReservedAddr /* Reserved */ + ldr pc, IRQAddr /* IRQ interrupt */ + ldr pc, FIQAddr /* FIQ interrupt */ + + +ResetAddr: .word ResetHandler +UndefAddr: .word UndefHandler +SWIAddr: .word SWIHandler +PAbortAddr: .word PAbortHandler +DAbortAddr: .word DAbortHandler +ReservedAddr: .word 0 +IRQAddr: .word IRQHandler +FIQAddr: .word FIQHandler + + .ltorg + + .section .init, "ax" + .code 32 + + .global ResetHandler + .global ExitFunction + .extern main +/****************************************************************************/ +/* Reset handler */ +/****************************************************************************/ +ResetHandler: + /* + * The watchdog is enabled after processor reset. Disable it. + */ + ldr r1, =WDT_BASE + ldr r0, =WDT_WDDIS + str r0, [r1, #WDT_MR_OFF] + + + /* + * Enable user reset: assertion length programmed to 1ms + */ + ldr r0, =(RSTC_KEY | RSTC_URSTEN | (4 << 8)) + ldr r1, =RSTC_MR + str r0, [r1, #0] + + + /* + * Use 2 cycles for flash access. + */ + ldr r1, =MC_BASE + ldr r0, =MC_FWS_1FWS + str r0, [r1, #MC_FMR_OFF] + + + /* + * Disable all interrupts. Useful for debugging w/o target reset. + */ + ldr r1, =AIC_BASE + mvn r0, #0 + str r0, [r1, #AIC_EOICR_OFF] + str r0, [r1, #AIC_IDCR_OFF] + + + /* + * Setup a stack for each mode + */ + msr CPSR_c, #ARM_MODE_UNDEF | I_BIT | F_BIT /* Undefined Instruction Mode */ + ldr sp, =__stack_und_end + + msr CPSR_c, #ARM_MODE_ABORT | I_BIT | F_BIT /* Abort Mode */ + ldr sp, =__stack_abt_end + + msr CPSR_c, #ARM_MODE_FIQ | I_BIT | F_BIT /* FIQ Mode */ + ldr sp, =__stack_fiq_end + + msr CPSR_c, #ARM_MODE_IRQ | I_BIT | F_BIT /* IRQ Mode */ + ldr sp, =__stack_irq_end + + msr CPSR_c, #ARM_MODE_SVC | I_BIT | F_BIT /* Supervisor Mode */ + ldr sp, =__stack_svc_end + + + /* + * Clear .bss section + */ + ldr r1, =__bss_start + ldr r2, =__bss_end + ldr r3, =0 +bss_clear_loop: + cmp r1, r2 + strne r3, [r1], #+4 + bne bss_clear_loop + + + /* + * Jump to main + */ + mrs r0, cpsr + bic r0, r0, #I_BIT | F_BIT /* Enable FIQ and IRQ interrupt */ + msr cpsr, r0 + + mov r0, #0 /* No arguments */ + mov r1, #0 /* No arguments */ + ldr r2, =main + mov lr, pc + bx r2 /* And jump... */ + +ExitFunction: + nop + nop + nop + b ExitFunction + + +/****************************************************************************/ +/* Default interrupt handler */ +/****************************************************************************/ + +UndefHandler: + b UndefHandler + +SWIHandler: + b SWIHandler + +PAbortHandler: + b PAbortHandler + +DAbortHandler: + b DAbortHandler + +IRQHandler: + b IRQHandler + +FIQHandler: + b FIQHandler + + .weak ExitFunction + .weak UndefHandler, PAbortHandler, DAbortHandler + .weak IRQHandler, FIQHandler + + .ltorg +/*** EOF ***/ + + |