working store & restore
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011d784923
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991b088b0d
10
at91_init0.s
10
at91_init0.s
@ -29,6 +29,7 @@
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.equ ARM_MODE_IRQ, 0x12
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.equ ARM_MODE_SVC, 0x13
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.equ ARM_MODE_ABT, 0x17
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.equ ARM_MODE_SYS, 0x1F
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.equ I_BIT, 0x80
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.equ F_BIT, 0x40
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@ -46,10 +47,11 @@ rsvdvec: ldr pc, [pc, #24] /* 0x14 reserved */
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irqvec: ldr pc, [pc, #24] /* 0x18 IRQ */
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fiqvec: ldr pc, [pc, #24] /* 0x1c FIQ */
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.extern SWI_Handler
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/* 0x80000000 will result in Prefetch Abort */
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.word InitReset
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.word 0x80000000
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.word 0x80000000
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.word SWI_Handler
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.word ABT_Handler_Entry
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.word ABT_Handler_Entry
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.word 0x80000000
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@ -88,7 +90,7 @@ InitReset:
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sub r0, r0, #ABT_Stack_Size
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/* Setup Supervisor Mode Stack (IRQ & NMI enabled) */
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msr CPSR_c, #ARM_MODE_SVC
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msr CPSR_c, #ARM_MODE_SYS
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mov sp, r0
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/* Relocate .data section */
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@ -167,7 +169,7 @@ FIQ_Handler_Entry:
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ldr r0, [r8, #AIC_FVR]
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/* Switch to ARM_MODE_SVC and save registers there */
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msr CPSR_c, #ARM_MODE_SVC | I_BIT | F_BIT
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msr CPSR_c, #ARM_MODE_SYS | I_BIT | F_BIT
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stmfd sp!, { r1-r3, r12, lr }
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/* execute FIQ in SVC_MODE */
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@ -208,7 +210,7 @@ IRQ_Handler_Entry:
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str r14, [r14, #AIC_IVR]
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/* Enable Interrupt and Switch in Supervisor Mode */
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msr CPSR_c, #ARM_MODE_SVC
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msr CPSR_c, #ARM_MODE_SYS
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/* Save scratch/used registers and LR in User Stack */
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stmfd sp!, { r1-r3, r12, r14 }
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153
main.c
153
main.c
@ -18,6 +18,7 @@
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***************************************************************************/
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#include <stdint.h>
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#include <stdio.h>
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#include <string.h>
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#include "AT91SAM7S256.h"
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#include "board.h"
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@ -25,65 +26,136 @@
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#include "at91_dbgu.h"
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#include "memalloc.h"
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uint32_t * init_ctx(uint32_t *stack, void *code, void *arg)
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struct register_context {
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uint32_t r0;
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uint32_t r1;
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uint32_t pc;
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uint32_t cpsr;
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uint32_t r2;
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uint32_t r3;
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uint32_t r4;
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uint32_t r5;
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uint32_t r6;
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uint32_t r7;
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uint32_t r8;
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uint32_t r9;
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uint32_t r10;
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uint32_t r11;
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uint32_t r12;
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uint32_t sp;
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uint32_t r14;
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};
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struct context {
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struct register_context regs;
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uint32_t stacksize;
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};
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struct context * create_ctx(uint32_t stacksize, void *code, void *arg)
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{
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uint32_t org_stack = (uint32_t)stack;
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void *stack = static_alloc(sizeof(struct context) + stacksize);
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memset(stack, 0, stacksize);
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*stack-- = (uint32_t) code; // r15 (pc)
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*stack-- = 0x14141414; // r14 (lr)
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*stack-- = org_stack -4; // r13 (sp)
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*stack-- = 0x12121212; // r12
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*stack-- = 0x11111111; // r11
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*stack-- = 0x10101010; // r10
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*stack-- = 0x09090909; // r9
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*stack-- = 0x08080808; // r8
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*stack-- = 0x07070707; // r7
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*stack-- = 0x06060606; // r6
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*stack-- = 0x05050505; // r5
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*stack-- = 0x04040404; // r4
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*stack-- = 0x03030303; // r3
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*stack-- = 0x02020202; // r2
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*stack-- = 0x01010101; // r1
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*stack-- = (uint32_t) arg; // r0 (function parameter)
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*stack = 0xF0000013; // SPSR (SVC, ARM, IRQ & FIQ enabled)
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struct context *ctx = (struct context *)((uint8_t *)stack + stacksize);
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ctx->regs.r0 = (uint32_t)arg;
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ctx->regs.pc = (uint32_t)code;
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ctx->regs.cpsr = 0x0000001F;
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ctx->regs.sp = (uint32_t)ctx;
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return stack;
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ctx->regs.r1 = 0x01010101;
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ctx->regs.r2 = 0x02020202;
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ctx->regs.r3 = 0x03030303;
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ctx->regs.r4 = 0x04040404;
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ctx->regs.r5 = 0x05050505;
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ctx->regs.r6 = 0x06060606;
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ctx->regs.r7 = 0x07070707;
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ctx->regs.r8 = 0x08080808;
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ctx->regs.r9 = 0x09090909;
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ctx->regs.r10 = 0x10101010;
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ctx->regs.r11 = 0x11111111;
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ctx->regs.r12 = 0x12121212;
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ctx->regs.r14 = 0x14141414;
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return ctx;
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}
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struct context *current_ctx;
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/* we're in the scheduler, SVC mode */
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void restore_ctx(uint32_t *stack)
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void restore_ctx(void)
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{
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asm volatile (
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/* restore spsr */
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"mov lr, r0 \n\t"
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"ldmia lr!, {r0} \n\t"
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"msr spsr, r0 \n\t"
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// debug: assume we're in svc mode
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"msr cpsr_c, 0x13 \n\r"
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/* restore all registers */
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"ldmia lr, {r0-r13} \n\t"
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"nop \n\t"
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"ldmia sp!, {r14-r15}^ \n\t"
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"ldr r0, =current_ctx \n\t"
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"ldr r0, [r0] \n\t"
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// get r0, r1 and pc(in lr)
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"ldmia r0!, {r1-r2,r14} \n\t"
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// put r0, r1 on (svc)stack
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"stmdb sp!, {r1-r2} \n\t"
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// get spsr(in r1), r2-r14 (usermode!)
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"ldmia r0, {r1-r14}^ \n\t"
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"nop \n\t"
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// store spsr
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"msr spsr, r1 \n\t"
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// get r0 & r1 from (svc)stack
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"ldmia sp!, {r0, r1} \n\t"
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// jump & restore cpsr from spsr
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"movs pc, lr \n\t"
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);
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}
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void store_ctx(void)
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__attribute__((naked)) void SWI_Handler(void)
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{
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asm volatile (
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/* push r0 on (task)stack */
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"stmdb sp!, {r0} \n\r"
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"stmdb sp!, {r0-r1} \n\t"
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// TODO: fill r0 with address TCB
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"ldr r0, =current_ctx \n\t"
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"ldr r0, [r0] \n\t"
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"add r0, r0, #68 \n\t"
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/* return address */
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"stmdb r0!, {lr} \n\r"
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"mrs r1, spsr \n\t"
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"stmdb r0, {r1-r14}^ \n\t"
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"nop \n\t"
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"sub r0, r0, #56 \n\t"
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"ldmia sp!, {r1, r2} \n\t"
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"stmdb r0!, {r1, r2, r14} \n\t"
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);
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printf("swi: ok\n\r");
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asm volatile (
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"ldr r0, =current_ctx \n\t"
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"ldr r0, [r0] \n\t"
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"ldmia r0!, {r1-r2,r14} \n\t"
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"stmdb sp!, {r1-r2} \n\t"
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"ldmia r0, {r1-r14}^ \n\t"
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"nop \n\t"
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"msr spsr, r1 \n\t"
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"ldmia sp!, {r0, r1} \n\t"
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"movs pc, lr \n\t"
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);
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}
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void testfunc(void *p)
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{
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printf("bla: %p\n\r", p);
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printf("testfunc: %p\n\r", p);
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asm volatile ("swi");
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printf("testfunc: %p\n\r", p);
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while(1);
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}
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@ -97,9 +169,6 @@ int main(void)
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at91_dbgu_init();
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at91_dbgu_puts("==========================================================\n\rGood morning Dave\n\r");
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uint32_t *blub = static_alloc(1024);
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printf("blub: %p\n\r", blub);
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uint32_t *tmp = init_ctx(blub + (1024/4), testfunc, 0);
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restore_ctx(tmp);
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current_ctx = create_ctx(1024, testfunc, 0);
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restore_ctx();
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}
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