/* * File : start_gcc.S * This file is part of RT-Thread RTOS * COPYRIGHT (C) 2013-2018, RT-Thread Development Team */ .equ MODE_USR, 0x10 .equ MODE_FIQ, 0x11 .equ MODE_IRQ, 0x12 .equ MODE_SVC, 0x13 .equ MODE_ABT, 0x17 .equ MODE_UND, 0x1B .equ MODE_SYS, 0x1F .equ MODEMASK, 0x1F .equ NOINT, 0xC0 .equ I_BIT, 0x80 .equ F_BIT, 0x40 .equ UND_STACK_SIZE, 0x00000100 .equ SVC_STACK_SIZE, 0x00000100 .equ ABT_STACK_SIZE, 0x00000100 .equ FIQ_STACK_SIZE, 0x00000100 .equ IRQ_STACK_SIZE, 0x00000100 .equ SYS_STACK_SIZE, 0x00000100 /* *************************************** * Interrupt vector table *************************************** */ .section .vectors .code 32 .global system_vectors system_vectors: ldr pc, _vector_reset ldr pc, _vector_undef ldr pc, _vector_swi ldr pc, _vector_pabt ldr pc, _vector_dabt ldr pc, _vector_resv ldr pc, _vector_irq ldr pc, _vector_fiq _vector_reset: .word reset _vector_undef: .word vector_undef _vector_swi: .word SVC_Handler _vector_pabt: .word vector_pabt _vector_dabt: .word vector_dabt _vector_resv: .word vector_resv _vector_irq: .word vector_irq _vector_fiq: .word vector_fiq .balignl 16,0xdeadbeef /* *************************************** * Stack and Heap Definitions *************************************** */ .section .data .space UND_STACK_SIZE .align 3 .global und_stack_start und_stack_start: .space ABT_STACK_SIZE .align 3 .global abt_stack_start abt_stack_start: .space FIQ_STACK_SIZE .align 3 .global fiq_stack_start fiq_stack_start: .space IRQ_STACK_SIZE .align 3 .global irq_stack_start irq_stack_start: .skip SYS_STACK_SIZE .align 3 .global sys_stack_start sys_stack_start: .space SVC_STACK_SIZE .align 3 .global svc_stack_start svc_stack_start: /* *************************************** * Startup Code *************************************** */ .section .text .global reset reset: /* Enter svc mode and mask interrupts */ mrs r0, cpsr bic r0, r0, #MODEMASK orr r0, r0, #MODE_SVC|NOINT msr cpsr_cxsf, r0 /* init cpu */ bl cpu_init_crit /* todo:copyself to link address */ /* Copy vector to the correct address */ ldr r0, =system_vectors mrc p15, 0, r2, c1, c0, 0 ands r2, r2, #(1 << 13) ldreq r1, =0x00000000 ldrne r1, =0xffff0000 ldmia r0!, {r2-r8, r10} stmia r1!, {r2-r8, r10} ldmia r0!, {r2-r8, r10} stmia r1!, {r2-r8, r10} /* turn off the watchdog */ ldr r0, =0x01C20CB8 mov r1, #0x0 str r1, [r0] /* mask all IRQs source */ ldr r1, =0xffffffff ldr r0, =0x01C20430 str r1, [r0], #0x04 str r1, [r0] /* Call low level init function */ ldr sp, =svc_stack_start ldr r0, =rt_low_level_init blx r0 /* init stack */ bl stack_setup /* clear bss */ mov r0, #0 ldr r1, =__bss_start ldr r2, =__bss_end bss_clear_loop: cmp r1, r2 strlo r0, [r1], #4 blo bss_clear_loop /* call c++ constructors of global objects */ /* ldr r0, =__ctors_start__ ldr r1, =__ctors_end__ ctor_loop: cmp r0, r1 beq ctor_end ldr r2, [r0], #4 stmfd sp!, {r0-r1} mov lr, pc bx r2 ldmfd sp!, {r0-r1} b ctor_loop ctor_end: */ /* start RT-Thread Kernel */ ldr pc, _rtthread_startup _rtthread_startup: .word rtthread_startup cpu_init_crit: /* invalidate I/D caches */ mov r0, #0 mcr p15, 0, r0, c7, c7, 0 mcr p15, 0, r0, c8, c7, 0 /* disable MMU stuff and caches */ mrc p15, 0, r0, c1, c0, 0 bic r0, r0, #0x00002300 bic r0, r0, #0x00000087 orr r0, r0, #0x00000002 orr r0, r0, #0x00001000 mcr p15, 0, r0, c1, c0, 0 bx lr stack_setup: /* Setup Stack for each mode */ mrs r0, cpsr bic r0, r0, #MODEMASK orr r1, r0, #MODE_UND|NOINT msr cpsr_cxsf, r1 ldr sp, =und_stack_start orr r1, r0, #MODE_ABT|NOINT msr cpsr_cxsf, r1 ldr sp, =abt_stack_start orr r1, r0, #MODE_IRQ|NOINT msr cpsr_cxsf, r1 ldr sp, =irq_stack_start orr r1, r0, #MODE_FIQ|NOINT msr cpsr_cxsf, r1 ldr sp, =fiq_stack_start orr r1, r0, #MODE_SYS|NOINT msr cpsr_cxsf,r1 ldr sp, =sys_stack_start orr r1, r0, #MODE_SVC|NOINT msr cpsr_cxsf, r1 ldr sp, =svc_stack_start bx lr /* *************************************** * exception handlers *************************************** */ .global rt_hw_trap_udef .global rt_hw_trap_swi .global rt_hw_trap_pabt .global rt_hw_trap_dabt .global rt_hw_trap_resv .global rt_hw_trap_irq .global rt_hw_trap_fiq .global rt_interrupt_enter .global rt_interrupt_leave .global rt_thread_switch_interrupt_flag .global rt_interrupt_from_thread .global rt_interrupt_to_thread /* Interrupt */ .align 5 vector_fiq: stmfd sp!,{r0-r7,lr} bl rt_hw_trap_fiq ldmfd sp!,{r0-r7,lr} subs pc, lr, #4 .align 5 vector_irq: stmfd sp!, {r0-r12,lr} bl rt_interrupt_enter bl rt_hw_trap_irq bl rt_interrupt_leave ldr r0, =rt_thread_switch_interrupt_flag ldr r1, [r0] cmp r1, #1 beq rt_hw_context_switch_interrupt_do ldmfd sp!, {r0-r12,lr} subs pc, lr, #4 rt_hw_context_switch_interrupt_do: mov r1, #0 str r1, [r0] mov r1, sp add sp, sp, #4*4 ldmfd sp!, {r4-r12,lr} mrs r0, spsr sub r2, lr, #4 msr cpsr_c, #I_BIT|F_BIT|MODE_SVC stmfd sp!, {r2} stmfd sp!, {r4-r12,lr} ldmfd r1, {r1-r4} stmfd sp!, {r1-r4} stmfd sp!, {r0} ldr r4, =rt_interrupt_from_thread ldr r5, [r4] str sp, [r5] ldr r6, =rt_interrupt_to_thread ldr r6, [r6] ldr sp, [r6] ldmfd sp!, {r4} msr spsr_cxsf, r4 ldmfd sp!, {r0-r12,lr,pc}^ /* Exception */ .macro push_svc_reg sub sp, sp, #17 * 4 stmia sp, {r0 - r12} mov r0, sp mrs r6, spsr str lr, [r0, #15*4] str r6, [r0, #16*4] str sp, [r0, #13*4] str lr, [r0, #14*4] .endm .align 5 .weak SVC_Handler SVC_Handler: vector_swi: push_svc_reg bl rt_hw_trap_swi b . .align 5 vector_undef: push_svc_reg bl rt_hw_trap_udef b . .align 5 vector_pabt: push_svc_reg bl rt_hw_trap_pabt b . .align 5 vector_dabt: push_svc_reg bl rt_hw_trap_dabt b . .align 5 vector_resv: push_svc_reg bl rt_hw_trap_resv b .