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注册时间2023-2-16
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按着裸机开发第78讲，进行工程文件整理后，为什么start.s未被编译为start.o？
个人猜想：是否与VPATH有关呢？还是说start.s中可能存在语法错误但不会报错？
感觉这里的语句好像没有生效
$(BUILD_DIR)/%.o: %.s $(INCLUDES) | create_build
$(CC) -c $< -o $@ $(CFLAGS)
Makefile和start.s代码如下
ARCH ?= arm
ifeq ($(ARCH), arm)
CC = arm-none-eabi-gcc
LD = arm-none-eabi-ld
OBJCOPY = arm-none-eabi-objcopy
else
CC = gcc
endif
TARGET = interrupt
INC_DIR = include \
sources/led \
sources/key \
sources/common \
sources/irq
SRC_DIR = sources/project \
sources/led \
sources/key \
sources/common \
sources/irq
BUILD_DIR = build
#include头文件非标准库中存在的也不是在当前文件夹下的，需要将地址用-i(大写)包含
CFLAGS = $(patsubst %, -I%, $(INC_DIR))
INCLUDES = $(foreach dir, $(INC_DIR), $(wildcard $(dir)/*.h))
SOURCES_c = $(foreach dir, $(SRC_DIR), $(wildcard $(dir)/*.c))
SOURCES_s = $(foreach dir, $(SRC_DIR), $(wildcard $(dir)/*.s))
OBJECTS = $(patsubst %.c, $(BUILD_DIR)/%.o, $(notdir $(SOURCES_c)))
OBJECTS += $(patsubst %.s, $(BUILD_DIR)/%.o, $(notdir $(SOURCES_s)))
VPATH = $(SRC_DIR) #指定依赖文件的搜索目录
$(BUILD_DIR)/$(TARGET).bin:$(OBJECTS)
$(LD) -Tscript.lds $^ -o $(BUILD_DIR)/$(TARGET).elf
$(OBJCOPY) -O binary $(BUILD_DIR)/$(TARGET).elf $@
#上面定义了VPATH，所以不需要在%.c前加路径，$(INCLUDE)让目标依赖于所有头文件
#加上creat_build将先执行伪目标
$(BUILD_DIR)/%.o: %.c $(INCLUDES) | create_build
$(CC) -c $< -o $@ $(CFLAGS)
$(BUILD_DIR)/%.o: %.s $(INCLUDES) | create_build
$(CC) -c $< -o $@ $(CFLAGS)
.PHONY: clean create_build burn
clean:
rm -r $(BUILD_DIR)
create_build:
mkdir -p $(BUILD_DIR)
burn:
cp $(BUILD_DIR)/$(TARGET).bin /home/zh/bare_metal/download-tool/download_tool
cd /home/zh/bare_metal/download-tool/download_tool && ./mkimage.sh $(TARGET).bin
start.s:
/*DDR的前8K字节保留， [0x80000000-0x80001FFF] 保留为ROM区域 */
/*定义内存起始地址和大小*/
#define m_DDR_start 0x80000000
#define m_DDR_size 0x20000000
/*定义主代码区域，m_text_start将会作为中断向量表的起始地址，链接脚本中
*将该地址用作起始链接地址。
*/
#define m_text_start 0x80002000
/*定义Supervisor工作模式的栈起始地址和大小
*野火开发板标配512M字节的DDR, Supervisor工作模式的栈和IRQ工作模式的栈
*位于DDR的后2M地址，大小均为1M。
*/
#define SUP_model_stack_start 0x9FE00000
#define SUP_model_stack_size 0x00100000
/*定义IRQ工作模式的栈起始地址和大小，大小为1M*/
#define IRQ_model_stack_start 0x9FF00000
#define IRQ_model_stack_size 0x00100000
.globl light_led
.text
.align 2 //设置字节对齐
.global _start
_start:
ldr pc, =Reset_Handler /* Reset */
ldr pc, =Undefined_Handler /* Undefined instructions */
ldr pc, =SVC_Handler /* Supervisor Call */
ldr pc, =PrefAbort_Handler /* Prefetch abort */
ldr pc, =DataAbort_Handler /* Data abort */
.word 0 /* RESERVED */
ldr pc, =IRQ_Handler /* IRQ interrupt */
ldr pc, =FIQ_Handler /* FIQ interrupt */
Reset_Handler:
cpsid i /* 全局关闭中断 */
mrc p15, 0, r0, c1, c0, 0 /*读取CP15系统控制寄存器 */
bic r0, r0, #(0x1 << 12) /* 清除第12位（I位）禁用 I Cache */
bic r0, r0, #(0x1 << 2) /* 清除第 2位（C位）禁用 D Cache */
bic r0, r0, #0x2 /* 清除第 1位（A位）禁止严格对齐 */
bic r0, r0, #(0x1 << 11) /* 清除第11位（Z位）分支预测 */
bic r0, r0, #0x1 /* 清除第 0位（M位）禁用 MMU */
mcr p15, 0, r0, c1, c0, 0 /* 将修改后的值写回CP15寄存器 */
/* 定义IRQ工作模式的栈起始地址 */
cps #0x12
ldr sp, =IRQ_model_stack_start
/*定义User工作模式的栈起始地址，与Supervisor相同*/
cps #0x1F
ldr sp, =SUP_model_stack_start
/*定义Supervisor工作模式的栈起始地址，与User相同 */
cps #0x13
ldr sp, =SUP_model_stack_start
/*跳转到系统初始化函数，初始化GIC、CACHE-L1、mmu等等*/
ldr r2, =SystemInit
blx r2
/*开启全局中断*/
cpsie i
/*跳转到到 main 函数执行，*/
b main
b . /*死循环*/
Undefined_Handler:
b Undefined_Handler
.size Undefined_Handler, . - Undefined_Handler
.align 2
.arm
.weak SVC_Handler
.type SVC_Handler, %function
SVC_Handler:
ldr r0,=SVC_Handler
bx r0
.size SVC_Handler, . - SVC_Handler
.align 2
.arm
.weak PrefAbort_Handler
.type PrefAbort_Handler, %function
PrefAbort_Handler:
ldr r0,=PrefAbort_Handler
bx r0
.size PrefAbort_Handler, . - PrefAbort_Handler
.align 2
.arm
.weak DataAbort_Handler
.type DataAbort_Handler, %function
DataAbort_Handler:
ldr r0,=DataAbort_Handler
bx r0
.size DataAbort_Handler, . - DataAbort_Handler
.align 2
.arm
.weak IRQ_Handler
.type IRQ_Handler, %function
IRQ_Handler:
push {lr} /* Save return address+4 */
push {r0-r3, r12} /* Push caller save registers */
MRS r0, spsr /* Save SPRS to allow interrupt reentry */
push {r0}
MRC P15, 4, r1, C15, C0, 0 /* Get GIC base address */
ADD r1, r1, #0x2000 /* r1: GICC base address */
LDR r0, [r1, #0xC /* r0: IAR */
push {r0, r1}
CPS #0x13 /* Change to Supervisor mode to allow interrupt reentry */
push {lr} /* Save Supervisor lr */
ldr r2, =SystemIrqHandler
blx r2
POP {lr}
CPS #0x12 /* Back to IRQ mode */
POP {r0, r1}
STR r0, [r1, #0x10 /* Now IRQ handler finished: write to EOIR */
POP {r0}
MSR spsr_cxsf, r0
POP {r0-r3, r12}
POP {lr}
SUBS pc, lr, #4
.size IRQ_Handler, . - IRQ_Handler
.align 2
.arm
.weak FIQ_Handler
.type FIQ_Handler, %function
FIQ_Handler:
ldr r0,=FIQ_Handler
bx r0
.size FIQ_Handler, . - FIQ_Handler
.end
ENTRY(_start)
SECTIONS {
. = 0x80000000;
.text ALIGN(4):
{
build/start.o
*(.text)
}
.rodata ALIGN(4):
{
*(.rodata)
}
.data ALIGN(4):
{
*(.data)
}
__bss_start = .;
.bss ALIGN(4):
{
*(.bss)
*(COMMON)
}
__bss_end = .;
}
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发表于 2023-8-2 23:59:39
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