1 启动代码分析(for MIPS): 2 packages/hal/mips/arch/v2_0/src/vector.S 3 FUNC_START(reset_vector) //reset向量,地址为0xbfc00000,内核由此地址启动 4 5 #ifndef CYG_HAL_STARTUP_RAM 6 # if defined(CYGPKG_HAL_RESET_VECTOR_FIRST_CODE) 7 hal_reset_vector_first_code 8 # endif 9 # if defined(CYGPKG_HAL_EARLY_INIT) 10 hal_early_init 11 # endif 12 # Decide whether this is an NMI, cold or warm boot. 13 14 mfc0 k0,status # get status reg //处理NMI位,MIPS R3000中不涉及NMI操作 15 lui k1,0x0008 # isolate NMI bit 16 and k1,k1,k0 17 beqz k1,1f # skip if zero 18 nop 19 20 lar k1,__nmi_entry # jump to ROM nmi code 21 jalr k1 22 nop 23 1: 24 lui k1,0x0010 # isolate soft reset bit 25 and k1,k1,k0 26 beqz k1,2f # skip if zero 27 nop 28 29 lar k1,__warm_start # jump to ROM warm_start code //__warm_start代码用于调试,可选 30 jr k1 31 nop 32 2: 33 la k0,INITIAL_CONFIG0 # Set up config0 register //初始化config0寄存器,MIPS R3000没有这个寄存器 34 mtc0 k0,config0 # to disable cache //禁用cache 35 #endif 36 lar v0,_start # jump to start //加载_start标号地址(此处的lar指令MIPS R3000不支持) 37 #ifdef CYGARC_START_FUNC_UNCACHED 38 CYGARC_ADDRESS_REG_UNCACHED(v0) 39 #endif 40 41 jr v0 //跳转到_start处 42 nop # (delay slot) 43 44 FUNC_END(reset_vector) 45 46 FUNC_START(_start) //_start函数,做大部分初始化工作,具体代码在_start之后分析 47 48 # Initialize hardware 49 hal_cpu_init //packages/hal/mips/arch/v2_0/include/arch.inc 初始化watchdog寄存器,cause寄存器清零初始化status寄存器初始化config0寄存器(MIPS R3000没有config0寄存器) 50 hal_diag_init //诊断支持初始化,如果未定义CYGPKG_HAL_MIPS_DIAG_DEFINED,则在packages/hal/mips/arch/v2_0/include/arch.inc中定义一个空宏,如果定义了则实现依赖于特定平台,如packages/hal/mips/tx39/v2_0/src/hal_duag.c 51 hal_mmu_init //初始化mmu,如果未定义CYGPKG_HAL_MIPS_MMU_DEFINED,则表示该variant不支持mmu,则在packages/hal/mips/arch/v2_0/include/arch.inc中定义一个空宏,如果定义了则实现依赖于特定平台,如packages/hal/mips/vrc437x/v2_0/include/platform.inc 52 hal_fpu_init //packages/hal/mips/arch/v2_0/include/arch.inc,初始化fpu 53 hal_memc_init //初始化memory控制器,如果未定义CYGPKG_HAL_MIPS_MEMC_DEFINED,则表示该platform没有memory控制器,则在packages/hal/mips/arch/v2_0/include/arch.inc中定义一个空宏,如果定义了则实现依赖于特定平台,如packages/hal/mips/tx39/v2_0/include/variant.inc,该宏也可能在platform.inc中实现 54 hal_intc_init //初始化中断控制器,如果未定义CYGPKG_HAL_MIPS_INTC_INIT_DEFINED,则表示该platform没有中断控制器,则在packages/hal/mips/arch/v2_0/include/arch.inc中定义该宏,在status寄存器中禁用所有中断,如果定义了则实现依赖于特定平台,如packages/hal/mips/tx39/v2_0/include/variant.inc,该宏也可能在platform.inc中实现 55 hal_cache_init //初始化cache,如果未定义CYGPKG_HAL_MIPS_CACHE_DEFINED,则表示该variant的cache是标准cache,则在packages/hal/mips/arch/v2_0/include/arch.inc中定义该宏,使用config寄存器初始化cache,如果定义了则实现依赖于特定variant,如packages/hal/mips/tx49/v2_0/include/variant.inc 56 hal_timer_init //初始化timer,如果未定义CYGPKG_HAL_MIPS_TIMER_DEFINED,则表示该platform没有timer,则在packages/hal/mips/arch/v2_0/include/arch.inc中定义一个空宏,如果定义了则实现依赖于特定platform 57 58 #ifdef CYGARC_START_FUNC_UNCACHED 59 # switch to cached execution address if necessary 60 # assumption is that hal_cache_init makes this safe 61 lar v0,1f 62 jr v0 63 nop 64 1: 65 #endif 66 67 # Load Global Pointer register. 68 la gp,_gp //加载gp寄存器 69 70 # load initial stack pointer //设置stack指针,给c代码使用,通常interrupt stack用于此目的 71 la a0,__interrupt_stack //定义于vector.S,定义如下: 72 .balign 16 73 .global cyg_interrupt_stack 74 cyg_interrupt_stack: 75 __interrupt_stack: 76 .long 0,0,0,0,0,0,0,0 77 move sp,a0 //加载stack指针 78 79 hal_mon_init //初始化monitor,用于安装中断向量,如果未定义CYGPKG_HAL_MIPS_MON_DEFINED,则表示该platform未实现monitor,则在packages/hal/mips/arch/v2_0/include/arch.inc中定义一个空宏,如果定义了则实现依赖于特定platform,如packages/hal/mips/rm7000/v2_0/include/platform.inc,一般会调用hal_vectors_init() 80 #ifdef CYG_HAL_STARTUP_ROM //如果eCos从ROM启动,则拷贝data段到RAM中 81 # Copy data from ROM to RAM 82 83 .extern hal_copy_data 84 jal hal_copy_data //packages/hal/mips/arch/v2_0/src/hal_misc.c 85 nop 86 87 #endif 88 89 # Zero BSS //bss段清零 90 91 .extern hal_zero_bss 92 jal hal_zero_bss //packages/hal/mips/arch/v2_0/src/vectors.S 93 nop 94 95 # Call variant and platform HAL 96 # initialization routines. 97 98 .extern hal_variant_init 99 jal hal_variant_init //variant初始化,packages/hal/mips/tx39/v2_0/src/var_misc.c,大部分为空函数,也可在此处进一步初始化中断控制器,PCI桥,IO设备,启用cache等 100 nop 101 102 .extern hal_platform_init 103 jal hal_platform_init //platform初始化,packages/hal/mips/vrc437x/v2_0/src/plf_misc.c,可以不实现,也可在此处进一步初始化中断控制器,PCI桥,IO设备,启用cache等 104 nop 105 106 # Call constructors 107 .extern cyg_hal_invoke_constructors 108 jal cyg_hal_invoke_constructors //建立构造函数表,运行静态构造函数(packages/hal/mips/arch/v2_0/src/hal_misc.c) 109 nop 110 111 #if defined(CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS) //如果实现了GDB stub,则初始化 112 .extern initialize_stub 113 jal initialize_stub //初始化GDB stub,packages/hal/common/v2_0/src/generic-stub.c 114 nop 115 #endif 116 #if defined(CYGDBG_HAL_MIPS_DEBUG_GDB_CTRLC_SUPPORT) //如果GDB需要ctrl-c支持,则初始化 117 .extern hal_ctrlc_isr_init 118 jal hal_ctrlc_isr_init //初始化GDB ctrl-c支持,实现依赖于platform,如packages/hal/mips/vrc437x/v2_0/src/plf_misc.c 119 nop 120 #endif 121 # Call cyg_start 122 .extern cyg_start 123 j cyg_start //调用cyg_start()进入主循环,kernel开始运行,永不返回,cyg_start()由应用程序自己实现,可在此处调用_bsp_init()初始化设备驱动,一般实现如下: 124 void 125 cyg_start(void) 126 { 127 cyg_thread_create(10, // Priority - just a number 128 (cyg_thread_entry_t*)console_test, // entry 129 0, // 130 "console_thread", // Name 131 &stack[0], // Stack 132 STACK_SIZE, // Size 133 &thread_handle, // Handle 134 &thread_data // Thread data structure 135 ); 136 cyg_thread_resume(thread_handle); 137 cyg_scheduler_start(); 138 } 139 lui ra,0 140 141 FUNC_END(_start )
eCos学习笔记之启动代码分析
转载上一篇:VTSS Error code
下一篇:测试字体
提问和评论都可以,用心的回复会被更多人看到
评论
发布评论
相关文章
-
RHCE 学习笔记之文件系统和磁盘管理09
RHCE 学习笔记之文件系统和磁盘管理09
文件系统 ide 2d mount unmount -
Linux学习笔记之Linux启动引导过程
<!-- Article Body --> 早期时,启动一台计算机意味着要给计算机喂一条包含引导程序的纸带
linux启动引导过程 加载 linux ios -
JAVA学习笔记之SVN代码回滚
svn 代码回滚
svn 回滚 版本号 -
[笔记]机器学习之机器学习模型及案例分析《一》
环境:python3.7IDEA推导公式进行建模优化模型评估系数根据模型进行预测基于网页的用于交互计算的应用程序___还可以写C++Zotero。
机器学习 python 人工智能 损失函数 拟合