• 可以通过 register read 查看通用寄存器

  (lldb) register read
  General Purpose Registers:
           x0 = 0x000000016f316f60
           x1 = 0x0000000000000000
           x2 = 0x000000013fe05b10
           x3 = 0x0000000000000000
           x4 = 0x0000000000000000
           x5 = 0x000000016f316dc0
           x6 = 0x0000000214f04e0c  
           x7 = 0x0000000000000400
           x8 = 0x0600000223fad2bf (0x0000000223fad2bf) (void *)0x00000223fad30800
           x9 = 0x0100000000000000
          x10 = 0x0600000223fad2bf (0x0000000223fad2bf) (void *)0x00000223fad30800
          x11 = 0x0700000223fad2bf (0x0000000223fad2bf) (void *)0x00000223fad30800
          x12 = 0x000000000000000a
          x13 = 0x000000013fd06c70
          x14 = 0x0000000000000000
          x15 = 0x0000000100af5330  (void *)0x0000000100af5308: AppDelegate
          x16 = 0x00000001e33afe4c  libobjc.A.dylib`objc_storeStrong
          x17 = 0x0000000226d2a570  (void *)0x00000001e33ab100: objc_release
          x18 = 0x0000000000000000
          x19 = 0x0000000000000000
          x20 = 0x000000013fe05b10
          x21 = 0x00000002148c270c  
          x22 = 0x0000000000000001
          x23 = 0x0000000000000000
          x24 = 0x0000000000000001
          x25 = 0x0000000000000000
          x26 = 0x00000002153a91a9  
          x27 = 0x000000002b870064
          x28 = 0x0000000000000010
           fp = 0x000000016f316f80
           lr = 0xca2abd8100aedfd0 (0x0000000100aedfd0) AssemblyTutorails`-[AppDelegate application:didFinishLaunchingWithOptions:] + 76 at AppDelegate.m:18
           sp = 0x000000016f316f40
           pc = 0x0000000100aedfd8  AssemblyTutorails`-[AppDelegate application:didFinishLaunchingWithOptions:] + 84 at AppDelegate.m:22:1
         cpsr = 0x60001000
  
  (lldb) 
  

其中

• 通用寄存器

  • 64bit的: x0 - x28 (29个，每个64bit, 即8字节)
  • 32bit的: w0 - w28(属于0x - x28的低 32bit，即64bit的寄存器的一半空间低位部分)
  • x0 - x7 通常用来存放函数的参数，如果参数超出8个的数量，更多的参数使用堆栈来传递
  • x0 通常用来存放函数的返回值

• 程序计数器

  • pc （Program Counter）

• 堆栈指针

  • sp (Stack Pointer)
  • fp (Frame Pointer), 也就是 x29

• 链接寄存器

  • lr(Link Register)，也就是 x30

• 程序状态寄存器

  • cpsr(Current Program Status Register)
  • spsr(Saved Program Status Register) 异常状况下使用