• 汇编代码 分析实践 分析指定内存地址的信息


    t_assembly.c

    #include <stdio.h>
    int f()
    {
    	char sa[] = "a";
    	char sz[] = "z";
    	char hi[] = "hi";
    	int i = 6;
    	int j = 10;
    	unsigned k = 10;
    	int ii = -6;
    	int jj = -10;
    	int n = -110;
    	printf("hi");
    	return 0;
    }
    int main()
    {
    	int im = 6;
    	int jm = 10;
    	unsigned k = 10;
    	while (1 == 1)
    	{
    		f();
    	}
    	return 0;
    }
    

      

    gcc -g t_assembly.c

    ./a.out

    perf record -a

    perf report --pid=104168

    Samples: 569K of event 'cpu-clock', 4000 Hz, Event count (approx.): 142343250000
    
    Percent│                                                                                                                                                          ◆
           │    /root/.debug/.build-id/e9/861963f99551d49974e36550e73ccc2c63480f/elf:     文件格式 elf64-x86-64                                                      ▒
           │                                                                                                                                                          ▒
           │                                                                                                                                                          ▒
           │    Disassembly of section .text:                                                                                                                         ▒
           │                                                                                                                                                          ▒
           │    000000000040052d <f>:                                                                                                                                 ▒
           │    f():                                                                                                                                                  ▒
           │    #include <stdio.h>                                                                                                                                    ▒
           │    int f()                                                                                                                                               ▒
           │    {                                                                                                                                                     ▒
      8.56 │      push   %rbp                                                                                                                                         ▒
      2.84 │      mov    %rsp,%rbp                                                                                                                                    ▒
      0.80 │      sub    $0x40,%rsp                                                                                                                                   ▒
           │            char sa[] = "a";                                                                                                                              ▒
      6.13 │      movw   $0x61,-0x20(%rbp)                                                                                                                            ▒
           │            char sz[] = "z";                                                                                                                              ▒
     18.07 │      movw   $0x7a,-0x30(%rbp)                                                                                                                            ▒
           │            char hi[] = "hi";                                                                                                                             ▒
      6.39 │      movw   $0x6968,-0x40(%rbp)                                                                                                                          ▒
      5.19 │      movb   $0x0,-0x3e(%rbp)                                                                                                                             ▒
           │            int i = 6;                                                                                                                                    ▒
      3.98 │      movl   $0x6,-0x4(%rbp)                                                                                                                              ▒
           │            int j = 10;                                                                                                                                   ▒
      5.28 │      movl   $0xa,-0x8(%rbp)                                                                                                                              ▒
           │            unsigned k = 10;                                                                                                                              ▒
      5.59 │      movl   $0xa,-0xc(%rbp)                                                                                                                              ▒
           │            int ii = -6;                                                                                                                                  ▒
      2.84 │      movl   $0xfffffffa,-0x10(%rbp)                                                                                                                      ▒
           │            int jj = -10;                                                                                                                                 ▒
      4.41 │      movl   $0xfffffff6,-0x14(%rbp)                                                                                                                      ▒
           │            int n = -110;                                                                                                                                 ▒
      4.44 │      movl   $0xffffff92,-0x18(%rbp)                                                                                                                      ▒
           │            printf("hi");                                                                                                                                 ▒
      3.20 │      mov    $0x400650,%edi                                                                                                                               ▒
      0.23 │      mov    $0x0,%eax                                                                                                                                    ▒
      1.26 │    → callq  printf@plt                                                                                                                                   ▒
           │            return 0;                                                                                                                                     ▒
     10.59 │      mov    $0x0,%eax                                                                                                                                    ▒
           │    }                                                                                                                                                     ▒
      0.72 │      leaveq                                                                                                                                              ▒
      9.48 │    ← retq                                                                                                                                                ▒
                                          
    

     问题:解释 0x400650信息

    Samples: 569K of event 'cpu-clock', 4000 Hz, Event count (approx.): 142343250000
    main  /home/hdp/workbench/perfUcan/a.out [Percent: local period]
    Percent│                                                                                                                                                          ◆
           │    /root/.debug/.build-id/e9/861963f99551d49974e36550e73ccc2c63480f/elf:     文件格式 elf64-x86-64                                                      ▒
           │                                                                                                                                                          ▒
           │                                                                                                                                                          ▒
           │    Disassembly of section .text:                                                                                                                         ▒
           │                                                                                                                                                          ▒
           │    000000000040058b <main>:                                                                                                                              ▒
           │    main():                                                                                                                                               ▒
           │            int n = -110;                                                                                                                                 ▒
           │            printf("hi");                                                                                                                                 ▒
           │            return 0;                                                                                                                                     ▒
           │    }                                                                                                                                                     ▒
           │    int main()                                                                                                                                            ▒
           │    {                                                                                                                                                     ▒
           │      push   %rbp                                                                                                                                         ▒
           │      mov    %rsp,%rbp                                                                                                                                    ▒
           │      sub    $0x10,%rsp                                                                                                                                   ▒
           │            int im = 6;                                                                                                                                   ▒
           │      movl   $0x6,-0x4(%rbp)                                                                                                                              ▒
           │            int jm = 10;                                                                                                                                  ▒
           │      movl   $0xa,-0x8(%rbp)                                                                                                                              ▒
           │            unsigned k = 10;                                                                                                                              ▒
           │      movl   $0xa,-0xc(%rbp)                                                                                                                              ▒
           │            while (1 == 1)                                                                                                                                ▒
           │            {                                                                                                                                             ▒
           │                    f();                                                                                                                                  ▒
     53.47 │1d:   mov    $0x0,%eax                                                                                                                                    ▒
      1.34 │    → callq  f                                                                                                                                            ▒
           │            }                                                                                                                                             ▒
     45.19 │    ↑ jmp    1d                                                                                                                                           ▒
                                                                                                                                                                      ▒
                                                                                                                                                                      ▒
                                      
    

      

    readelf -all a.out

    [hdp@cmd perfUcan]$ readelf -all a.out
    ELF 头:
      Magic:  7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
      类别:                              ELF64
      数据:                              2 补码,小端序 (little endian)
      版本:                              1 (current)
      OS/ABI:                            UNIX - System V
      ABI 版本:                          0
      类型:                              EXEC (可执行文件)
      系统架构:                          Advanced Micro Devices X86-64
      版本:                              0x1
      入口点地址:              0x400440
      程序头起点:              64 (bytes into file)
      Start of section headers:          7472 (bytes into file)
      标志:             0x0
      本头的大小:       64 (字节)
      程序头大小:       56 (字节)
      Number of program headers:         9
      节头大小:         64 (字节)
      节头数量:         35
      字符串表索引节头: 34
    
    节头:
      [号] 名称              类型             地址              偏移量
           大小              全体大小          旗标   链接   信息   对齐
      [ 0]                   NULL             0000000000000000  00000000
           0000000000000000  0000000000000000           0     0     0
      [ 1] .interp           PROGBITS         0000000000400238  00000238
           000000000000001c  0000000000000000   A       0     0     1
      [ 2] .note.ABI-tag     NOTE             0000000000400254  00000254
           0000000000000020  0000000000000000   A       0     0     4
      [ 3] .note.gnu.build-i NOTE             0000000000400274  00000274
           0000000000000024  0000000000000000   A       0     0     4
      [ 4] .gnu.hash         GNU_HASH         0000000000400298  00000298
           000000000000001c  0000000000000000   A       5     0     8
      [ 5] .dynsym           DYNSYM           00000000004002b8  000002b8
           0000000000000060  0000000000000018   A       6     1     8
      [ 6] .dynstr           STRTAB           0000000000400318  00000318
           000000000000003f  0000000000000000   A       0     0     1
      [ 7] .gnu.version      VERSYM           0000000000400358  00000358
           0000000000000008  0000000000000002   A       5     0     2
      [ 8] .gnu.version_r    VERNEED          0000000000400360  00000360
           0000000000000020  0000000000000000   A       6     1     8
      [ 9] .rela.dyn         RELA             0000000000400380  00000380
           0000000000000018  0000000000000018   A       5     0     8
      [10] .rela.plt         RELA             0000000000400398  00000398
           0000000000000048  0000000000000018  AI       5    23     8
      [11] .init             PROGBITS         00000000004003e0  000003e0
           000000000000001a  0000000000000000  AX       0     0     4
      [12] .plt              PROGBITS         0000000000400400  00000400
           0000000000000040  0000000000000010  AX       0     0     16
      [13] .text             PROGBITS         0000000000400440  00000440
           00000000000001f2  0000000000000000  AX       0     0     16
      [14] .fini             PROGBITS         0000000000400634  00000634
           0000000000000009  0000000000000000  AX       0     0     4
      [15] .rodata           PROGBITS         0000000000400640  00000640
           0000000000000013  0000000000000000   A       0     0     8
      [16] .eh_frame_hdr     PROGBITS         0000000000400654  00000654
           000000000000003c  0000000000000000   A       0     0     4
      [17] .eh_frame         PROGBITS         0000000000400690  00000690
           0000000000000114  0000000000000000   A       0     0     8
      [18] .init_array       INIT_ARRAY       0000000000600e10  00000e10
           0000000000000008  0000000000000008  WA       0     0     8
      [19] .fini_array       FINI_ARRAY       0000000000600e18  00000e18
           0000000000000008  0000000000000008  WA       0     0     8
      [20] .jcr              PROGBITS         0000000000600e20  00000e20
           0000000000000008  0000000000000000  WA       0     0     8
      [21] .dynamic          DYNAMIC          0000000000600e28  00000e28
           00000000000001d0  0000000000000010  WA       6     0     8
      [22] .got              PROGBITS         0000000000600ff8  00000ff8
           0000000000000008  0000000000000008  WA       0     0     8
      [23] .got.plt          PROGBITS         0000000000601000  00001000
           0000000000000030  0000000000000008  WA       0     0     8
      [24] .data             PROGBITS         0000000000601030  00001030
           0000000000000004  0000000000000000  WA       0     0     1
      [25] .bss              NOBITS           0000000000601034  00001034
           0000000000000004  0000000000000000  WA       0     0     1
      [26] .comment          PROGBITS         0000000000000000  00001034
           000000000000002d  0000000000000001  MS       0     0     1
      [27] .debug_aranges    PROGBITS         0000000000000000  00001061
           0000000000000030  0000000000000000           0     0     1
      [28] .debug_info       PROGBITS         0000000000000000  00001091
           000000000000016a  0000000000000000           0     0     1
      [29] .debug_abbrev     PROGBITS         0000000000000000  000011fb
           000000000000007d  0000000000000000           0     0     1
      [30] .debug_line       PROGBITS         0000000000000000  00001278
           0000000000000058  0000000000000000           0     0     1
      [31] .debug_str        PROGBITS         0000000000000000  000012d0
           00000000000000c6  0000000000000001  MS       0     0     1
      [32] .symtab           SYMTAB           0000000000000000  00001398
           0000000000000678  0000000000000018          33    51     8
      [33] .strtab           STRTAB           0000000000000000  00001a10
           00000000000001d3  0000000000000000           0     0     1
      [34] .shstrtab         STRTAB           0000000000000000  00001be3
           0000000000000148  0000000000000000           0     0     1
    Key to Flags:
      W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
      L (link order), O (extra OS processing required), G (group), T (TLS),
      C (compressed), x (unknown), o (OS specific), E (exclude),
      l (large), p (processor specific)
    
    There are no section groups in this file.
    
    程序头:
      Type           Offset             VirtAddr           PhysAddr
                     FileSiz            MemSiz              Flags  Align
      PHDR           0x0000000000000040 0x0000000000400040 0x0000000000400040
                     0x00000000000001f8 0x00000000000001f8  R E    8
      INTERP         0x0000000000000238 0x0000000000400238 0x0000000000400238
                     0x000000000000001c 0x000000000000001c  R      1
          [Requesting program interpreter: /lib64/ld-linux-x86-64.so.2]
      LOAD           0x0000000000000000 0x0000000000400000 0x0000000000400000
                     0x00000000000007a4 0x00000000000007a4  R E    200000
      LOAD           0x0000000000000e10 0x0000000000600e10 0x0000000000600e10
                     0x0000000000000224 0x0000000000000228  RW     200000
      DYNAMIC        0x0000000000000e28 0x0000000000600e28 0x0000000000600e28
                     0x00000000000001d0 0x00000000000001d0  RW     8
      NOTE           0x0000000000000254 0x0000000000400254 0x0000000000400254
                     0x0000000000000044 0x0000000000000044  R      4
      GNU_EH_FRAME   0x0000000000000654 0x0000000000400654 0x0000000000400654
                     0x000000000000003c 0x000000000000003c  R      4
      GNU_STACK      0x0000000000000000 0x0000000000000000 0x0000000000000000
                     0x0000000000000000 0x0000000000000000  RW     10
      GNU_RELRO      0x0000000000000e10 0x0000000000600e10 0x0000000000600e10
                     0x00000000000001f0 0x00000000000001f0  R      1
    
     Section to Segment mapping:
      段节...
       00
       01     .interp
       02     .interp .note.ABI-tag .note.gnu.build-id .gnu.hash .dynsym .dynstr .gnu.version .gnu.version_r .rela.dyn .rela.plt .init .plt .text .fini .rodata .eh_frame_hdr .eh_frame
       03     .init_array .fini_array .jcr .dynamic .got .got.plt .data .bss
       04     .dynamic
       05     .note.ABI-tag .note.gnu.build-id
       06     .eh_frame_hdr
       07
       08     .init_array .fini_array .jcr .dynamic .got
    
    Dynamic section at offset 0xe28 contains 24 entries:
      标记        类型                         名称/值
     0x0000000000000001 (NEEDED)             共享库:[libc.so.6]
     0x000000000000000c (INIT)               0x4003e0
     0x000000000000000d (FINI)               0x400634
     0x0000000000000019 (INIT_ARRAY)         0x600e10
     0x000000000000001b (INIT_ARRAYSZ)       8 (bytes)
     0x000000000000001a (FINI_ARRAY)         0x600e18
     0x000000000000001c (FINI_ARRAYSZ)       8 (bytes)
     0x000000006ffffef5 (GNU_HASH)           0x400298
     0x0000000000000005 (STRTAB)             0x400318
     0x0000000000000006 (SYMTAB)             0x4002b8
     0x000000000000000a (STRSZ)              63 (bytes)
     0x000000000000000b (SYMENT)             24 (bytes)
     0x0000000000000015 (DEBUG)              0x0
     0x0000000000000003 (PLTGOT)             0x601000
     0x0000000000000002 (PLTRELSZ)           72 (bytes)
     0x0000000000000014 (PLTREL)             RELA
     0x0000000000000017 (JMPREL)             0x400398
     0x0000000000000007 (RELA)               0x400380
     0x0000000000000008 (RELASZ)             24 (bytes)
     0x0000000000000009 (RELAENT)            24 (bytes)
     0x000000006ffffffe (VERNEED)            0x400360
     0x000000006fffffff (VERNEEDNUM)         1
     0x000000006ffffff0 (VERSYM)             0x400358
     0x0000000000000000 (NULL)               0x0
    
    重定位节 '.rela.dyn' 位于偏移量 0x380 含有 1 个条目:
      偏移量          信息           类型           符号值        符号名称 + 加数
    000000600ff8  000300000006 R_X86_64_GLOB_DAT 0000000000000000 __gmon_start__ + 0
    
    重定位节 '.rela.plt' 位于偏移量 0x398 含有 3 个条目:
      偏移量          信息           类型           符号值        符号名称 + 加数
    000000601018  000100000007 R_X86_64_JUMP_SLO 0000000000000000 printf@GLIBC_2.2.5 + 0
    000000601020  000200000007 R_X86_64_JUMP_SLO 0000000000000000 __libc_start_main@GLIBC_2.2.5 + 0
    000000601028  000300000007 R_X86_64_JUMP_SLO 0000000000000000 __gmon_start__ + 0
    
    The decoding of unwind sections for machine type Advanced Micro Devices X86-64 is not currently supported.
    
    Symbol table '.dynsym' contains 4 entries:
       Num:    Value          Size Type    Bind   Vis      Ndx Name
         0: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT  UND
         1: 0000000000000000     0 FUNC    GLOBAL DEFAULT  UND printf@GLIBC_2.2.5 (2)
         2: 0000000000000000     0 FUNC    GLOBAL DEFAULT  UND __libc_start_main@GLIBC_2.2.5 (2)
         3: 0000000000000000     0 NOTYPE  WEAK   DEFAULT  UND __gmon_start__
    
    Symbol table '.symtab' contains 69 entries:
       Num:    Value          Size Type    Bind   Vis      Ndx Name
         0: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT  UND
         1: 0000000000400238     0 SECTION LOCAL  DEFAULT    1
         2: 0000000000400254     0 SECTION LOCAL  DEFAULT    2
         3: 0000000000400274     0 SECTION LOCAL  DEFAULT    3
         4: 0000000000400298     0 SECTION LOCAL  DEFAULT    4
         5: 00000000004002b8     0 SECTION LOCAL  DEFAULT    5
         6: 0000000000400318     0 SECTION LOCAL  DEFAULT    6
         7: 0000000000400358     0 SECTION LOCAL  DEFAULT    7
         8: 0000000000400360     0 SECTION LOCAL  DEFAULT    8
         9: 0000000000400380     0 SECTION LOCAL  DEFAULT    9
        10: 0000000000400398     0 SECTION LOCAL  DEFAULT   10
        11: 00000000004003e0     0 SECTION LOCAL  DEFAULT   11
        12: 0000000000400400     0 SECTION LOCAL  DEFAULT   12
        13: 0000000000400440     0 SECTION LOCAL  DEFAULT   13
        14: 0000000000400634     0 SECTION LOCAL  DEFAULT   14
        15: 0000000000400640     0 SECTION LOCAL  DEFAULT   15
        16: 0000000000400654     0 SECTION LOCAL  DEFAULT   16
        17: 0000000000400690     0 SECTION LOCAL  DEFAULT   17
        18: 0000000000600e10     0 SECTION LOCAL  DEFAULT   18
        19: 0000000000600e18     0 SECTION LOCAL  DEFAULT   19
        20: 0000000000600e20     0 SECTION LOCAL  DEFAULT   20
        21: 0000000000600e28     0 SECTION LOCAL  DEFAULT   21
        22: 0000000000600ff8     0 SECTION LOCAL  DEFAULT   22
        23: 0000000000601000     0 SECTION LOCAL  DEFAULT   23
        24: 0000000000601030     0 SECTION LOCAL  DEFAULT   24
        25: 0000000000601034     0 SECTION LOCAL  DEFAULT   25
        26: 0000000000000000     0 SECTION LOCAL  DEFAULT   26
        27: 0000000000000000     0 SECTION LOCAL  DEFAULT   27
        28: 0000000000000000     0 SECTION LOCAL  DEFAULT   28
        29: 0000000000000000     0 SECTION LOCAL  DEFAULT   29
        30: 0000000000000000     0 SECTION LOCAL  DEFAULT   30
        31: 0000000000000000     0 SECTION LOCAL  DEFAULT   31
        32: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS crtstuff.c
        33: 0000000000600e20     0 OBJECT  LOCAL  DEFAULT   20 __JCR_LIST__
        34: 0000000000400470     0 FUNC    LOCAL  DEFAULT   13 deregister_tm_clones
        35: 00000000004004a0     0 FUNC    LOCAL  DEFAULT   13 register_tm_clones
        36: 00000000004004e0     0 FUNC    LOCAL  DEFAULT   13 __do_global_dtors_aux
        37: 0000000000601034     1 OBJECT  LOCAL  DEFAULT   25 completed.6355
        38: 0000000000600e18     0 OBJECT  LOCAL  DEFAULT   19 __do_global_dtors_aux_fin
        39: 0000000000400500     0 FUNC    LOCAL  DEFAULT   13 frame_dummy
        40: 0000000000600e10     0 OBJECT  LOCAL  DEFAULT   18 __frame_dummy_init_array_
        41: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS t_assembly.c
        42: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS crtstuff.c
        43: 00000000004007a0     0 OBJECT  LOCAL  DEFAULT   17 __FRAME_END__
        44: 0000000000600e20     0 OBJECT  LOCAL  DEFAULT   20 __JCR_END__
        45: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS
        46: 0000000000600e18     0 NOTYPE  LOCAL  DEFAULT   18 __init_array_end
        47: 0000000000600e28     0 OBJECT  LOCAL  DEFAULT   21 _DYNAMIC
        48: 0000000000600e10     0 NOTYPE  LOCAL  DEFAULT   18 __init_array_start
        49: 0000000000400654     0 NOTYPE  LOCAL  DEFAULT   16 __GNU_EH_FRAME_HDR
        50: 0000000000601000     0 OBJECT  LOCAL  DEFAULT   23 _GLOBAL_OFFSET_TABLE_
        51: 0000000000400630     2 FUNC    GLOBAL DEFAULT   13 __libc_csu_fini
        52: 0000000000601030     0 NOTYPE  WEAK   DEFAULT   24 data_start
        53: 0000000000601034     0 NOTYPE  GLOBAL DEFAULT   24 _edata
        54: 0000000000400634     0 FUNC    GLOBAL DEFAULT   14 _fini
        55: 000000000040052d    94 FUNC    GLOBAL DEFAULT   13 f
        56: 0000000000000000     0 FUNC    GLOBAL DEFAULT  UND printf@@GLIBC_2.2.5
        57: 0000000000000000     0 FUNC    GLOBAL DEFAULT  UND __libc_start_main@@GLIBC_
        58: 0000000000601030     0 NOTYPE  GLOBAL DEFAULT   24 __data_start
        59: 0000000000000000     0 NOTYPE  WEAK   DEFAULT  UND __gmon_start__
        60: 0000000000400648     0 OBJECT  GLOBAL HIDDEN    15 __dso_handle
        61: 0000000000400640     4 OBJECT  GLOBAL DEFAULT   15 _IO_stdin_used
        62: 00000000004005c0   101 FUNC    GLOBAL DEFAULT   13 __libc_csu_init
        63: 0000000000601038     0 NOTYPE  GLOBAL DEFAULT   25 _end
        64: 0000000000400440     0 FUNC    GLOBAL DEFAULT   13 _start
        65: 0000000000601034     0 NOTYPE  GLOBAL DEFAULT   25 __bss_start
        66: 000000000040058b    41 FUNC    GLOBAL DEFAULT   13 main
        67: 0000000000601038     0 OBJECT  GLOBAL HIDDEN    24 __TMC_END__
        68: 00000000004003e0     0 FUNC    GLOBAL DEFAULT   11 _init
    
    Version symbols section '.gnu.version' contains 4 entries:
     地址:0000000000400358  Offset: 0x000358  Link: 5 (.dynsym)
      000:   0 (*本地*)       2 (GLIBC_2.2.5)   2 (GLIBC_2.2.5)   0 (*本地*)
    
    Version needs section '.gnu.version_r' contains 1 entries:
     地址:0x0000000000400360  Offset: 0x000360  Link: 6 (.dynstr)
      000000: 版本: 1  文件:libc.so.6  计数:1
      0x0010:名称:GLIBC_2.2.5  标志:无  版本:2
    
    Displaying notes found at file offset 0x00000254 with length 0x00000020:
      所有者             Data size  Description
      GNU                  0x00000010       NT_GNU_ABI_TAG (ABI version tag)
        OS: Linux, ABI: 2.6.32
    
    Displaying notes found at file offset 0x00000274 with length 0x00000024:
      所有者             Data size  Description
      GNU                  0x00000014       NT_GNU_BUILD_ID (unique build ID bitstring)
        Build ID: e9861963f99551d49974e36550e73ccc2c63480f
    [hdp@cmd perfUcan]$
    

      

    f、main的地址都已经匹配到

     gdb attach 104168 查堆栈信息  x查内存地址信息

    (gdb) backtrace
    #0  0x00007f32fee0b9b0 in __write_nocancel () from /lib64/libc.so.6
    #1  0x00007f32fed96213 in _IO_new_file_write () from /lib64/libc.so.6
    #2  0x00007f32fed97a2e in __GI__IO_do_write () from /lib64/libc.so.6
    #3  0x00007f32fed96970 in __GI__IO_file_xsputn () from /lib64/libc.so.6
    #4  0x00007f32fed646b7 in vfprintf () from /lib64/libc.so.6
    #5  0x00007f32fed6f459 in printf () from /lib64/libc.so.6
    #6  0x0000000000400584 in f () at t_assembly.c:13
    #7  0x00000000004005b2 in main () at t_assembly.c:23
    (gdb) x/3uh 0x400650
    0x400650:       26984   0       6913
    (gdb) x/3ub 0x400650
    0x400650:       104     105     0
    (gdb) x/16ub 0x400650
    0x400650:       104     105     0       0       1       27      3       59
    0x400658:       56      0       0       0       6       0       0       0
    (gdb) x/16xb 0x400650
    0x400650:       0x68    0x69    0x00    0x00    0x01    0x1b    0x03    0x3b
    0x400658:       0x38    0x00    0x00    0x00    0x06    0x00    0x00    0x00
    

      

    二进制 十进制 十六进制 缩写 Unicode
    表示法 脱出字符
    表示法 名称/意义
    0000 0000 0 00 NUL ␀ ^@ 空字符(Null)
    0000 0001 1 01 SOH ␁ ^A 标题开始
    0000 0010 2 02 STX ␂ ^B 本文开始
    0000 0011 3 03 ETX ␃ ^C 本文结束

    001 1011 27 1B ESC ␛ ^[ 退出键


    0011 1011 59 3B ;
    二进制 十进制 十六进制 图形
    0110 0000 96 60 `
    0110 0001 97 61 a
    0110 0010 98 62 b
    0110 0011 99 63 c
    0110 0100 100 64 d
    0110 0101 101 65 e
    0110 0110 102 66 f
    0110 0111 103 67 g
    0110 1000 104 68 h
    0110 1001 105 69 i
    0110 1010 106 6A j

    将h i  赋值给edi




    https://zhuanlan.zhihu.com/p/55896356
    函数的第一行涉及rbp和rsp;这些是专用寄存器。
    rbp是指向当前栈桢底部的基指针,rsp是指向当前栈桢顶部的堆栈指针。
    (译者注:在很多翻译过来的书上,有些地方将Stack翻译为栈桢,有的地方叫堆栈,
    只要知道这里的堆栈是指Stack,Heap没关系就好)

    rbp = memory address of the base of the prev stack frame
    rsp = memory address of the top of the stack

    指针寄存器
    SP(stack pointer)
    BP(base pointer)

    堆栈的内存地址越来越低,即向地址小的地方增长。

    基指针或帧指针。它指向当前运行的函数的栈桢中的一个固定位置,并为访问函数参数和本地变量提供一个稳定的参考点(基)


    {
    MOV 指令将源操作数复制到目的操作数。作为数据传送(data transfer)指令,它几乎用在所有程序中。在它的基本格式中,第一个操作数是目的操作数,第二个操作数是源操作数:
    MOV destination,source

    其中,目的操作数的内容会发生改变,而源操作数不会改变。这种数据从右到左的移动与 C++ 或 Java 中的赋值语句相似:
    dest = source;

    在几乎所有的汇编语言指令中,左边的操作数是目标操作数,而右边的操作数是源操作数。只要按照如下原则,MOV 指令使用操作数是非常灵活的。
    两个操作数必须是同样的大小。
    两个操作数不能同时为内存操作数。
    指令指针寄存器(IP、EIP 或 RIP)不能作为目标操作数。
    }



    https://www.oschina.net/translate/the-art-of-picking-intel-registers?lang=chs&p=1
    EAX - 累加器寄存器
    EBX - 基础寄存器
    ECX - 计数器寄存器
    EDX - 数据寄存器
    ESI - 源指针
    EDI - 目的地指针
    EBP - 基本指针
    ESP - 堆栈指针

    EAX - Accumulator Register
    EBX - Base Register
    ECX - Counter Register
    EDX - Data Register
    ESI - Source Index
    EDI - Destination Index
    EBP - Base Pointer
    ESP - Stack Pointer

    在CPU中,有八个通用寄存器

    ax (add,代表相加,累加的意思)累加寄存器

    bx (base,代表基地址,存放地址的寄存器) 基址寄存器

    cx (count,个数,代表统计的意思)计数寄存器

    dx (data,数据) 数据寄存器

    SI (source) 源寄存器,存放源地址的内容的寄存器

    DI (Dest) 目标寄存器,从源寄存器中memcpy到目标寄存器中

    BP (base Point) 堆栈,理解为栈底指针,每次在栈中移动数据,出栈进栈,都会更新.记录的是当前的栈底

    SP () 堆栈栈顶指针.

    16位汇编第一讲简介
    https://www.cnblogs.com/iBinary/p/7446164.html
    32位汇编第一讲x86和8086的区别,以及OllyDbg调试器的使用
    https://www.cnblogs.com/iBinary/p/7508144.html
    一丶32位(x86也称为80386)与8086(16位)汇编的区别
    1.寄存器的改变
      AX 变为 EAX 可以这样想,16位通用寄存器前边都加个E开头

    例如:

      

    EAX EBX ECX EDX ESI EDI ESP EBP ;八个寄存器
    EIP EFLAGES ;特殊寄存器
    CS ES SS DS GS FS            ;其中GS FS是新增加的寄存器,这些段寄存器,并不是4个字节(32位的)还是以前16位的
    注意在32位下没有分段的概念的,因为寻址能力是 0- FFFFFFFF ,在当时的inter认为当初的4G已经很厉害了,那是后最好的内存才1G,放到现在看

    我们感觉4G不够用了,但也是近几年才开始用的8G

    有分区的概念,比如我们16位汇编中,给代码分段的时候,顺便分了一下区,分区是为了更好的管理代码的编写


    https://sourceware.org/gdb/current/onlinedocs/gdb/Memory.html
    u10进制 x16
    (gdb) x/16ub 0x400650
    0x400650: 104 105 0 0 1 27 3 59
    0x400658: 56 0 0 0 6 0 0 0
    (gdb) x/16xb 0x400650
    0x400650: 0x68 0x69 0x00 0x00 0x01 0x1b 0x03 0x3b
    0x400658: 0x38 0x00 0x00 0x00 0x06 0x00 0x00 0x00

    环境信息

    [hdp@cmd ~]$ cat  /proc/version
    Linux version 3.10.0-1062.4.1.el7.x86_64 (mockbuild@kbuilder.bsys.centos.org) (gcc version 4.8.5 20150623 (Red Hat 4.8.5-39) (GCC) ) #1 SMP Fri Oct 18 17:15:30 UTC 2019
    [hdp@cmd ~]$ cat /proc/cpuinfo
    processor       : 0
    vendor_id       : GenuineIntel
    cpu family      : 6
    model           : 79
    model name      : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz
    stepping        : 1
    microcode       : 0xffffffff
    cpu MHz         : 2095.146
    cache size      : 20480 KB
    physical id     : 0
    siblings        : 2
    core id         : 0
    cpu cores       : 1
    apicid          : 0
    initial apicid  : 0
    fpu             : yes
    fpu_exception   : yes
    cpuid level     : 20
    wp              : yes
    flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc rep_good nopl xtopology eagerfpu pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 movbe popcnt aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch invpcid_single ibrs ibpb stibp fsgsbase bmi1 hle avx2 smep bmi2 erms invpcid rtm rdseed adx smap xsaveopt spec_ctrl intel_stibp arch_capabilities
    bogomips        : 4190.29
    clflush size    : 64
    cache_alignment : 64
    address sizes   : 44 bits physical, 48 bits virtual
    power management:
    
    processor       : 1
    vendor_id       : GenuineIntel
    cpu family      : 6
    model           : 79
    model name      : Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz
    stepping        : 1
    microcode       : 0xffffffff
    cpu MHz         : 2095.146
    cache size      : 20480 KB
    physical id     : 0
    siblings        : 2
    core id         : 0
    cpu cores       : 1
    apicid          : 1
    initial apicid  : 1
    fpu             : yes
    fpu_exception   : yes
    cpuid level     : 20
    wp              : yes
    flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc rep_good nopl xtopology eagerfpu pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 movbe popcnt aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnowprefetch invpcid_single ibrs ibpb stibp fsgsbase bmi1 hle avx2 smep bmi2 erms invpcid rtm rdseed adx smap xsaveopt spec_ctrl intel_stibp arch_capabilities
    bogomips        : 4190.29
    clflush size    : 64
    cache_alignment : 64
    address sizes   : 44 bits physical, 48 bits virtual
    power management:
    
    [hdp@cmd ~]$
    

      

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  • 原文地址:https://www.cnblogs.com/rsapaper/p/9826439.html
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