#include <stdio.h>#define hi8(x)    ((( struct { unsigned char l; unsigned char h; } *)(&x))->h)
#define lo8(x)    ((( struct { unsigned char l; unsigned char h; } *)(&x))->l)
#define hi8a(x)    (((x) >> 8) & 0xff)
#define lo8a(x)    ((x) & 0xff)int main(void)
{unsigned short x;scanf("%4x", &x);                     // 不能用字面量测试, 否则-Os编译时会直接给求值了printf("%2X %2Xn", hi8(x), lo8(x));printf("%2X %2Xn", hi8a(x), lo8a(x));return 0;
}

  call    _scanflea   eax, [esp+30]movzx eax, BYTE PTR [eax]movzx    edx, allea  eax, [esp+30]movzx eax, BYTE PTR [eax+1]                   ; 这里错开1字节取值movzx   eax, almov  DWORD PTR [esp+8], edxmov  DWORD PTR [esp+4], eaxmov  DWORD PTR [esp], OFFSET FLAT:LC1      ; LC1是printf的格式字符串call    _printfmovzx    eax, WORD PTR [esp+30]movzx    eax, axmovzx    edx, almovzx    eax, WORD PTR [esp+30]shr  ax, 8                      ; 移位movzx    eax, axmovzx    eax, almov  DWORD PTR [esp+8], edxmov  DWORD PTR [esp+4], eaxmov  DWORD PTR [esp], OFFSET FLAT:LC1call    _printf

    call    _scanfmovzx eax, BYTE PTR [esp+30]mov  DWORD PTR [esp], OFFSET FLAT:LC1   ; 常量入栈提到前面了mov   DWORD PTR [esp+8], eaxmovzx    eax, BYTE PTR [esp+31]               ; 取值错开1字节mov  DWORD PTR [esp+4], eaxcall _printfmov  ax, WORD PTR [esp+30]mov   DWORD PTR [esp], OFFSET FLAT:LC1movzx   edx, almovzx    eax, ah                          ; 这次把移位优化掉了, 直接利用ax寄存器的高低位.mov DWORD PTR [esp+8], edxmov  DWORD PTR [esp+4], eaxcall _printf

   bl  scanfsub    r3, fp, #6ldrb  r3, [r3, #1]    @ zero_extendqisi2mov  r2, r3sub   r3, fp, #6ldrb  r3, [r3]    @ zero_extendqisi2           ; 错开1字节ldr    r0, .L3+4                     ; .L3+4是printf的格式字符串mov r1, r2mov   r2, r3bl    printfldrh  r3, [fp, #-6]mov    r3, r3, lsr #8mov   r3, r3, asl #16mov  r3, r3, lsr #16and  r2, r3, #255ldrh    r3, [fp, #-6]and    r3, r3, #255ldr r0, .L3+4mov   r1, r2mov   r2, r3bl    printf

 bl  scanfldrb   r1, [sp, #7]    @ zero_extendqisi2ldrb r2, [sp, #6]    @ zero_extendqisi2    ; 错开1字节mov   r0, r4                   ; .L3+4被提前放进r4了bl printfldrh  r1, [sp, #6]mov r0, r4mov   r1, r1, lsr #8             ; 移位ldrb r2, [sp, #6]    @ zero_extendqisi2bl   printf

#include <stdio.h>#define hi8(x)    ((( struct { unsigned char l; unsigned char h; } *)(&x))->h)
#define lo8(x)    ((( struct { unsigned char l; unsigned char h; } *)(&x))->l) int main(void)
{unsigned short x = 0x1234;hi8(x)--;lo8(x)++;printf("%xn", x);return 0;
}