汇编中的db和dw

assume cs:code
code segment
    ; db 1h,2h,3h,4h; arr[] in cs ip=[0,1,2,3]
    dw 1200h,1300h; arr[] in cs ip=[0,2,4] 读出来是反的1200变0012，很烦这个我一般都是试一下就知道了不记
    ;会读成代码
    jmp exit
    exit:
        mov ax,4c00h
        int 21h
code ends
end