NASM說明書(v2.14.02)翻譯-3.4.1 數字常量

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3.4.1 數字常量

數字類型常量就是一個簡單的數字，NASM允許使用不同進制的數字。可以使用以下前綴H或X、D或T、Q或O、B和Y，分別表示十六進制（hexadecimal）、十進制(decimal)、八進制(octal)、二進制數（binary）。NASM也支持C語言風格的0x前綴來表示十六進制數，支持Borland Pascal或Motorola彙編器的風格，使用$前綴來表示十六進制數。但要注意在NASM中$有兩個功能（見3.1節），因此在表示十六進制數時，$之後要接數字而不能是字母。此外當前NASM接受前綴0h表示十六進制數，0d或0t表示十進制，0o或0q表示八進制，0b或oy表示二進制。請注意，與C語言不同單獨的前綴0不能表示八進制常量。
數字常量可以包含_來分割長數字。
以下例子，實際上會產生相同的代碼。

        mov     ax,200          ; decimal 
        mov     ax,0200         ; still decimal 
        mov     ax,0200d        ; explicitly decimal 
        mov     ax,0d200        ; also decimal 
        mov     ax,0c8h         ; hex 
        mov     ax,$0c8         ; hex again: the 0 is required 
        mov     ax,0xc8         ; hex yet again 
        mov     ax,0hc8         ; still hex 
        mov     ax,310q         ; octal 
        mov     ax,310o         ; octal again 
        mov     ax,0o310        ; octal yet again 
        mov     ax,0q310        ; octal yet again 
        mov     ax,11001000b    ; binary 
        mov     ax,1100_1000b   ; same binary constant 
        mov     ax,1100_1000y   ; same binary constant once more 
        mov     ax,0b1100_1000  ; same binary constant yet again 
        mov     ax,0y1100_1000  ; same binary constant yet again