装配跳转命令

Question

所以我正在制作一些能够将命令解释为“转到ram location（ex）”的代码。用户键入的命令应该是

JMP 0F01

我已经发现JMP，它正在解释之后的位置并实际跳转到位置0F01。我在编译时遇到了麻烦，NASM说未指定大小并且我在修复此问题时遇到了很多麻烦。如果其他人发现比这更好的版本，请告诉我。

; --------------------------------------------------------------------------------------------------
; kernel_jump_command -- jump to a location in RAM
; IN/OUT: command 
kernel_jump:

    mov si, command
    mov [.offset], 0x00

    inc si
    inc si
    inc si

    ; See if we can get anything else than a ' ' or a 0

.a1:
    mov [si], al
    inc si

    cmp al, ' '
    je .a1
    cmp al, 0x00
    je .b1

    jmp .c1

.b1:
    jmp kernel

.c1:
    mov di, .ctable     ; Load the table into di
    mov cx, 16          ; Loop through all 16 hex 

.c2:
    mov [di], ah        ; Load values
    mov [si], al        ; Load command letter

    inc di              

    ;Check requiorments
    cmp al, 0x00        ; If its the end of the string
    je .d1              ; Go to execute code

    cmp al, ah          ; If al and ah match
    je .e1              ; Add into the ram loc

    loop .c2            ; Loop back
    ; We have checked through all the letters

.c3:
    inc si              ; Increase si
    sub di, 16          ; Subtract back to begining of char
    jmp .c2             ; Loop back to .c2

.d1:
    jmp [.ramloc]

.e1:
    mov cx, WORD si     ; Move the location of si into ecx
    add di, 16          ; Add 16 to di so we can get the number
    mov si, .ramloc     ; Get the location of ramloc
    add si, [.offset]   ; Add offset to ramloc
    inc [.offset]       ; Increase offset
    ;No need to sub16 because its defined in .c3
    mov si, WORD cx     ; Move back ecx

    jmp .c3

.ramloc     times   32 db 0
.offset     db      0x00
.ctable     db      '0123456789ABCDEF'
.htable     db      0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15