64位NASM中浮动划分后的分段故障

Question

我无法尝试获得每加仑程序的简单里程，输入浮点数，划分它们并打印结果。我还没有在NASM中使用花车，所以我不确定它是不是正确读取数字还是没有将它们分开。一旦程序划分两个数字，我就会出现分段错误。有什么想法吗？

extern printf, scanf, puts
SECTION .text
global main
main:
    push rbp
    mov rbp, rsp ; for correct debugging

    xor eax, eax

    ;welcome message
    mov rdi, welcome
    call puts

    ;prompt
    mov rdi, miles_prompt
    call puts

    ;input
    mov rdi, fmt
    movq xmm0, [miles]
    mov al, 1 ;1 float argument
    mov rax, 1 ;no other arguments...is this right?
    call scanf

    ;prompt
    mov rdi, gallons_prompt
    call puts

    ;input
    mov rdi, fmt
    movq xmm0, [gallons]
    mov al, 1
    mov rax, 1
    call scanf

    ;divide floats
    movq xmm0, [miles]
    movq xmm1, [gallons]
    divsd xmm0, xmm1

    ;print answer
    mov rdi, answer
    mov rsi, rax
    mov rax, 1
    call printf

    ;exit(0)
    mov rsp, rbp
    pop rbp
    ret


SECTION .data
    welcome: db "*** MPG Calc ***", 10, 0
    miles_prompt: db "How many miles did you travel: ", 0
    gallons_prompt: db "How many gallons of gas did you use: ", 0
    answer: db "MPG: %lf", 0
    fmt: db "%lf", 0
    miles: dq 0, 0
    gallons: dq 0, 0

这是我的终端：

$ nasm -f elf64 -s mpg.asm
$ g++ mpg.o -o ./mpg
$ ./mpg
*** MPG Calc ***

How many miles did you travel: 
6
How many gallons of gas did you use: 
4
Segmentation fault (core dumped)