我试图在从scanf获得3个输入后将结果输出给用户。
当我运行我的代码时，我能够得到我需要的输入。但是，在我收集输入并开始计算之后，它会崩溃。
顺便说一下，我用的是Ubuntu14.04和g++以及NASM64位。
应该是这样的：
This program is brought to you by Chris Tarazi
Welcome to Areas of Trapezoids
Please enter one of the base numbers: 5.8
Please enter the other base number: 2.2
Please enter the height: 6.5
****//Crashes here with Segmentation fault (core dumped)****
The area of a trapezoid with sizes 5.799999999999999365, 2.200000000000000153,
and 6.500000000000000000 is 26.000000000000000328
Have a nice day. Enjoy your trapezoids.
C++文件：#include <stdio.h>
#include <stdint.h>
extern "C" double ComputeArea(); // links with global in assembly
using namespace std;
int main()
{
double area;
printf("This program is brought to you by Chris Tarazi.\n");
area = ComputeArea();
printf("Have a nice day. Enjoy your trapezoids.\n");
return 0;
}
程序集文件：
extern printf ; This function will be linked later.
extern scanf
global ComputeArea ; Declare function global to link with "extern" from C++.
;---------------------------------Declare variables-------------------------------------------
segment .data
welcome: db "Welcome to the area of trapezoids.", 10, 0
input: db "Please enter one of the base numbers: ", 0
secInput: db "Please enter the other base number: ", 0
output: db "The area of a trapezoid with sizes %1.18lf, %1.18lf, and %1.18lf is %1.18lf .", 10, 0
hInput: db "Please enter the height: ", 0
inputformat: db "%lf", 0
stringformat: db "%s", 0
fourfloatformat: db "%1.18lf %1.18lf %1.18lf %1.18lf", 0
;---------------------------------Begin segment of executable code------------------------------
segment .text
ComputeArea: ; Area of trapezoid = ((a + b) / 2) * h.
push rbp ; Save a copy of the stack base pointer
mov rbp, rsp ; We do this in order to be 100% compatible with C and C++.
push rbx ; Back up rbx
push rcx ; Back up rcx
push rdx ; Back up rdx
push rsi ; Back up rsi
push rdi ; Back up rdi
push r8 ; Back up r8
push r9 ; Back up r9
push r10 ; Back up r10
push r11 ; Back up r11
push r12 ; Back up r12
push r13 ; Back up r13
push r14 ; Back up r14
push r15 ; Back up r15
pushf ; Back up rflags
;---------------------------------Output messages to user---------------------------------------
mov qword rax, 0
mov rdi, stringformat
mov rsi, welcome
call printf
mov qword rax, 0
mov rdi, stringformat
mov rsi, input
call printf
push qword 0
mov qword rax, 0
mov rdi, inputformat
mov rsi, rsp ;firstbase
call scanf
movsd xmm0, [rsp]
pop rax
mov qword rax, 0
mov rdi, stringformat
mov rsi, secInput
call printf
push qword 0
mov qword rax, 0
mov rdi, inputformat
mov rsi, rsp ;secondbase
call scanf
movsd xmm1, [rsp + 4]
pop rax
mov qword rax, 0
mov rdi, stringformat
mov rsi, hInput
call printf
push qword 0
mov qword rax, 0
mov rdi, inputformat
mov rsi, rsp ;height
call scanf
movsd xmm2, [rsp + 8]
pop rax
;---------------------------------Begin ComputeArea Calculation-----------------------------------
mov rax, 2
cvtsi2sd xmm3, rax
addsd xmm0, xmm1
divsd xmm0, xmm3
mulsd xmm0, xmm2
ret
;---------------------------------Output result to user-------------------------------------------
mov rax, 3
mov rdi, output
call printf
最佳答案
首先，你到底为什么要保存所有这些记录？!? 64位Linux的ABI表示，如果在函数中使用这些寄存器，则只需保存rbx、rbp和r12 - r15。另外，使用汇编程序时，无需在64位land中创建堆栈帧（另外，您甚至不使用rbp！为什么要创建堆栈帧？）唯一非常重要的是确保堆栈在16字节的边界上对齐—调用会推送8字节的返回地址，因此ComputeArea函数中所需的只是在ret之前sub rsp, 8和add rsp, 8。
在你的第一个scanf中，你在使用rsp而没有调整它，你只是过度保护了一些东西！
你在这里做一些计算：
mov rax, 2
cvtsi2sd xmm3, rax
addsd xmm0, xmm1
divsd xmm0, xmm3
mulsd xmm0, xmm2
ret
你从这里的程序返回，但不要弹出所有你刚才推的寄存器！！所以基本上你的堆栈指针都是乱七八糟的！CPU不知道返回地址是什么！
你在开场白中所做的，在你回来之前必须在结尾部分颠倒过来！
也许，你应该从简单开始，读3个浮动，并尝试打印它们！
当我更正您的代码时，这是我的输出：
Welcome to the area of trapezoids.
Please enter one of the base numbers: 5.8
Please enter the other base number: 2.2
Please enter the height: 6.5
The area of a trapezoid with sizes 5.799999999999999822, 2.200000000000000178, and 6.500000000000000000 is 26.000000000000000000 .
关于c++ - NASM 64bit中的段错误，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/25477787/