在函数和主干上运行相同命令的不同结果 - x86-64 toy_kernel

Question

我正在编写自己的内核（目前为 32 位），如果我在 main 上运行，命令就可以工作，但是当在不同的函数上运行时，它的行为会有所不同。知道如何以及为什么吗？编辑：问题在于其他函数内的指针不起作用。

int foo(const char *str)
{   
    *(char*)0xb8000 = *str; // clears the screen probably because of 0 padding at the end
}
extern void main() {
    const char str[4] = {'A', 'B', 'C', '\0'};
     *(char*)0xb8000 = *str; // works good
    for(int i=0;i<1000000000;i++); // for delay
    foo(str);
    for(;;);
    return;
}

我期望它表现相同，但事实并非如此

启动代码在这里

[org 0x7c00]
KERNEL_LOCATION equ 0x1000

mov [boot_disk], dl

; set up stack
xor ax, ax                          
mov es, ax
mov ds, ax
mov bp, 0x8000
mov sp, bp


// GDT loading to memory and other stuff


[bits 32]
start_protected_mode:
    mov ax, DATA_SEG
    mov ds, ax
    mov ss, ax
    mov es, ax
    mov fs, ax
    mov gs, ax
    
    mov ebp, 0x90000        ; 32 bit stack base pointer
    mov esp, ebp

    jmp KERNEL_LOCATION


times 510-($-$$) db 0
dw 0xaa55

生成文件

all:
x86_64-elf-gcc -Wall -nostdlib -ffreestanding -m64 -g -c "kernel.c" -o "kernel.o"
x86_64-elf-gcc -Wall -nostdlib -ffreestanding -m64 -g -c "idt.c" -o "idt.o"
x86_64-elf-gcc -Wall -nostdlib -ffreestanding -m64 -g -c "system.c" -o "system.o"
nasm "kernel_enrty.asm" -f elf64 -o "kernel_entry.o"
nasm "start.asm" -f elf64 -o "start.o"
x86_64-elf-ld -nostdlib -o "full_kernel.bin" -Ttext 0x1000 "kernel_entry.o" "start.o" "idt.o" "system.o"  "kernel.o" -j .text --oformat binary
nasm "boot.asm" -f bin -o "boot.bin"
cat "boot.bin" "full_kernel.bin" > "everything.bin"
nasm "padding.asm" -f bin -o "padding.bin"
cat "everything.bin" "padding.bin" > "OS.bin"

Answer 1

问题是我将 32 位代码编译为 64 位

更新后的make文件：

all:
x86_64-elf-gcc -Wall -nostdlib -ffreestanding -m32 -g -c "kernel.c" -o "kernel.o"
x86_64-elf-gcc -Wall -nostdlib -ffreestanding -m32 -g -c "idt.c" -o "idt.o"
x86_64-elf-gcc -Wall -nostdlib -ffreestanding -m32 -g -c "system.c" -o "system.o"
nasm "kernel_enrty.asm" -f elf32 -o "kernel_entry.o"
nasm "start.asm" -f elf32 -o "start.o"
x86_64-elf-ld -nostdlib -o "full_kernel.bin" -Ttext 0x1000 "kernel_entry.o" "start.o" "idt.o" "system.o"  "kernel.o"  --oformat binary -m elf_i386
nasm "boot.asm" -f bin -o "boot.bin"
cat "boot.bin" "full_kernel.bin" > "everything.bin"
nasm "padding.asm" -f bin -o "padding.bin"
cat "everything.bin" "padding.bin" > "OS.bin"