集会:
[BITS 16]
global _start
_start:
mov ax, 0x07C0
mov ds, ax
mov si, hw
call print_string
jmp $
print_string:
mov ah, 0x0E
.char:
lodsb
cmp al, 0
je .exit
int 0x10
jmp .char
.exit: ret
times 0x100-($-$$) db 0
hw: db "Hello, World!", 0
times 510-($-$$) db 0
dw 0xAA55
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组装这个:
$ nasm file.asm -felf -o file.o
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然后将其与:
$ ld -melf_i386 -o file.bin file.o --oformat binary
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给出以下错误:
file.asm:(.text+0x6): relocation truncated to fit: R_386_16 against `.text'
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在稍微摆弄代码后,我发现更改mov si, hw …
应该是一个函数返回指向堆上分配的内存的指针吗?
换句话说,下列哪种方法更"正确"?
// Method #1
Object* getObject1() {
return new Object();
}
// Method #2
std::shared_ptr<Object> getObject2() {
return std::make_shared<Object>();
}
int main() {
// Usage of method #1
Object* o1 = getObject1();
o1->doSomething();
delete o1; // object has to be deleted by user
// Usage of method #2
std::shared_ptr<Object>& o2 getObject2(); // has to be kept in shared_ptr
o2.get()->doSomething();
// object is deleted when o2 destructs
}
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我想第一种方法可能更快,但第二种方法不需要用户删除对象.
assembly ×1
bootloader ×1
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function ×1
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ld ×1
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x86-16 ×1