自定义内核不读取全局变量和 char*
Custom kernel not reading global variables and char*
我有一个自定义 bootloader 启动到自定义内核。我正在用 C 编写，现在程序集已经不在了。
到目前为止，局部变量和方法工作正常，但编译时无法识别全局变量，运行。
我有这三个功能：
void SetChar(int VidIndex, char c) { //Print a single char to a mem index set by VidIndex : WORKS!!
char* vidPtr = (char*)0xb8000;
vidPtr += VidIndex * 2;
*vidPtr = c;
}
void PrintString(char* string) { //Print 20 chars of a string, as a test : NOT WORKS
char* ptr = string;
for (int t = 0; t < 20; t++) {
SetChar(t, *ptr);
ptr++;
}
}
void ClearScreen() { //Sets all chars in Video Memory to empty : WORKS!!
for (char* ptr = (char*)0xb8000; ptr < (char*)(0xb8000 + 4000); ptr+=0x02) {
*ptr = ' ';
}
}
使用像这样的主函数工作正常并且可以做我想要的：
void _main() {
ClearScreen();
SetChar(5, 'H');
SetChar(6, 'e');
SetChar(7, 'l');
SetChar(8, 'l');
SetChar(9, 'o');
return ;
}
然而，
如果我这样做：
char* WelcomeString = "Welcome to my 32 bit OS with a C kernel.";
void _main() {
ClearScreen();
PrintString(WelcomeString);
return ;
}
然后图像是完全黑色的，上面什么也没有。
查看二进制数据表明 char* 字节未编译到其中。这也不适用于其他全局变量。
我正在像这样在 .bat 中编译和链接：
nasm "C:\Users\Braiden\source\repos\Operating System\Bootloader.asm" -o bootloader.bin -f bin -i "C:\Users\Braiden\source\repos\Operating System"
nasm "C:\Users\Braiden\source\repos\Operating System\kernel_entry.asm" -f elf64 -o kernel_entry.o
nasm "C:\Users\Braiden\source\repos\Operating System\padding.asm" -o padding.bin -f bin
gcc -ffreestanding -c "C:\Users\Braiden\source\repos\Operating System\Kernel.c" -o kernel.o
ld -o kernel.tmp -Ttext 0x1000 kernel_entry.o kernel.o
objcopy -O binary -j .text kernel.tmp kernel.bin
copy /b bootloader.bin+kernel.bin+padding.bin os-image.img
pause
它这样做的原因可能是什么？这对我来说非常 st运行ge。
如果需要，我愿意提供更多信息。我只是不确定我需要提供什么。
编辑：
Bootloader.asm
global _start
_start:
[bits 16]
[org 0x7c00]
KERNEL_ENTRY equ 0x1000
mov bp, 0x8000
mov sp, bp
mov bx, welcomeString
call print_func
mov [ BOOT_DRIVE ], dl ; BIOS stores our boot drive in DL , so it ’s
; best to remember this for later.
mov bp, 0x7c00 ; Here we set our stack safely out of the
mov sp, bp ; way , at 0 x8000
mov bx, KERNEL_ENTRY ; Load 5 sectors to 0x0000 (es):KERNEL_ENTRY (bx)
mov dh, 41 ; from the boot disk.
mov dl, [ BOOT_DRIVE ]
call ReadDisk
mov bx, readSuccessString ; Print Success after reading disk
call print_func
mov bx, 0x7e00 ; Let's see if we loaded the area
call print_hex_func ; correctly
call print_newline_func
call PrintAddress
call print_newline_func
jmp switch_to_pm
jmp $
%include "io.asm"
%include "print.asm"
%include "gdt.asm"
welcomeString:
db 'Hello. Welcome to OS', 13, 10,0
readSuccessString:
db 'Disk read Success', 13, 10, 0
switch_to_pm:
cli
lgdt [gdt_descriptor]
mov eax, cr0
or eax, 0x1
mov cr0, eax
jmp CODE_SEG:init_pm
[bits 32]
init_pm:
mov ax, DATA_SEG
mov ds, ax
mov ss, ax
mov es, ax
mov fs, ax
mov gs, ax
mov ebp, 0x90000
mov esp, ebp
jmp BEGIN_PM
BEGIN_PM:
jmp KERNEL_ENTRY ; jump out of our 512 byte sector into the rest of our loaded memory
; so we have much more space to work, and start the kernel
jmp $
MSG_PM:
db 'success', 0
times 510-($-$$) db 0
dw 0xaa55
kernel_entry.asm
[bits 32]
[extern _main]
call _main
jmp $
gcc -v 输出：（使用 MinGW）
Using built-in specs.
COLLECT_GCC=C:\ProgramData\chocolatey\lib\mingw\tools\install\mingw64\bin\gcc.exe
Target: x86_64-w64-mingw32
Configured with: ../../../src/gcc-8.1.0/configure --host=x86_64-w64-mingw32 --build=x86_64-w64-mingw32 --target=x86_64-w64-mingw32 --prefix=/mingw64 --with-sysroot=/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64 --enable-shared --enable-static --disable-multilib --enable-languages=c,c++,fortran,lto --enable-libstdcxx-time=yes --enable-threads=posix --enable-libgomp --enable-libatomic --enable-lto --enable-graphite --enable-checking=release --enable-fully-dynamic-string --enable-version-specific-runtime-libs --disable-libstdcxx-pch --disable-libstdcxx-debug --enable-bootstrap --disable-rpath --disable-win32-registry --disable-nls --disable-werror --disable-symvers --with-gnu-as --with-gnu-ld --with-arch=nocona --with-tune=core2 --with-libiconv --with-system-zlib --with-gmp=/c/mingw810/prerequisites/x86_64-w64-mingw32-static --with-mpfr=/c/mingw810/prerequisites/x86_64-w64-mingw32-static --with-mpc=/c/mingw810/prerequisites/x86_64-w64-mingw32-static --with-isl=/c/mingw810/prerequisites/x86_64-w64-mingw32-static --with-pkgversion='x86_64-posix-seh-rev0, Built by MinGW-W64 project' --with-bugurl=https://sourceforge.net/projects/mingw-w64 CFLAGS='-O2 -pipe -fno-ident -I/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/opt/include -I/c/mingw810/prerequisites/x86_64-zlib-static/include -I/c/mingw810/prerequisites/x86_64-w64-mingw32-static/include' CXXFLAGS='-O2 -pipe -fno-ident -I/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/opt/include -I/c/mingw810/prerequisites/x86_64-zlib-static/include -I/c/mingw810/prerequisites/x86_64-w64-mingw32-static/include' CPPFLAGS=' -I/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/opt/include -I/c/mingw810/prerequisites/x86_64-zlib-static/include -I/c/mingw810/prerequisites/x86_64-w64-mingw32-static/include' LDFLAGS='-pipe -fno-ident -L/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/opt/lib -L/c/mingw810/prerequisites/x86_64-zlib-static/lib -L/c/mingw810/prerequisites/x86_64-w64-mingw32-static/lib '
Thread model: posix
gcc version 8.1.0 (x86_64-posix-seh-rev0, Built by MinGW-W64 project)
COLLECT_GCC_OPTIONS='-v' '-ffreestanding' '-c' '-o' 'kernel.o' '-mtune=core2' '-march=nocona'
C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../libexec/gcc/x86_64-w64-mingw32/8.1.0/cc1.exe -quiet -v -iprefix C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/ -D_REENTRANT C:\Users\Braiden\source\repos\Operating System\Kernel.c -quiet -dumpbase Kernel.c -mtune=core2 -march=nocona -auxbase-strip kernel.o -version -ffreestanding -o C:\Users\Braiden\AppData\Local\Temp\ccTxrZFP.s
GNU C17 (x86_64-posix-seh-rev0, Built by MinGW-W64 project) version 8.1.0 (x86_64-w64-mingw32)
compiled by GNU C version 8.1.0, GMP version 6.1.2, MPFR version 4.0.1, MPC version 1.1.0, isl version isl-0.18-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring duplicate directory "C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/lib/gcc/../../lib/gcc/x86_64-w64-mingw32/8.1.0/include"
ignoring nonexistent directory "C:/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64C:/msys64/mingw64/lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../include"
ignoring duplicate directory "C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/lib/gcc/../../lib/gcc/x86_64-w64-mingw32/8.1.0/include-fixed"
ignoring duplicate directory "C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/lib/gcc/../../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/include"
ignoring nonexistent directory "C:/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/mingw/include"
#include "..." search starts here:
#include <...> search starts here:
C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include
C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include-fixed
C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/include
End of search list.
GNU C17 (x86_64-posix-seh-rev0, Built by MinGW-W64 project) version 8.1.0 (x86_64-w64-mingw32)
compiled by GNU C version 8.1.0, GMP version 6.1.2, MPFR version 4.0.1, MPC version 1.1.0, isl version isl-0.18-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 985ce7ae6dd3a696cd146ca9896b0035
COLLECT_GCC_OPTIONS='-v' '-ffreestanding' '-c' '-o' 'kernel.o' '-mtune=core2' '-march=nocona'
C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/bin/as.exe -v -o kernel.o C:\Users\Braiden\AppData\Local\Temp\ccTxrZFP.s
GNU assembler version 2.30 (x86_64-w64-mingw32) using BFD version (GNU Binutils) 2.30
COMPILER_PATH=C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../libexec/gcc/x86_64-w64-mingw32/8.1.0/;C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../libexec/gcc/;C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/bin/
LIBRARY_PATH=C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/;C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/;C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/lib/../lib/;C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../lib/;C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/lib/;C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../
COLLECT_GCC_OPTIONS='-v' '-ffreestanding' '-c' '-o' 'kernel.o' '-mtune=core2' '-march=nocona'
objdump -x kernel.tmp
kernel.tmp: file format pei-x86-64
kernel.tmp
architecture: i386:x86-64, flags 0x00000132:
EXEC_P, HAS_SYMS, HAS_LOCALS, D_PAGED
start address 0x0000000100001000
Characteristics 0x227
relocations stripped
executable
line numbers stripped
large address aware
debugging information removed
Time/Date Sun Jun 21 02:05:38 2020
Magic 020b (PE32+)
MajorLinkerVersion 2
MinorLinkerVersion 30
SizeOfCode 00000200
SizeOfInitializedData 00000a00
SizeOfUninitializedData 00000000
AddressOfEntryPoint 00000000ffc01000
BaseOfCode 00000000ffc01000
ImageBase 0000000000400000
SectionAlignment 0000000000001000
FileAlignment 0000000000000200
MajorOSystemVersion 4
MinorOSystemVersion 0
MajorImageVersion 0
MinorImageVersion 0
MajorSubsystemVersion 5
MinorSubsystemVersion 2
Win32Version 00000000
SizeOfImage ffc07000
SizeOfHeaders 00000400
CheckSum 00006de2
Subsystem 00000003 (Windows CUI)
DllCharacteristics 00000000
SizeOfStackReserve 0000000000200000
SizeOfStackCommit 0000000000001000
SizeOfHeapReserve 0000000000100000
SizeOfHeapCommit 0000000000001000
LoaderFlags 00000000
NumberOfRvaAndSizes 00000010
The Data Directory
Entry 0 0000000000000000 00000000 Export Directory [.edata (or where ever we found it)]
Entry 1 00000000ffc06000 00000014 Import Directory [parts of .idata]
Entry 2 0000000000000000 00000000 Resource Directory [.rsrc]
Entry 3 00000000ffc04000 00000030 Exception Directory [.pdata]
Entry 4 0000000000000000 00000000 Security Directory
Entry 5 0000000000000000 00000000 Base Relocation Directory [.reloc]
Entry 6 0000000000000000 00000000 Debug Directory
Entry 7 0000000000000000 00000000 Description Directory
Entry 8 0000000000000000 00000000 Special Directory
Entry 9 0000000000000000 00000000 Thread Storage Directory [.tls]
Entry a 0000000000000000 00000000 Load Configuration Directory
Entry b 0000000000000000 00000000 Bound Import Directory
Entry c 0000000000000000 00000000 Import Address Table Directory
Entry d 0000000000000000 00000000 Delay Import Directory
Entry e 0000000000000000 00000000 CLR Runtime Header
Entry f 0000000000000000 00000000 Reserved
There is an import table in .idata at 0x6000
The Import Tables (interpreted .idata section contents)
vma: Hint Time Forward DLL First
Table Stamp Chain Name Thunk
ffc06000 00000000 00000000 00000000 00000000 00000000
The Function Table (interpreted .pdata section contents)
vma: BeginAddress EndAddress UnwindData
0000000100004000: 0000000100001010 0000000100001044 0000000100005000
has negative begin address
has negative end address
has negative unwind address
000000010000400c: 0000000100001044 000000010000108b 000000010000500c
has negative begin address
has negative end address
has negative unwind address
0000000100004018: 000000010000108b 00000001000010ba 0000000100005018
has negative begin address
has negative end address
has negative unwind address
0000000100004024: 00000001000010ba 00000001000010dd 0000000100005024
has negative begin address
has negative end address
has negative unwind address
Sections:
Idx Name Size VMA LMA File off Algn
0 .text 00000100 0000000100001000 0000000100001000 00000400 2**4
CONTENTS, ALLOC, LOAD, READONLY, CODE
1 .data 00000010 0000000100002000 0000000100002000 00000600 2**4
CONTENTS, ALLOC, LOAD, DATA
2 .rdata 00000070 0000000100003000 0000000100003000 00000800 2**4
CONTENTS, ALLOC, LOAD, READONLY, DATA
3 .pdata 00000030 0000000100004000 0000000100004000 00000a00 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
4 .xdata 00000030 0000000100005000 0000000100005000 00000c00 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
5 .idata 00000014 0000000100006000 0000000100006000 00000e00 2**2
CONTENTS, ALLOC, LOAD, DATA
SYMBOL TABLE:
[ 0](sec -2)(fl 0x00)(ty 0)(scl 103) (nx 1) 0x0000000000000013 Kernel.c
File
[ 2](sec 1)(fl 0x00)(ty 20)(scl 2) (nx 1) 0x0000000000000010 SetChar
AUX tagndx 0 ttlsiz 0x0 lnnos 0 next 0
[ 4](sec 1)(fl 0x00)(ty 20)(scl 2) (nx 0) 0x0000000000000044 PrintString
[ 5](sec 1)(fl 0x00)(ty 20)(scl 2) (nx 0) 0x000000000000008b ClearScreen
[ 6](sec 1)(fl 0x00)(ty 20)(scl 2) (nx 0) 0x00000000000000ba _main
[ 7](sec 1)(fl 0x00)(ty 0)(scl 3) (nx 1) 0x0000000000000010 .text
AUX scnlen 0xcd nreloc 1 nlnno 0
[ 9](sec 2)(fl 0x00)(ty 0)(scl 3) (nx 1) 0x0000000000000000 .data
AUX scnlen 0x8 nreloc 1 nlnno 0
[ 11](sec 5)(fl 0x00)(ty 0)(scl 3) (nx 1) 0x0000000000000000 .xdata
AUX scnlen 0x30 nreloc 0 nlnno 0
[ 13](sec 4)(fl 0x00)(ty 0)(scl 3) (nx 1) 0x0000000000000000 .pdata
AUX scnlen 0x30 nreloc 12 nlnno 0
[ 15](sec 3)(fl 0x00)(ty 0)(scl 3) (nx 1) 0x0000000000000000 .rdata
AUX scnlen 0x29 nreloc 0 nlnno 0
[ 17](sec 3)(fl 0x00)(ty 0)(scl 3) (nx 1) 0x0000000000000030 .rdata$zzz
AUX scnlen 0x3f nreloc 0 nlnno 0
[ 19](sec -2)(fl 0x00)(ty 0)(scl 103) (nx 1) 0x0000000000000015 C:\Users\Braiden\source\repos\Operating System\kernel_entry.asm
File
[ 21](sec 3)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000070 ___RUNTIME_PSEUDO_RELOC_LIST__
[ 22](sec 2)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __data_start__
[ 23](sec 1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x00000000000000f0 ___DTOR_LIST__
[ 24](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___tls_start__
[ 25](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000400000 __ImageBase
[ 26](sec 3)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000070 __rt_psrelocs_start
[ 27](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __dll_characteristics__
[ 28](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 __size_of_stack_commit__
[ 29](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000200000 __size_of_stack_reserve__
[ 30](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000005 __major_subsystem_version__
[ 31](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___crt_xl_start__
[ 32](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___crt_xi_start__
[ 33](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___crt_xi_end__
[ 34](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __bss_start__
[ 35](sec 3)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000070 ___RUNTIME_PSEUDO_RELOC_LIST_END__
[ 36](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 __size_of_heap_commit__
[ 37](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___crt_xp_start__
[ 38](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___crt_xp_end__
[ 39](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __dll__
[ 40](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __minor_os_version__
[ 41](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000400000 __image_base__
[ 42](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 __section_alignment__
[ 43](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000014 __IAT_end__
[ 44](sec 3)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000070 __RUNTIME_PSEUDO_RELOC_LIST__
[ 45](sec 2)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 WelcomeString
[ 46](sec 2)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000010 __data_end__
[ 47](sec 1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x00000000000000e0 __CTOR_LIST__
[ 48](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __bss_end__
[ 49](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___crt_xc_end__
[ 50](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___crt_xc_start__
[ 51](sec 1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x00000000000000e0 ___CTOR_LIST__
[ 52](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __rt_psrelocs_size
[ 53](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000200 __file_alignment__
[ 54](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000004 __major_os_version__
[ 55](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000014 __IAT_start__
[ 56](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 __end__
[ 57](sec 1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x00000000000000f0 __DTOR_LIST__
[ 58](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000100000 __size_of_heap_reserve__
[ 59](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___crt_xt_start__
[ 60](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000003 __subsystem__
[ 61](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___tls_end__
[ 62](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __major_image_version__
[ 63](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __loader_flags__
[ 64](sec 3)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000070 __rt_psrelocs_end
[ 65](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000002 __minor_subsystem_version__
[ 66](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __minor_image_version__
[ 67](sec 3)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000070 __RUNTIME_PSEUDO_RELOC_LIST_END__
[ 68](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___crt_xt_end__
确保您的自定义引导加载程序正在读取整个内核。您是否读取了足够多的扇区以确保整个内核都在内存中？我可以从你所展示的内容中识别出来的一个问题是你如何生成 kernel.bin。你这样做：
objcopy -O binary -j .text kernel.tmp kernel.bin
这只会将 .text 部分（代码）放入 kernel.bin 中，仅此而已。您未打印的字符串可能在您忽略包含在内核中的 .rdata* 部分中。我将包括所有部分：
objcopy -O binary kernel.tmp kernel.bin
这似乎与另一个最近已删除的 SO 问题有关，该问题非常相似并交叉发布到 OSDev Forum。那里的问题似乎与这里相同。
原始问题已根据要求进行了修改，提供了更多详细信息。正在读取的扇区数不足以覆盖内核的大小。
发现了另一个问题。编译器是64位的MinGWWindows编译器；引导加载程序仅将处理器置于 32 位保护模式；并且生成的代码是 64 位代码。您无法在 32 位保护模式下正确 运行 64 位代码。该代码可能部分 运行 正确，但它最终会表现出异常和不需要的行为。
您的选择是将处理器置于 64-bit long mode as part of your custom bootloader or have your compiler, assembler, and linker generate 32-bit objects and executables. I touch on this issue in another related 。
您可以更改 nasm 以使用 -felf32 到 assemble 以使用 32 位对象。由于您使用的是 Windows 本机 GCC 编译器，因此您也可以使用 -fwin32。要将 GCC 代码编译为 32 位，您可以使用 -m32 选项，而链接器 (ld) 需要 -mi386pe 选项。当涉及 OSDev with Windows 编译器时，您可能希望与链接一起使用的另一个选项是 LD 的 -N 选项，它定义为：
-N, --omagic Do not page align data, do not make text readonly
综上所述，如果生成 32 位代码，使用 i386 或 i686 ELF 交叉编译器，如果针对 [=75 的 64 位代码，则使用 64 位 ELF 交叉编译器，可以省去很多麻烦=] 发展。有关 building/using Windows 交叉编译器的更多信息，请参阅此 tutorial and the OSDev wiki has a section on GCC cross compilers 大体。
附加信息
如果生成 32 位 Windows 对象和可执行文件，全局范围内的非静态函数需要在它们前面加上 _。这些下划线由 GCC 自动生成，但在您从汇编代码中引用它们时必须添加。这同样适用于您创建的将从 C 代码调用的汇编函数。如果您编译并 assemble 您的代码，您将得到一个未定义的引用，因为您这样声明 main：
void _main() {
GCC MinGW 编译器将在开头附加下划线，并将函数命名为 __main。您需要修改汇编代码以使用 __main 而不是像您的代码当前那样使用 _main 。但更容易的是将声明更改为：
void main() {
这将生成一个名为 _main 的函数，这是您的汇编代码当前期望的函数名称。
64 位 Windows 对象和可执行文件不需要或生成全局范围内带有前缀 _ 的函数。这就是生成 64 位代码时这不是问题的原因。
我一直在编译 64 位二进制文件，同时我启动到 32 位保护模式。以 32 位编译和链接它们解决了这个问题。这引发了外部函数前缀“_”的另一个问题，仅通过更新方法名称修复了该问题，因此前缀不会导致问题。
我最后的编译和链接命令：
nasm "C:\Users\Braiden\source\repos\Operating System\Bootloader.asm" -o bootloader.bin -f bin -i "C:\Users\Braiden\source\repos\Operating System"
nasm "C:\Users\Braiden\source\repos\Operating System\kernel_entry.asm" -f elf32 -o kernel_entry.o
nasm "C:\Users\Braiden\source\repos\Operating System\padding.asm" -o padding.bin -f bin
gcc -ffreestanding -m32 -c "C:\Users\Braiden\source\repos\Operating System\Kernel.c" -o kernel.o
ld -o kernel.tmp -Ttext 0x1000 kernel_entry.o kernel.o -mi386pe
objcopy -O binary kernel.tmp kernel.bin
copy /b bootloader.bin+kernel.bin+padding.bin os-image.img
我有一个自定义 bootloader 启动到自定义内核。我正在用 C 编写，现在程序集已经不在了。
到目前为止，局部变量和方法工作正常，但编译时无法识别全局变量，运行。
我有这三个功能：
void SetChar(int VidIndex, char c) { //Print a single char to a mem index set by VidIndex : WORKS!!
char* vidPtr = (char*)0xb8000;
vidPtr += VidIndex * 2;
*vidPtr = c;
}
void PrintString(char* string) { //Print 20 chars of a string, as a test : NOT WORKS
char* ptr = string;
for (int t = 0; t < 20; t++) {
SetChar(t, *ptr);
ptr++;
}
}
void ClearScreen() { //Sets all chars in Video Memory to empty : WORKS!!
for (char* ptr = (char*)0xb8000; ptr < (char*)(0xb8000 + 4000); ptr+=0x02) {
*ptr = ' ';
}
}
使用像这样的主函数工作正常并且可以做我想要的：
void _main() {
ClearScreen();
SetChar(5, 'H');
SetChar(6, 'e');
SetChar(7, 'l');
SetChar(8, 'l');
SetChar(9, 'o');
return ;
}
然而， 如果我这样做：
char* WelcomeString = "Welcome to my 32 bit OS with a C kernel.";
void _main() {
ClearScreen();
PrintString(WelcomeString);
return ;
}
然后图像是完全黑色的，上面什么也没有。 查看二进制数据表明 char* 字节未编译到其中。这也不适用于其他全局变量。 我正在像这样在 .bat 中编译和链接：
nasm "C:\Users\Braiden\source\repos\Operating System\Bootloader.asm" -o bootloader.bin -f bin -i "C:\Users\Braiden\source\repos\Operating System"
nasm "C:\Users\Braiden\source\repos\Operating System\kernel_entry.asm" -f elf64 -o kernel_entry.o
nasm "C:\Users\Braiden\source\repos\Operating System\padding.asm" -o padding.bin -f bin
gcc -ffreestanding -c "C:\Users\Braiden\source\repos\Operating System\Kernel.c" -o kernel.o
ld -o kernel.tmp -Ttext 0x1000 kernel_entry.o kernel.o
objcopy -O binary -j .text kernel.tmp kernel.bin
copy /b bootloader.bin+kernel.bin+padding.bin os-image.img
pause
它这样做的原因可能是什么？这对我来说非常 st运行ge。 如果需要，我愿意提供更多信息。我只是不确定我需要提供什么。
编辑： Bootloader.asm
global _start
_start:
[bits 16]
[org 0x7c00]
KERNEL_ENTRY equ 0x1000
mov bp, 0x8000
mov sp, bp
mov bx, welcomeString
call print_func
mov [ BOOT_DRIVE ], dl ; BIOS stores our boot drive in DL , so it ’s
; best to remember this for later.
mov bp, 0x7c00 ; Here we set our stack safely out of the
mov sp, bp ; way , at 0 x8000
mov bx, KERNEL_ENTRY ; Load 5 sectors to 0x0000 (es):KERNEL_ENTRY (bx)
mov dh, 41 ; from the boot disk.
mov dl, [ BOOT_DRIVE ]
call ReadDisk
mov bx, readSuccessString ; Print Success after reading disk
call print_func
mov bx, 0x7e00 ; Let's see if we loaded the area
call print_hex_func ; correctly
call print_newline_func
call PrintAddress
call print_newline_func
jmp switch_to_pm
jmp $
%include "io.asm"
%include "print.asm"
%include "gdt.asm"
welcomeString:
db 'Hello. Welcome to OS', 13, 10,0
readSuccessString:
db 'Disk read Success', 13, 10, 0
switch_to_pm:
cli
lgdt [gdt_descriptor]
mov eax, cr0
or eax, 0x1
mov cr0, eax
jmp CODE_SEG:init_pm
[bits 32]
init_pm:
mov ax, DATA_SEG
mov ds, ax
mov ss, ax
mov es, ax
mov fs, ax
mov gs, ax
mov ebp, 0x90000
mov esp, ebp
jmp BEGIN_PM
BEGIN_PM:
jmp KERNEL_ENTRY ; jump out of our 512 byte sector into the rest of our loaded memory
; so we have much more space to work, and start the kernel
jmp $
MSG_PM:
db 'success', 0
times 510-($-$$) db 0
dw 0xaa55
kernel_entry.asm
[bits 32]
[extern _main]
call _main
jmp $
gcc -v 输出：（使用 MinGW）
Using built-in specs.
COLLECT_GCC=C:\ProgramData\chocolatey\lib\mingw\tools\install\mingw64\bin\gcc.exe
Target: x86_64-w64-mingw32
Configured with: ../../../src/gcc-8.1.0/configure --host=x86_64-w64-mingw32 --build=x86_64-w64-mingw32 --target=x86_64-w64-mingw32 --prefix=/mingw64 --with-sysroot=/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64 --enable-shared --enable-static --disable-multilib --enable-languages=c,c++,fortran,lto --enable-libstdcxx-time=yes --enable-threads=posix --enable-libgomp --enable-libatomic --enable-lto --enable-graphite --enable-checking=release --enable-fully-dynamic-string --enable-version-specific-runtime-libs --disable-libstdcxx-pch --disable-libstdcxx-debug --enable-bootstrap --disable-rpath --disable-win32-registry --disable-nls --disable-werror --disable-symvers --with-gnu-as --with-gnu-ld --with-arch=nocona --with-tune=core2 --with-libiconv --with-system-zlib --with-gmp=/c/mingw810/prerequisites/x86_64-w64-mingw32-static --with-mpfr=/c/mingw810/prerequisites/x86_64-w64-mingw32-static --with-mpc=/c/mingw810/prerequisites/x86_64-w64-mingw32-static --with-isl=/c/mingw810/prerequisites/x86_64-w64-mingw32-static --with-pkgversion='x86_64-posix-seh-rev0, Built by MinGW-W64 project' --with-bugurl=https://sourceforge.net/projects/mingw-w64 CFLAGS='-O2 -pipe -fno-ident -I/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/opt/include -I/c/mingw810/prerequisites/x86_64-zlib-static/include -I/c/mingw810/prerequisites/x86_64-w64-mingw32-static/include' CXXFLAGS='-O2 -pipe -fno-ident -I/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/opt/include -I/c/mingw810/prerequisites/x86_64-zlib-static/include -I/c/mingw810/prerequisites/x86_64-w64-mingw32-static/include' CPPFLAGS=' -I/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/opt/include -I/c/mingw810/prerequisites/x86_64-zlib-static/include -I/c/mingw810/prerequisites/x86_64-w64-mingw32-static/include' LDFLAGS='-pipe -fno-ident -L/c/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/opt/lib -L/c/mingw810/prerequisites/x86_64-zlib-static/lib -L/c/mingw810/prerequisites/x86_64-w64-mingw32-static/lib '
Thread model: posix
gcc version 8.1.0 (x86_64-posix-seh-rev0, Built by MinGW-W64 project)
COLLECT_GCC_OPTIONS='-v' '-ffreestanding' '-c' '-o' 'kernel.o' '-mtune=core2' '-march=nocona'
C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../libexec/gcc/x86_64-w64-mingw32/8.1.0/cc1.exe -quiet -v -iprefix C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/ -D_REENTRANT C:\Users\Braiden\source\repos\Operating System\Kernel.c -quiet -dumpbase Kernel.c -mtune=core2 -march=nocona -auxbase-strip kernel.o -version -ffreestanding -o C:\Users\Braiden\AppData\Local\Temp\ccTxrZFP.s
GNU C17 (x86_64-posix-seh-rev0, Built by MinGW-W64 project) version 8.1.0 (x86_64-w64-mingw32)
compiled by GNU C version 8.1.0, GMP version 6.1.2, MPFR version 4.0.1, MPC version 1.1.0, isl version isl-0.18-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
ignoring duplicate directory "C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/lib/gcc/../../lib/gcc/x86_64-w64-mingw32/8.1.0/include"
ignoring nonexistent directory "C:/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64C:/msys64/mingw64/lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../include"
ignoring duplicate directory "C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/lib/gcc/../../lib/gcc/x86_64-w64-mingw32/8.1.0/include-fixed"
ignoring duplicate directory "C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/lib/gcc/../../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/include"
ignoring nonexistent directory "C:/mingw810/x86_64-810-posix-seh-rt_v6-rev0/mingw64/mingw/include"
#include "..." search starts here:
#include <...> search starts here:
C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include
C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/include-fixed
C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/include
End of search list.
GNU C17 (x86_64-posix-seh-rev0, Built by MinGW-W64 project) version 8.1.0 (x86_64-w64-mingw32)
compiled by GNU C version 8.1.0, GMP version 6.1.2, MPFR version 4.0.1, MPC version 1.1.0, isl version isl-0.18-GMP
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: 985ce7ae6dd3a696cd146ca9896b0035
COLLECT_GCC_OPTIONS='-v' '-ffreestanding' '-c' '-o' 'kernel.o' '-mtune=core2' '-march=nocona'
C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/bin/as.exe -v -o kernel.o C:\Users\Braiden\AppData\Local\Temp\ccTxrZFP.s
GNU assembler version 2.30 (x86_64-w64-mingw32) using BFD version (GNU Binutils) 2.30
COMPILER_PATH=C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../libexec/gcc/x86_64-w64-mingw32/8.1.0/;C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../libexec/gcc/;C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/bin/
LIBRARY_PATH=C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/;C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/;C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/lib/../lib/;C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../lib/;C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../../x86_64-w64-mingw32/lib/;C:/ProgramData/chocolatey/lib/mingw/tools/install/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/8.1.0/../../../
COLLECT_GCC_OPTIONS='-v' '-ffreestanding' '-c' '-o' 'kernel.o' '-mtune=core2' '-march=nocona'
objdump -x kernel.tmp
kernel.tmp: file format pei-x86-64
kernel.tmp
architecture: i386:x86-64, flags 0x00000132:
EXEC_P, HAS_SYMS, HAS_LOCALS, D_PAGED
start address 0x0000000100001000
Characteristics 0x227
relocations stripped
executable
line numbers stripped
large address aware
debugging information removed
Time/Date Sun Jun 21 02:05:38 2020
Magic 020b (PE32+)
MajorLinkerVersion 2
MinorLinkerVersion 30
SizeOfCode 00000200
SizeOfInitializedData 00000a00
SizeOfUninitializedData 00000000
AddressOfEntryPoint 00000000ffc01000
BaseOfCode 00000000ffc01000
ImageBase 0000000000400000
SectionAlignment 0000000000001000
FileAlignment 0000000000000200
MajorOSystemVersion 4
MinorOSystemVersion 0
MajorImageVersion 0
MinorImageVersion 0
MajorSubsystemVersion 5
MinorSubsystemVersion 2
Win32Version 00000000
SizeOfImage ffc07000
SizeOfHeaders 00000400
CheckSum 00006de2
Subsystem 00000003 (Windows CUI)
DllCharacteristics 00000000
SizeOfStackReserve 0000000000200000
SizeOfStackCommit 0000000000001000
SizeOfHeapReserve 0000000000100000
SizeOfHeapCommit 0000000000001000
LoaderFlags 00000000
NumberOfRvaAndSizes 00000010
The Data Directory
Entry 0 0000000000000000 00000000 Export Directory [.edata (or where ever we found it)]
Entry 1 00000000ffc06000 00000014 Import Directory [parts of .idata]
Entry 2 0000000000000000 00000000 Resource Directory [.rsrc]
Entry 3 00000000ffc04000 00000030 Exception Directory [.pdata]
Entry 4 0000000000000000 00000000 Security Directory
Entry 5 0000000000000000 00000000 Base Relocation Directory [.reloc]
Entry 6 0000000000000000 00000000 Debug Directory
Entry 7 0000000000000000 00000000 Description Directory
Entry 8 0000000000000000 00000000 Special Directory
Entry 9 0000000000000000 00000000 Thread Storage Directory [.tls]
Entry a 0000000000000000 00000000 Load Configuration Directory
Entry b 0000000000000000 00000000 Bound Import Directory
Entry c 0000000000000000 00000000 Import Address Table Directory
Entry d 0000000000000000 00000000 Delay Import Directory
Entry e 0000000000000000 00000000 CLR Runtime Header
Entry f 0000000000000000 00000000 Reserved
There is an import table in .idata at 0x6000
The Import Tables (interpreted .idata section contents)
vma: Hint Time Forward DLL First
Table Stamp Chain Name Thunk
ffc06000 00000000 00000000 00000000 00000000 00000000
The Function Table (interpreted .pdata section contents)
vma: BeginAddress EndAddress UnwindData
0000000100004000: 0000000100001010 0000000100001044 0000000100005000
has negative begin address
has negative end address
has negative unwind address
000000010000400c: 0000000100001044 000000010000108b 000000010000500c
has negative begin address
has negative end address
has negative unwind address
0000000100004018: 000000010000108b 00000001000010ba 0000000100005018
has negative begin address
has negative end address
has negative unwind address
0000000100004024: 00000001000010ba 00000001000010dd 0000000100005024
has negative begin address
has negative end address
has negative unwind address
Sections:
Idx Name Size VMA LMA File off Algn
0 .text 00000100 0000000100001000 0000000100001000 00000400 2**4
CONTENTS, ALLOC, LOAD, READONLY, CODE
1 .data 00000010 0000000100002000 0000000100002000 00000600 2**4
CONTENTS, ALLOC, LOAD, DATA
2 .rdata 00000070 0000000100003000 0000000100003000 00000800 2**4
CONTENTS, ALLOC, LOAD, READONLY, DATA
3 .pdata 00000030 0000000100004000 0000000100004000 00000a00 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
4 .xdata 00000030 0000000100005000 0000000100005000 00000c00 2**2
CONTENTS, ALLOC, LOAD, READONLY, DATA
5 .idata 00000014 0000000100006000 0000000100006000 00000e00 2**2
CONTENTS, ALLOC, LOAD, DATA
SYMBOL TABLE:
[ 0](sec -2)(fl 0x00)(ty 0)(scl 103) (nx 1) 0x0000000000000013 Kernel.c
File
[ 2](sec 1)(fl 0x00)(ty 20)(scl 2) (nx 1) 0x0000000000000010 SetChar
AUX tagndx 0 ttlsiz 0x0 lnnos 0 next 0
[ 4](sec 1)(fl 0x00)(ty 20)(scl 2) (nx 0) 0x0000000000000044 PrintString
[ 5](sec 1)(fl 0x00)(ty 20)(scl 2) (nx 0) 0x000000000000008b ClearScreen
[ 6](sec 1)(fl 0x00)(ty 20)(scl 2) (nx 0) 0x00000000000000ba _main
[ 7](sec 1)(fl 0x00)(ty 0)(scl 3) (nx 1) 0x0000000000000010 .text
AUX scnlen 0xcd nreloc 1 nlnno 0
[ 9](sec 2)(fl 0x00)(ty 0)(scl 3) (nx 1) 0x0000000000000000 .data
AUX scnlen 0x8 nreloc 1 nlnno 0
[ 11](sec 5)(fl 0x00)(ty 0)(scl 3) (nx 1) 0x0000000000000000 .xdata
AUX scnlen 0x30 nreloc 0 nlnno 0
[ 13](sec 4)(fl 0x00)(ty 0)(scl 3) (nx 1) 0x0000000000000000 .pdata
AUX scnlen 0x30 nreloc 12 nlnno 0
[ 15](sec 3)(fl 0x00)(ty 0)(scl 3) (nx 1) 0x0000000000000000 .rdata
AUX scnlen 0x29 nreloc 0 nlnno 0
[ 17](sec 3)(fl 0x00)(ty 0)(scl 3) (nx 1) 0x0000000000000030 .rdata$zzz
AUX scnlen 0x3f nreloc 0 nlnno 0
[ 19](sec -2)(fl 0x00)(ty 0)(scl 103) (nx 1) 0x0000000000000015 C:\Users\Braiden\source\repos\Operating System\kernel_entry.asm
File
[ 21](sec 3)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000070 ___RUNTIME_PSEUDO_RELOC_LIST__
[ 22](sec 2)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __data_start__
[ 23](sec 1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x00000000000000f0 ___DTOR_LIST__
[ 24](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___tls_start__
[ 25](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000400000 __ImageBase
[ 26](sec 3)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000070 __rt_psrelocs_start
[ 27](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __dll_characteristics__
[ 28](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 __size_of_stack_commit__
[ 29](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000200000 __size_of_stack_reserve__
[ 30](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000005 __major_subsystem_version__
[ 31](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___crt_xl_start__
[ 32](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___crt_xi_start__
[ 33](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___crt_xi_end__
[ 34](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __bss_start__
[ 35](sec 3)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000070 ___RUNTIME_PSEUDO_RELOC_LIST_END__
[ 36](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 __size_of_heap_commit__
[ 37](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___crt_xp_start__
[ 38](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___crt_xp_end__
[ 39](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __dll__
[ 40](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __minor_os_version__
[ 41](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000400000 __image_base__
[ 42](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 __section_alignment__
[ 43](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000014 __IAT_end__
[ 44](sec 3)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000070 __RUNTIME_PSEUDO_RELOC_LIST__
[ 45](sec 2)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 WelcomeString
[ 46](sec 2)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000010 __data_end__
[ 47](sec 1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x00000000000000e0 __CTOR_LIST__
[ 48](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __bss_end__
[ 49](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___crt_xc_end__
[ 50](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___crt_xc_start__
[ 51](sec 1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x00000000000000e0 ___CTOR_LIST__
[ 52](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __rt_psrelocs_size
[ 53](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000200 __file_alignment__
[ 54](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000004 __major_os_version__
[ 55](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000014 __IAT_start__
[ 56](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 __end__
[ 57](sec 1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x00000000000000f0 __DTOR_LIST__
[ 58](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000100000 __size_of_heap_reserve__
[ 59](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___crt_xt_start__
[ 60](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000003 __subsystem__
[ 61](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___tls_end__
[ 62](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __major_image_version__
[ 63](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __loader_flags__
[ 64](sec 3)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000070 __rt_psrelocs_end
[ 65](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000002 __minor_subsystem_version__
[ 66](sec -1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000000 __minor_image_version__
[ 67](sec 3)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000000070 __RUNTIME_PSEUDO_RELOC_LIST_END__
[ 68](sec 6)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x0000000000001000 ___crt_xt_end__
确保您的自定义引导加载程序正在读取整个内核。您是否读取了足够多的扇区以确保整个内核都在内存中？我可以从你所展示的内容中识别出来的一个问题是你如何生成 kernel.bin。你这样做：
objcopy -O binary -j .text kernel.tmp kernel.bin
这只会将 .text 部分（代码）放入 kernel.bin 中，仅此而已。您未打印的字符串可能在您忽略包含在内核中的 .rdata* 部分中。我将包括所有部分：
objcopy -O binary kernel.tmp kernel.bin
这似乎与另一个最近已删除的 SO 问题有关，该问题非常相似并交叉发布到 OSDev Forum。那里的问题似乎与这里相同。
原始问题已根据要求进行了修改，提供了更多详细信息。正在读取的扇区数不足以覆盖内核的大小。
发现了另一个问题。编译器是64位的MinGWWindows编译器；引导加载程序仅将处理器置于 32 位保护模式；并且生成的代码是 64 位代码。您无法在 32 位保护模式下正确 运行 64 位代码。该代码可能部分 运行 正确，但它最终会表现出异常和不需要的行为。
您的选择是将处理器置于 64-bit long mode as part of your custom bootloader or have your compiler, assembler, and linker generate 32-bit objects and executables. I touch on this issue in another related
您可以更改 nasm 以使用 -felf32 到 assemble 以使用 32 位对象。由于您使用的是 Windows 本机 GCC 编译器，因此您也可以使用 -fwin32。要将 GCC 代码编译为 32 位，您可以使用 -m32 选项，而链接器 (ld) 需要 -mi386pe 选项。当涉及 OSDev with Windows 编译器时，您可能希望与链接一起使用的另一个选项是 LD 的 -N 选项，它定义为：
-N, --omagic Do not page align data, do not make text readonly
综上所述，如果生成 32 位代码，使用 i386 或 i686 ELF 交叉编译器，如果针对 [=75 的 64 位代码，则使用 64 位 ELF 交叉编译器，可以省去很多麻烦=] 发展。有关 building/using Windows 交叉编译器的更多信息，请参阅此 tutorial and the OSDev wiki has a section on GCC cross compilers 大体。
附加信息
如果生成 32 位 Windows 对象和可执行文件，全局范围内的非静态函数需要在它们前面加上 _。这些下划线由 GCC 自动生成，但在您从汇编代码中引用它们时必须添加。这同样适用于您创建的将从 C 代码调用的汇编函数。如果您编译并 assemble 您的代码，您将得到一个未定义的引用，因为您这样声明 main：
void _main() {
GCC MinGW 编译器将在开头附加下划线，并将函数命名为 __main。您需要修改汇编代码以使用 __main 而不是像您的代码当前那样使用 _main 。但更容易的是将声明更改为：
void main() {
这将生成一个名为 _main 的函数，这是您的汇编代码当前期望的函数名称。
64 位 Windows 对象和可执行文件不需要或生成全局范围内带有前缀 _ 的函数。这就是生成 64 位代码时这不是问题的原因。
我一直在编译 64 位二进制文件，同时我启动到 32 位保护模式。以 32 位编译和链接它们解决了这个问题。这引发了外部函数前缀“_”的另一个问题，仅通过更新方法名称修复了该问题，因此前缀不会导致问题。
我最后的编译和链接命令：
nasm "C:\Users\Braiden\source\repos\Operating System\Bootloader.asm" -o bootloader.bin -f bin -i "C:\Users\Braiden\source\repos\Operating System"
nasm "C:\Users\Braiden\source\repos\Operating System\kernel_entry.asm" -f elf32 -o kernel_entry.o
nasm "C:\Users\Braiden\source\repos\Operating System\padding.asm" -o padding.bin -f bin
gcc -ffreestanding -m32 -c "C:\Users\Braiden\source\repos\Operating System\Kernel.c" -o kernel.o
ld -o kernel.tmp -Ttext 0x1000 kernel_entry.o kernel.o -mi386pe
objcopy -O binary kernel.tmp kernel.bin
copy /b bootloader.bin+kernel.bin+padding.bin os-image.img