20230817 chapter3 tooling up 学习make GDB git 等工具
make -B 强制重新make
gdb之前，需要先在编译时加入 -g 参数以开启debug模式,修改一下makefile；
TARGET=move
ifdef DEBUG
DEBUGFLGS = -g
else
DEBUGFLGS =
endif
$(TARGET): $(TARGET).o
ld -o $@ $^
%.o:%.s
as $(DEBUGFLGS) -o $@ $<
clean:
rm *.o $(TARGET)
现在，开启debug模式有2种方式
1，直接 make DEBUG=1
2,在环境变量里面添加 ，
export DEBUG=1
使用GDB: gdb 程序名称
gdb move
run 或者 r 直接运行
list或者 l 显示10行，再次键入l 再显示10hang
list 1,1000
to list our entire program.
disassemble _start 反汇编程序
use the breakpoint command (or b):
b _start 设置断点
b 行号
info
registers (or i r): 查看寄存器值
step command (or s). 单步调试；
continue (or c), to continue to
the next breakpoint or to the end of the program. c 继续运行至下一个断点，
info breakpoints
(or i b) command； 查看设置的断点, delete 删除某个断点
display memory in different formats, the main command being x. It has
the following format:
x /Nfu addr 显示内存信息
where
• N is the number of objects to display
• f is the display format where some common ones are
• t for binary
• x for hexadecimal
• d for decimal
• i for instruction
• s for string
• u is unit size and is any of
• b for bytes
• h for halfwords (16 bits)
• w for words (32 bits)
• g for giant words (64 bits)
To exit gdb, type q (for quit or type control-d). 退出GDB
交叉编译
sudo apt-get install gcc-aarch64-linux-gnu g++-aarch64-linux-gnu
修改一下 makefile，直接指定编译程序
仿真
如果没有arm64CPU 也可以在intel CPU 的linux下安装qemu来仿真arm CPU
-f 手动指定 makefile；