《Programming from the Ground Up》学习第 8 天，p117-p146 总结，总计 30 页。
一、技术总结
1.共享函数用法示例
(1)不使用共享函数
linux.s：
# filename:linux.s
# system call numbers(按数字大小排列，方便查看).equ SYS_READ, 0.equ SYS_WRITE, 1.equ SYS_OPEN, 2.equ SYS_CLOSE, 3.equ SYS_EXIT, 60
# standard file descriptors.equ STDIN, 0.equ STDOUT, 1.equ STDERR, 2
# common status codes.equ END_OF_FILE, 0
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helloworld-nolib.s：
#filename: helloworld-nolib.s# 编译命令： # as helloworld-nolib.s -o helloworld-nolib.o # ld helloworld-nolib.o -o helloworld-lib.include "linux.s"
.section .datahelloworld: .ascii "hello world\n"helloworld_end: #helloworld_end - helloworld的意思： .equ helloworld_len, helloworld_end - helloworld.section .text .global _start
_start: #write涉及到SYS_WRITE， movq $SYS_WRITE, %rax movq $STDOUT, %rdi movq $helloworld, %rsi movq $helloworld_len, %rdx syscall # 退出函数: exit() movq $SYS_EXIT, %rax movq $0, %rdi syscall
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执行 helloworld-nolib 结果：
# ./helloworld-nolibhello world
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(2)使用共享函数：print、exit
helloworld-lib.s:
# filename: helloworld-lib.s# 编译命令： # as helloworld-lib.s -o helloworld-lib.o # ld -dynamic-linker /lib64/ld-linux-x86-64.so.2 -o helloworld-lib helloworld-lib.o -lc.section .datahelloworld: .ascii "hello world\n\0"
.section .text .globl _start _start: movq $helloworld, %rdi call printf # C语言中的printf movq $0, %rdi call exit # C语言中的exit
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执行 helloworld-lib 结果：
# ./helloworld-nolibhello world
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2.问题：-bash: ./helloworld-lib: No such file or directory
root@LAPTOP-5PGRQ2IO:/mnt/d/Projects/AssemblyProjects# ld -dynamic-linker /lib/ld-linux.so.2 -o helloworld-lib helloworld-lib.o -lc root@LAPTOP-5PGRQ2IO:/mnt/d/Projects/AssemblyProjects# ll total 96 drwxrwxrwx 1 root root 4096 Sep 28 15:48 ./ drwxrwxrwx 1 root root 4096 Jun 24 07:23 ../ -rwxrwxrwx 1 root root 147 Aug 25 16:18 add-year.s* -rwxrwxrwx 1 root root 1075 Aug 31 18:55 count-chars.s* -rwxrwxrwx 1 root root 112 Aug 25 16:26 error-exit.s* -rwxrwxrwx 1 root root 863 Jul 1 23:39 exit.s* -rwxrwxrwx 1 root root 14048 Sep 28 15:48 helloworld-lib* -rwxrwxrwx 1 root root 920 Sep 28 15:47 helloworld-lib.o* -rwxrwxrwx 1 root root 224 Sep 2 08:43 helloworld-lib.s* -rwxrwxrwx 1 root root 9224 Sep 28 15:44 helloworld-nolib* -rwxrwxrwx 1 root root 1208 Sep 2 08:39 helloworld-nolib.o* -rwxrwxrwx 1 root root 510 Sep 2 08:39 helloworld-nolib.s* -rwxrwxrwx 1 root root 264 Aug 24 17:52 linux.s* -rwxrwxrwx 1 root root 774 Jul 3 06:25 maximum.s* drwxrwxrwx 1 root root 4096 Aug 25 16:20 pgu_64-master/ -rwxrwxrwx 1 root root 2318 Jul 16 07:52 power.s* -rwxrwxrwx 1 root root 453 Aug 24 18:14 read-record.s* -rwxrwxrwx 1 root root 1333 Aug 24 18:15 read-records.s* -rwxrwxrwx 1 root root 117 Aug 23 08:23 record-def.s* -rwxrwxrwx 1 root root 984 Aug 24 17:58 test.dat* -rwxrwxrwx 1 root root 5612 Jul 27 11:47 toupper.s* -rwxrwxrwx 1 root root 1128 Aug 24 17:57 write-record.o* -rwxrwxrwx 1 root root 686 Aug 24 17:54 write-record.s* -rwxrwxrwx 1 root root 10816 Aug 24 17:58 write-records* -rwxrwxrwx 1 root root 2632 Aug 24 17:57 write-records.o* -rwxrwxrwx 1 root root 2081 Aug 24 17:57 write-records.s* root@LAPTOP-5PGRQ2IO:/mnt/d/Projects/AssemblyProjects# ./helloworld-lib -bash: ./helloworld-lib: No such file or directory
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在执行 ./helloworld-lib 命令时提示 -bash: ./helloworld-lib: No such file or directory，但 helloworld-lib 实际上是存在的。
# ls /lib/ld-linux.so.2 ls: cannot access '/lib/ld-linux.so.2': No such file or directory
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执行 ls /lib/ld-linux.so.2 命令可以发现系统中没有 /lib/ld-linux.so.2 这个文件，所以虽然执行 ld 命令时没有报错，但是执行 ./helloworld-lib 命令时报错了：-bash: ./helloworld-lib: No such file or directory。
ld -dynamic-linker /lib64/ld-linux-x86-64.so.2 -o helloworld-lib helloworld-lib.o -lc
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二、英语总结
1.majorly
p129, Code that is copied often has to be majorly modified to fit the surrounding code.在这里，majorly 既可以指“量”也可以指“质”上的巨大修改。
三、其它
上一次阅读还是 2024/8/24，期间因为工作上一些不愉快的事一直没有抽离出来，今天算是慢慢调整过来了，继续干。
四、参考资料
1. 编程
(1)Jonathan Bartlett，《Programming From The Ground Up》：https://book.douban.com/subject/1787855/
2. 英语
(1)Etymology Dictionary：https://www.etymonline.com
(2) Cambridge Dictionary：https://dictionary.cambridge.org
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