time as a systemcall example

• 编译

gcc -o time-asm time-asm.c
gcc -o time time.c
# 64位机器上编出32位代码需加-m32
sudo apt-get install gcc-multilib
gcc -o time time.c -m32

• 反汇编

gcc -o time time.c -static
objdump -S time > time64.S
# 64位机器上编出32位代码需加-m32
sudo apt-get install gcc-multilib
gcc -o time time.c -static -m32
objdump -S time > time32.S