data_read_text=$(dd if=/dev/mem bs=4 count=1 skip=$(($addr/4)) 2>/dev/null | hexdump -e '/4 "%08x\n"' | sed 's/../& /g')

这段代码的作用是将从`/dev/mem`中读取的4字节数据转换为16进制格式的文本。具体来说：

1. `dd if=/dev/mem bs=4 count=1 skip=$(($addr/4)) 2>/dev/null`从`/dev/mem`中读取4字节数据，并跳过前`$addr`个字节。`2>/dev/null`表示将错误输出重定向到空设备，以避免在屏幕上输出不相关的信息。
2. `hexdump -e '/4 "%08x\n"'`将4字节数据转换为16进制格式的文本，每个字节用8位表示，每行输出一个数字并换行。
3. `sed 's/../& /g'`将每两个字符（即每个字节）之间插入一个空格，以便更好地阅读。

最终的结果是将读取的4字节数据转换为类似于`55 AA 55 AA`的16进制格式的文本。

相关问题

start_addr=0x05877000 #end_addr=0x3ffff000 end_addr=0x05877002 data_write=0x55AA55AA data_read=$(printf "%08x" $data_write) count=0 match_count=0 for ((addr=$start_addr; addr<$end_addr; addr=addr+4)); do echo $data_write | dd of=/dev/mem bs=4 count=1 seek=$(($addr/8)) conv=notrunc 2>/dev/nul done for ((addr=$start_addr; addr<$end_addr; addr+=4)); do data=$(dd if=/dev/mem bs=4 count=1 skip=$(($addr/4)) 2>/dev/null | hexdump -e '/4 "%08x\n"') if [ "$data_read" == "$data" ]; then match_count=$((match_count+1)) fi count=$((count+1)) done echo $data echo $data_read那么该如何修改程序才能让程序输出PASS

为了让程序输出 PASS，我们需要在循环结束后，判断 match_count 是否等于 count，如果等于，即所有数据都成功读取并且与写入的数据一致，就输出 PASS。

修改后的代码如下：

start_addr=0x05877000
end_addr=0x3ffff000
data_write=0x55AA55AA
data_read=$(printf "%08x" $data_write)
count=0
match_count=0

for ((addr=$start_addr; addr<$end_addr; addr=addr+4)); do
    echo $data_write | dd of=/dev/mem bs=4 count=1 seek=$(($addr/8)) conv=notrunc 2>/dev/nul
done

for ((addr=$start_addr; addr<$end_addr; addr+=4)); do
    data=$(dd if=/dev/mem bs=4 count=1 skip=$(($addr/4)) 2>/dev/null | hexdump -e '/4 "%08x\n"')
    if [ "$data_read" == "$data" ]; then
        match_count=$((match_count+1))
    fi
    count=$((count+1))
done

if [ $match_count -eq $count ]; then
    echo "PASS"
else
    echo "FAIL"
fi

echo $data
echo $data_read

这样，当所有数据都成功读取并且与写入的数据一致时，程序就会输出 PASS。

start_addr=0x30000000 end_addr=0x30000003 data_write=0x55AA55AA count=0 match_count=0 # 写入数据 for ((addr=$start_addr; addr<$end_addr+1; addr=addr+1)); do echo "addr: $addr" echo -ne "\x55\xAA\x55\xAA" | dd of=/dev/mem bs=4 count=1 seek=$(($addr/8)) conv=notrunc 2>/dev/null data=$(echo -ne "\x55\xAA\x55\xAA" | hexdump -e '/4 "%08x\n"') data_text=$(echo -ne "\x55\xAA\x55\xAA" | hexdump -e '/4 "%08x\n"' | sed 's/../& /g') echo "data_text: $data_text" #echo "data: $data" data_read=$(dd if=/dev/mem bs=4 count=1 skip=$(($addr/4)) 2>/dev/null | hexdump -e '/4 "%08x\n"') data_read_text=$(dd if=/dev/mem bs=4 count=1 skip=$(($addr/4)) 2>/dev/null | hexdump -e '/4 "%08x\n"' | sed 's/../& /g') echo "data_read_text: $data_read_text" # echo "data_read: $data_read" if [ "$data_read" == "$data" ]; then match_count=$((match_count+1)) echo "match_count: $match_count" fi count=$((count+1)) echo "count: $count" done # 输出结果 # 判断结果 if [ $match_count -eq $count ]; then echo "PASS" else echo "FAIL" fi如何能让这段代码输出addr时输出0x30000000、0x30000001、0x30000002和0x30000003而不是805306368、805306369、805306370和805306371

可以使用printf命令来控制输出格式，将addr以16进制的形式输出。修改代码如下：

start_addr=0x30000000
end_addr=0x30000003
data_write=0x55AA55AA
count=0
match_count=0

# 写入数据
for ((addr=$start_addr; addr<$end_addr+1; addr=addr+1)); do
    printf "addr: 0x%x\n" $addr
    echo -ne "\x55\xAA\x55\xAA" | dd of=/dev/mem bs=4 count=1 seek=$(($addr/8)) conv=notrunc 2>/dev/null
    data=$(echo -ne "\x55\xAA\x55\xAA" | hexdump -e '/4 "%08x\n"')
    data_text=$(echo -ne "\x55\xAA\x55\xAA" | hexdump -e '/4 "%08x\n"' | sed 's/../& /g')
    echo "data_text: $data_text"
    #echo "data: $data"

    data_read=$(dd if=/dev/mem bs=4 count=1 skip=$(($addr/4)) 2>/dev/null | hexdump -e '/4 "%08x\n"')
    data_read_text=$(dd if=/dev/mem bs=4 count=1 skip=$(($addr/4)) 2>/dev/null | hexdump -e '/4 "%08x\n"' | sed 's/../& /g')
    echo "data_read_text: $data_read_text"
    #echo "data_read: $data_read"

    if [ "$data_read" == "$data" ]; then
        match_count=$((match_count+1))
        echo "match_count: $match_count"
    fi
    count=$((count+1))
    echo "count: $count"
done

# 输出结果

# 判断结果
if [ $match_count -eq $count ]; then
    echo "PASS"
else
    echo "FAIL"
fi

这样输出的addr就会以16进制的形式显示。