芯片架构_地址线位宽和地址空间的进制转换方法
作者：jason-wrj
分类：芯片架构
标签：芯片架构，DSP，ARM，MCU，MPU，嵌入式操作系统，操作系统
更多：www.dioit.com——迪欧IT——嵌入式电子智能技术
一、地址线位宽，换算最大地址空间
地址线位宽n，计算2的n次幂，得出最大地址空间大小，如下表所示：
| 地址线位宽n，2的n次幂 | 十六进制 | 空间大小 | 十进制 |
|---|---|---|---|
| (04位地址线 => 2^4 ) 0xF + 1 | => 0x10 | => 16B | |
| (08位地址线 => 2^8 ) 0xFF + 1 | => 0x100 | => 256B | |
| (12位地址线 => 2^12 ) 0xFFF + 1 | => 0x1000 | => 4KB | => 4096 / 1024 |
| (16位地址线 => 2^16 ) 0xFFFF + 1 | => 0x1 0000 | => 64KB | => 65536 / 1024 |
| (20位地址线 => 2^20 ) 0xF FFFF + 1 | => 0x10 0000 | => 1MB | => 1048576 / 1024 / 1024 |
| (24位地址线 => 2^24 ) 0xFF FFFF + 1 | => 0x100 0000 | => 16MB | => 16777216 / 1024 / 1024 |
| (28位地址线 => 2^28 ) 0xFFF FFFF + 1 | => 0x1000 0000 | => 256MB | => 268435456 / 1024 / 1024 |
| (32位地址线 => 2^32 ) 0xFFFF FFFF + 1 | => 0x1 0000 0000 | => 4GB | => 4294967296 / 1024 / 1024 / 1024 |
二、十六进制，换算地址线位宽和最大地址空间
十六进制数，先换成二进制数，首位1后面还有n个0，地址线位宽就需要n根地址线。
最大地址空间就是2的n次幂字节，如下表所示：
| 十六进制 | 十进制 | 空间大小 |
|---|---|---|
| 0x10 | => 16 | = 16B |
| 0x100 | => 256 | = 256B |
| 0x400 | => 1024 | = 1KB |
| 0x800 | => 2048 | = 2KB |
| 0xC00 | => 3072 | = 3KB |
| 0x1000 | => 4096 | = 4KB |
| 0x4000 | => 16384 | = 16KB |
| 0x8000 | => 32768 | = 32KB |
| 0xC000 | => 49152 | = 48KB |
| 0x1 0000 | => 65536 | = 64KB |
| 0x4 0000 | => 262144 | = 256KB |
| 0x8 0000 | => 524288 | = 512KB |
| 0xC 0000 | => 786432 | = 768KB |
| 0x10 0000 | => 1048576 | = 1MB |
| 0x40 0000 | => 4194304 | = 4MB |
| 0x80 0000 | => 8388608 | = 8MB |
| 0xC0 0000 | => 12582912 | = 12MB |
| 0x100 0000 | => 16777216 | = 16MB |
| 0x400 0000 | => 67108864 | = 64MB |
| 0x800 0000 | => 134217728 | = 128MB |
| 0xC00 0000 | => 201326592 | = 192MB |
| 0x1000 0000 | => 268435456 | = 256MB |
| 0x4000 0000 | => 1073741824 | = 1GB |
| 0x8000 0000 | => 2147483648 | = 2GB |
| 0xC000 0000 | => 3221225472 | = 3GB |
| 0x1 0000 0000 | => 4294967296 | = 4GB |
三、地址线位宽，快速换算最大地址空间的字节单位
地址线位宽n，计算出2的n次幂，逢10进一个字节单位，即乘以1024，如下表所示：
常见字节单位：
1B (Byte)，1KB (Kilo) ，1MB (Meg)，1GB (Giga)，1TB (Tera)，1PB (Peta)，1EB (Exa)，1ZB (Zetta)，1YB (Yotta)
技巧： 2^32可以分成 2^10 2^10 2^10 2^2 = 1024 1024 1024 4 = 4GB
| n次幂 | 十进制数 | 地址空间大小 |
|---|---|---|
| 2^0 | = 1 | => 1B |
| 2^1 | = 2 | => 2B |
| 2^2 | = 4 | => 4B |
| 2^3 | = 8 | => 8B |
| 2^4 | = 16 | => 16B |
| 2^5 | = 32 | => 32B |
| 2^6 | = 64 | => 64B |
| 2^7 | = 128 | => 128B |
| 2^8 | = 256 | => 256B |
| 2^9 | = 512 | => 512B |
| 2^10 | = 1024 | => 1KB (Kilo) |
| 2^16 | = 65536 | => 64KB |
| 2^20 | = 1048576 | => 1MB (Meg) |
| 2^24 | = 16777216 | => 16MB |
| 2^30 | = 1073741824 | => 1GB (Giga) |
| 2^32 | = 4294967296 | => 4GB |
| 2^40 | = 1099511627776 | => 1TB (Tera) |
| 2^50 | = 1125899906842624 | => 1PB (Peta) |
| 2^60 | = 1152921504606846976 | => 1EB (Exa) |
| 2^64 | = 18446744073709551616 | => 16EB |
| 2^70 | = 1180591620717411303424 | => 1ZB (Zetta) |
| 2^80 | = 1208925819614629174706176 | => 1YB (Yotta) |
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