UC知道这段话怎么翻译啊？计算机外语，与指令集有关
来源：百度知道 编辑：UC知道 时间：2024/07/05 07:14:55
THUMB was introduced in architecture v4T. It is a 16-bit sub-set of the ARM instruction set, designed to resolve the common RISC issue of poor code density with instructions that are all 32 bits. By using a 16-bit encoding scheme, THUMB compiled code is approximately 70% of the size of the ARM equivalent, but it needs 25% more instructions to do the
same task. THUMB and ARM code can inter-work on the same system, using the BLX instruction to switch mode.
Most code in Symbian OS is compiled as THUMB, since the size of the ROM is intimately linked to the cost of a Symbian OS phone. The kernel is built for ARM for increased performance and it requires instructions which are missing from THUMB, such as coprocessor instructions needed to access the MMUand CPU state control registers. Application code can be built for ARM by adding ALWAYS_BUILD_AS_ARM into the application’s MMP file. Symbian does this for algorithmic code, since, for example, the JPEG decoder runs 30% faster when
same task. THUMB and ARM code can inter-work on the same system, using the BLX instruction to switch mode.
Most code in Symbian OS is compiled as THUMB, since the size of the ROM is intimately linked to the cost of a Symbian OS phone. The kernel is built for ARM for increased performance and it requires instructions which are missing from THUMB, such as coprocessor instructions needed to access the MMUand CPU state control registers. Application code can be built for ARM by adding ALWAYS_BUILD_AS_ARM into the application’s MMP file. Symbian does this for algorithmic code, since, for example, the JPEG decoder runs 30% faster when
THUMB是在v4T结构中被引进的。它是ARM指令集的16位子集，被设计出来以解决全32位指令的恶劣代码密度的共同RISC问题。通过使用16位解码方案，THUMB编译的代码大约只相当于ARM的70%，但它只需要另外25%的代码去完成这项工作。使用BLX指令进行模式转换，THUMB和ARM代码可以在同一个系统上相互作用。