thumb-2指令的W后缀是什么意思? [英] What's the meaning of W suffix for thumb-2 instruction?

问题描述

thumb-2 指令有一个 w 后缀，如下所示，如果没有它，它如何改变指令的语义?搜索结果很吵，我没有得到答案.

There is a w suffix for thumb-2 instruction as below, how does it change the semantic of the instruction without it? The search result is very noisy and I didn't get the answer.

addw r0, r1, #0

推荐答案

我在 Cortex-M3 TRM 表 2-5

Data operations with large immediate
ADDW and SUBW have a 12-bit immediate. This means they can replace many from memory literal loads.

快速参考

add wide T2 ADD Rd, Rn, #<imm12>

看起来汇编器会识别直接常量 <= 12 位，并执行必要的操作.

Looks like the assembler would recognize the immediate constant <= 12 bits, and do the needful.

在你看到的上下文中，它是一个普通的添加".

In the context where you see it, it is an ordinary "add".

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