冒号在此ARM NEON代码中的含义是什么

Question

我正在重构一些ARM汇编代码,我发现了这两条指令,但我不明白它们的含义.加载和存储操作在基地址注册后有一个冒号,我在文档中找不到任何内容:

vld4.8      {d0-d3}, [r1,:256]!
vst1.8      {q12}, [r0,:128]!

有谁知道在哪里可以找到所有可能的操作和参数组合的完整文档？

Answer 1

这是一个地址对齐限定符:

9.4.2.5 NEON Alignment Specifiers

Some NEON load/store instructions allow an optional address alignment
qualifier. The ARM documentation specifies that this is indicated by `@
align'. However GAS already interprets the `@' character as a "line comment"
start, so `: align' is used instead. For example:

             vld1.8 {q0}, [r0, :128]