ARM NEON汇编器错误:“指令不能是有条件的" [英] ARM NEON assembler error: "instruction cannot be conditional"

查看：184 发布时间：2020/5/6 10:53:25 xcode math assembly arm neon

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根据手臂信息center vadd可以有条件地执行，但是当我尝试

According to the arm info center vadd can be executed condtitionally however when i try

vaddeq.f32 d0,d0,d1

Xcode返回

65:instruction cannot be conditional -- vaddeq.f32 d0,d0,d1

我注意到的一件事是，似乎只有NEON指令会产生此错误. VFP指令不会产生这些错误.

one thing i've noticed is that it seems to be only NEON instructions that give this error. VFP instructions don't produce these errors.

是否需要设置编译器标志才能启用NEON条件指令?

Is there a compiler flag I have to set in order to enable NEON conditional instructions?

《 ARM体系结构参考手册》说:

The ARM Architecture Reference Manual says:

 An ARM Advanced SIMD VADD instruction must be unconditional.

也就是说，如果您处于ARM模式，则这些说明不是有条件的.如果将它们放在IT块中，则可以在Thumb-2中有条件地使用它们.

I.e., if you're in ARM mode, those instructions are not conditional. You can use them conditionally in Thumb-2 if you put them in an IT block.

  .syntax unified
  .code 16
  .globl _foo
_foo:
  cmp r0, #0
  it eq
  vaddeq.f32 d0, d0, d1
  bx lr

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ARM NEON汇编器错误:“指令不能是有条件的" [英] ARM NEON assembler error: &quot;instruction cannot be conditional&quot;