c - .c 文件中的内联 PPC 汇编代码出现 "Error: unsupported relocation against <register>"错误

Question

我有下面的内联汇编代码。但是当我尝试编译它时，它抛出代码片段后提到的错误。

unsigned int func(void)
{
  __asm__ ("mfspr r3, svr;");
}

以下是错误。

{standard input}: Assembler messages:
{standard input}:3349: Error: unsupported relocation against r3
{standard input}:3349: Error: unsupported relocation against svr
{standard input}:3375: Error: unsupported relocation against r3
{standard input}:3375: Error: unsupported relocation against svr
{standard input}:3510: Error: unsupported relocation against r3
{standard input}:3510: Error: unsupported relocation against svr
{standard input}:3517: Error: unsupported relocation against r3
{standard input}:3517: Error: unsupported relocation against svr

谁能帮我解决这些问题？

Answer 1

显然 gas 没有对这些寄存器的内置支持。为了使用它们，您应该自己定义它们或明确使用它们的索引，例如:

mfspr 3, <some_index_here>

或者您可以包括:ppc_asm.tmpl .

如果您的核心是 e500那么 svr 索引将为 1023。