asm.rules.stack-below-sp is ambiguous

Stacks can grow in different directions and diagrams can be top-to-bottom or bottom-to-top.
Apparently the SPARC arch can select whether the stack grows up or down.

This section of the reference talks about stack space below the stack pointer, but because of different models of how stacks can work, it's not entirely clear what that means.

• If the text is meant 'by address', then the rule changes based on the arch
• If the text is meant logically, then it should probably say so. And it should still specify the direction.

Instead of up and down, maybe it should be specified in terms of 'used' vs 'potential' stack? Or 'active' and 'inactive'?

Or maybe describe the contents you're allowed to interact with. For example, are you allowed to read the stack frame of the caller of the current function?

The more I read the current text, the less I'm sure what it actually says.

Start with the Rust Reference inline-assembly section linked in the issue, especially the rule named asm.rules.stack-below-sp, and compare its wording with the SPARC stack-direction behavior mentioned. Clarify whether the rule is address-based or logical, specify the relevant direction or stack region, and ensure the resulting text explains what stack contents may be accessed.