sfence.vma pseudoinstruction forms are undocumented

[aswaterman]

I'm copying @asb's old issue here riscv/riscv-isa-manual#118

The current GNU tools accept sfence.vma and sfence.vma $rs1 as well as the usual sfence.vma $rs1, $rs2. It's useful for tool authors to know this form exists, and table 20.2 lists a number of pseudoinstruction forms (e.g. fence as shorthand for fence iorw, iorw).

The abbreviated sfence.vma forms aren't documented anywhere currently. Unfortunately it's not clear where that documentation should go, given that table 20.2 is part of the user-level ISA spec and sfence.vma is introduced only in the privileged spec.

[henry-hsieh]

Is there any update of the issue? As my understanding, the missing operand should be assigned to x0. The mapping table is listed below:

Pseudoinstruction	Mapping
sfence.vma	sfence.vma x0, x0
sfence.vma rs1	sfence.vma rs1, x0

Will this be updated to the list?

[henry-hsieh]

In addition to sfence.vma, are the instructions introduced in Svinval extension also having the pseudoinstruction form? The instructions are sinval.vma, hfence.vvma, hfence.gvma, hinval.vvma, and hinval.gvma.