.cspec file manual

[netwarfire]

I found one manual about Compiler Specification in https://spinsel.dev/assets/2020-06-17-ghidra-brainfuck-processor-1/ghidra_docs/compiler_spec/index.html, this is old, there is no in this manual, and I cannot find in ghihub, who can help me?

[netwarfire]

I want to find some document about the tag rule, such as



<datatype_at index="1">

</datatype_at>

<consume_extra storage="general"/>
<consume_extra storage="general"/>

what is the meanning!

[xop01]

There's no newer HTML tag manual for this. The spinsel page you found is the old compiler-spec docs (<pentry>, stack, etc.). <datatype_at> / <consume_extra> came later as <rule> language inside <prototype>, and they're documented in source comments, mainly modelrules.hh, plus a real example in mips32le.cspec.

A <rule> is just: if this parameter matches X, put it here, and maybe skip some other registers. <datatype_at index="1"> is a condition, not storage. It looks at another argument (0 = first, 1 = second) and the rule only fires if that one matches the inner <datatype>. The current parameter is still described by the sibling <datatype> / <position>.

<consume_extra storage="general"/> is a side effect. It does not assign the current param. After the real assign (<consume storage="float"/> etc.) it marks unused GPRs as already used so later args skip them. By default it burns enough integer regs to cover the current type's size; two of those tags = two extra GPR slots. That's the MIPS "float then double leaves a hole in the integer argument registers" case.