> how much work would have been involved in getting this release open sourced
Close to no actual effort (the headers are autogenerated). However there was probably a lot of work behind the scenes with their legal team/whatever to clear the release.
About the shader ISA, I wish I knew. It's certain that the documentation exists, because they provide it to some developers (I've been told the Maxwell ISA docs are part of the Nintendo Switch SDK), so it's not like they have to write it from scratch.
And AMD provides full docs about it [1] (not sure about Intel), so I don't see how it could provide a significant edge over their competition. Maybe raytracing instructions? But for a motivated reverse engineer this stuff isn't impossible to figure out. I think it's down to company culture and inertia.
I don't know about Arc, but Intel has historically probably been the most open with their GPU docs. AMD's is (while laudable, particularly compared to Nvidia) unfortunately a bit of a autogenned dump without context. Where as Intel's is closer to what I expect out of decent SoC documentation; it'll be about half prose explaining the why(!!), and half the autogenned tables of registers and opcode formats.
AMD's approach seems to be documentation in the style you describe plus employed FOSS developers who get access to internal people, simulators, possibly even source code. Makes it annoying for externals to try to contribute code, but the drivers are good.
Close to no actual effort (the headers are autogenerated). However there was probably a lot of work behind the scenes with their legal team/whatever to clear the release.
About the shader ISA, I wish I knew. It's certain that the documentation exists, because they provide it to some developers (I've been told the Maxwell ISA docs are part of the Nintendo Switch SDK), so it's not like they have to write it from scratch.
And AMD provides full docs about it [1] (not sure about Intel), so I don't see how it could provide a significant edge over their competition. Maybe raytracing instructions? But for a motivated reverse engineer this stuff isn't impossible to figure out. I think it's down to company culture and inertia.
[1] https://developer.amd.com/wp-content/resources/RDNA2_Shader_...