nv2a 0x97 -> 0x09fc (Unknown?) unhandled

[dracc]

Title

https://xemu.app/titles/4d53006e
https://xemu.app/titles/53430007

Bug Description

According to the debug output, 0x97 -> 0x09FC is unhandled.
In the NV20 nouveau sources, this instruction is unknown.

The parameter of the call has so far been observed as one of the following:
0x1

Expected Behavior

The NV2A instruction 0x09FC should be handled.

xemu Version

0.6.2-55-gcaf84884c4

System Information

N/A

Additional Context

No response

[Triticum0]

Also, affect rolling, 0x1
https://xemu.app/titles/53430007/#Rolling

[jackchentwkh]

NV097_SET_FLAT_SHADE_OP 0x000009FC

[abaire]

Test: abaire/nxdk_pgraph_tests@cd1bdae
HW results: https://github.com/abaire/nxdk_pgraph_tests_golden_results/wiki/Results-Shade_model

As can be seen from the HW results, this only seems to affect flat shaded untextured quads. For example:

Set to 0:

Set to 1:

My original PR that fixed the SHADE_MODEL handling can probably be easily extended to address this, since I explicitly had to add handling to cover the "provoking vertex is first" which appears to be the state used by most titles (all of the ones that I happen to have pgraph traces for set this to 1, "first"). See #1086