Report the 8-byte GS primitive payload when the shader's context registers
set SPI_SHADER_IDX_FORMAT.IDX0_EXPORT_FORMAT to SPI_SHADER_2COMP, and 0
otherwise. The search runs over every context register, so an earlier
SPI_SHADER_IDX_FORMAT entry with another format does not end it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
winstrex