/* * The programmable vertex shader unit has a memory bank of unknown size * that can be written to in 16 byte units by writing the address into * UPLOAD_ADDRESS, followed by data in UPLOAD_DATA (multiples of 4 DWORDs). * * Pointers into the memory bank are always in multiples of 16 bytes. * * The memory bank is divided into areas with fixed meaning. * * Starting at address UPLOAD_PROGRAM: Vertex program instructions. * Native limits reported by drivers from ATI suggest size 256 (i.e. 4KB), * whereas the difference between known addresses suggests size 512. * * Starting at address UPLOAD_PARAMETERS: Vertex program parameters. * Native reported limits and the VPI layout suggest size 256, whereas * difference between known addresses suggests size 512. * * At address UPLOAD_POINTSIZE is a vector (0, 0, ps, 0), where ps is the * floating point pointsize. The exact purpose of this state is uncertain, * as there is also the R300_RE_POINTSIZE register. * * Multiple vertex programs and parameter sets can be loaded at once, * which could explain the size discrepancy. */