Field Name Bits Default Description ENABLE 0 0x1 Enables tiling, otherwise all tiles receive all polygons. POSSIBLE VALUES: 00 - Tiling disabled. 01 - Tiling enabled (def). PIPE_COUNT 3:1 0x0 Specifies the number of active pipes and contexts (up to 4 pipes, 1 ctx). When this field is written, it is automatically reduced by hardware so as not to use more pipes than the number indicated in GB_PIPE_SELECT.MAX_PIPES or the number of pipes left unmasked GB_PIPE_SELECT.BAD_PIPES. The potentially altered value is read back, rather than the original value written by software. POSSIBLE VALUES: 00 - RV350 (1 pipe, 1 ctx) 03 - R300 (2 pipes, 1 ctx) 06 – R420-3P (3 pipes, 1 ctx) 07 – R420 (4 pipes, 1 ctx) TILE_SIZE 5:4 0x1 Specifies width & height (square), in pixels (only 16, 32 available). POSSIBLE VALUES: 00 - 8 pixels. 01 - 16 pixels. 02 - 32 pixels. SUPER_SIZE 8:6 0x0 Specifies number of tiles and config in super chip configuration. POSSIBLE VALUES: 00 - 1x1 tile (one 1x1). 01 - 2 tiles (two 1x1 : ST-A,B). 02 - 4 tiles (one 2x2). 03 - 8 tiles (two 2x2 : ST-A,B). 04 - 16 tiles (one 4x4). 05 - 32 tiles (two 4x4 : ST-A,B). 06 - 64 tiles (one 8x8). 07 - 128 tiles (two 8x8 : ST-A,B). SUPER_X 11:9 0x0 X Location of chip within super tile. SUPER_Y 14:12 0x0 Y Location of chip within super tile. SUPER_TILE 15 0x0 Tile location of chip in a multi super tile config (Super size of 2,8,32 or 128). POSSIBLE VALUES: 00 - ST-A tile. 01 - ST-B tile. SUBPIXEL 16 0x0 Specifies the precision of subpixels wrt pixels (12 or 16). POSSIBLE VALUES: 00 - Select 1/12 subpixel precision. 01 - Select 1/16 subpixel precision. QUADS_PER_RAS 18:17 0x0 Specifies the number of quads to be sent to each rasterizer in turn when in RV300B or R300B mode POSSIBLE VALUES: 00 - 4 Quads 01 - 8 Quads 02 - 16 Quads 03 - 32 Quads BB_SCAN 19 0x0 Specifies whether to use an intercept or bounding box based calculation for the first (coarse) scan converter POSSIBLE VALUES: 00 - Use intercept based scan converter 01 - Use bounding box based scan converter ALT_SCAN_EN 20 0x0 Specifies whether to use an altenate scan pattern for the coarse scan converter POSSIBLE VALUES: 00 - Use normal left-right scan 01 - Use alternate left-right-left scan ALT_OFFSET 21 0x0 Not used -- should be 0 POSSIBLE VALUES: 00 - Not used 01 - Not used SUBPRECISION 22 0x0 Set to 0 ALT_TILING 23 0x0 Support for 3x2 tiling in 3P mode POSSIBLE VALUES: 00 - Use default tiling in all tiling modes 01 - Use alternative 3x2 tiling in 3P mode Z_EXTENDED 24 0x0 Support for extended setup Z range from [0,1] to [-2,2] with per pixel clamping POSSIBLE VALUES: 00 - Use (24.1) Z format, with vertex clamp to [1.0,0.0] 01 - Use (S25.1) format, with vertex clamp to [2.0,-2.0] and per pixel [1.0,0.0]