Field Name             Bits   Default   Description
ZFUNC                  2:0    0x0       Specifies the Z function.
                                        POSSIBLE VALUES:
                                        00 - Never
                                        01 - Less
                                        02 - Less or Equal
                                        03 - Equal
                                        04 - Greater or Equal
                                        05 - Greater Than
                                        06 - Not Equal
                                        07 - Always
STENCILFUNC            5:3    0x0       Specifies the stencil function.
                                        POSSIBLE VALUES:
                                        00 - Never
                                        01 - Less
                                        02 - Less or Equal
                                        03 - Equal
                                        04 - Greater or Equal
                                        05 - Greater
                                        06 - Not Equal
                                        07 - Always
STENCILFAIL            8:6    0x0       Specifies the stencil value to be written if the stencil test
                                        fails.
                                        POSSIBLE VALUES:
                                        00 - Keep: New value = Old value
                                        01 - Zero: New value = 0
                                        02 - Replace: New value = STENCILREF
                                        03 - Increment: New value++ (clamp)
                                        04 - Decrement: New value-- (clamp)
                                        05 - Invert new value: New value = !Old value
                                        06 - Increment: New value++ (wrap)
                                        07 - Decrement: New value-- (wrap)
STENCILZPASS           11:9   0x0       Same encoding as STENCILFAIL. Specifies the stencil
                                        value to be written if the stencil test passes and the Z test
                                        passes (or is not enabled).
STENCILZFAIL           14:12  0x0       Same encoding as STENCILFAIL. Specifies the stencil
                                        value to be written if the stencil test passes and the Z test
                                        fails.
STENCILFUNC_BF         17:15  0x0       Same encoding as STENCILFUNC. Specifies the stencil
                                        function for back faced quads , if
                                        STENCIL_FRONT_BACK = 1.
STENCILFAIL_BF         20:18  0x0       Same encoding as STENCILFAIL. Specifies the stencil
                                        value to be written if the stencil test fails for back faced
                                        quads, if STENCIL_FRONT_BACK = 1
STENCILZPASS_BF        23:21  0x0       Same encoding as STENCILFAIL. Specifies the stencil
                                        value to be written if the stencil test passes and the Z test
                                        passes (or is not enabled) for back faced quads, if
                                        STENCIL_FRONT_BACK = 1
STENCILZFAIL_BF        26:24  0x0       Same encoding as STENCILFAIL. Specifies the stencil
                                        value to be written if the stencil test passes and the Z test
                                        fails for back faced quads, if STENCIL_FRONT_BACK=1
ZERO_OUTPUT_MASK       27     0x0       Zeroes the zb coverage mask output. This does not affect
                                        the updating of the depth or stencil values.
                                        POSSIBLE VALUES:
                                        00 - Disable
                                        01 - Enable
