Registers - vs_3_0

This section contains reference information for the input and output registers implemented by vertex shader version 3_0.

Input Registers

Register Name Count R/W # Read ports # Reads / inst Dimension RelAddr Defaults Requires DCL
v# Input Register 16 R 1 Unlimited 4 No See note 1 Yes
r# Temporary Register 32 R/W 3 Unlimited 4 No None No
c# Constant Float Register See note 2 R 1 Unlimited 4 a0 / aL (0, 0, 0, 0) No
a0 Address Register 1 R/W 1 Unlimited 4 No None No
b# Constant Boolean Register 16 R 1 1 1 No FALSE No
i# Constant Integer Register 16 R 1 1 4 No (0, 0, 0, 0) No
aL Loop Counter Register 1 R 1 Unlimited 1 No None No
p0 Predicate Register 1 R/W 1 1 4 no none no
s# Sampler 4 R 1 1 4 No See note 3 Yes

Notes:

  1. Partial (0, 0, 0, 1) - If only a subset of channels are updated, the remaining channels will default to (0, 0, 0, 1).
  2. Equal to D3DCAPS9.MaxVertexShaderConst (at least 256 for vs_3_0).
  3. Defaults for sampler lookup exist, but values depend on texture format.

Output Registers

Output registers have been collapsed into 12 o# (output) registers. These can be used for anything the user wants to interpolate for the pixel shader: texture coordinates, colors, fog, etc.

Register Name Count R/W Dimension RelAddr Defaults Requires DCL
o# Output Register 12 W 4 aL None Yes