Microsoft DirectX 8.0 (C++)

Input Registers

The following table lists the minimum available input registers for use by a Microsoft® DirectX® 8.0 vertex shader. Note that this table applies to version 1.0 pixel shaders.

Name Count I/O Permissions Number Allowed per Instruction
an 1 scalar write/use only 0 in version 1.0; 1 in version 1.1
c[n] 96 vectors read-only 1
rn 12 vectors read/write 3
vn 16 vectors read-only 1