Text and description quoted verbatim from Microsoft DirectX 7 help file, included here for convenient reference.

The D3DTEXTUREADDRESS enumerated type describes the supported texture-addressing modes when setting them with the D3DTSS_ADDRESS, D3DTSS_ADDRESSU, and D3DTSS_ADDRESSV texture-stage states.

typedef enum _D3DTEXTUREADDRESS {
D3DTADDRESS_WRAP = 1,
D3DTADDRESS_MIRROR = 2,
D3DTADDRESS_CLAMP = 3,
D3DTADDRESS_BORDER = 4,
D3DTADDRESS_FORCE_DWORD = 0x7fffffff,
} D3DTEXTUREADDRESS;

D3DTADDRESS_WRAP
Tile the texture at every integer junction. For example, for u values between 0 and 3, the texture is repeated three times; no mirroring is performed.
D3DTADDRESS_MIRROR
Similar to D3DTADDRESS_WRAP, except that the texture is flipped at every integer junction. For u values between 0 and 1, for example, the texture is addressed normally; between 1 and 2, the texture is flipped (mirrored); between 2 and 3, the texture is normal again, and so on.
D3DTADDRESS_CLAMP
Texture coordinates outside the range [0.0, 1.0] are set to the texture color at 0.0 or 1.0, respectively.
D3DTADDRESS_BORDER
Texture coordinates outside the range [0.0, 1.0] are set to the border color, which is a new render state corresponding to D3DRENDERSTATE_BORDERCOLOR in the D3DRENDERSTATETYPE enumerated type.
D3DTADDRESS_FORCE_DWORD
Forces this enumeration to compile to 32 bits in size. This value is not used.
Remarks
For information about using the D3DRENDERSTATE_WRAPU and D3DRENDERSTATE_WRAPV render states, see Textures.