slt

Compares sources to see which source is less. Sets the destination to 1.0 if the first source operand is less than the second source operand; otherwise, the destination is set to 0.0.

slt dest, src0, src1

Registers

dest

Destination register.

src0

Input source register.

src1

Input source register.

To learn more about registers, see Registers.

Remarks

The following code fragment shows the operations performed by the slt instruction.

dest.x = (src0.x < src1.x) ? 1.0f : 0.0f;
dest.y = (src0.y < src1.y) ? 1.0f : 0.0f;
dest.z = (src0.z < src1.z) ? 1.0f : 0.0f;
dest.w = (src0.w < src1.w) ? 1.0f : 0.0f;

Example

// The following example compares the component color values of the two sources.

vs.1.0
m4x4 oPos, v0, c0	; transform vertices by view/projection matrix

mov r0, c5		    ; load pink
slt r2, c4, r0		    ; compare green to pink
mov oD0, r2		    ; output result

// The resultant vertex color is red (1, 0, 0) and is shown below. The red 
// component is 1 because src0.x > src1.x. The green component is 0 
// because src0.y < src1.y and the blue component is 0 because 
// src0.z < src1.z.

// Additional code is used to initialize the constant registers.

D3DXMATRIX mat, matView, matProj;
D3DXMatrixMultiply(&mat, &matView, &matProj);
D3DXMatrixTranspose(&mat, &mat);
// set C0 with the view and projection matrix
m_pd3dDevice->SetVertexShaderConstant(0, &mat, 4);

// set register C4
float colorGreen[] = {0, 1, 0, 0};
m_pd3dDevice->SetVertexShaderConstant(4, &colorGreen, 1);

// set register C5
float colorPink[] = {0.75, 0, 0, 0};
m_pd3dDevice->SetVertexShaderConstant(5, &colorPink, 1);

// The first SetVertexShaderConstant method binds the C0 register 
// with the first row of the view/projection matrix (rows 2, 3 and 4 are 
// bound to registers C2, C3 and c4 also). The m4x4 instruction 
// (in the shader file) loads the data.


// The second SetVertexShaderConstant method binds the C4 register 
// with data for the color green. The last SetVertexShaderConstant 
// method binds the C5 register with data for the color pink.