cmp - ps

Choose src1 if src0 >= 0. Otherwise, choose src2. The comparison is done per channel.

Syntax

cmp dst, src0, src1, src2

 

where

• dst is the destination register.
• src0 is a source register.
• src1 is a source register.
• src2 is a source register.

Remarks

Pixel shader versions	1_1	1_2	1_3	1_4	2_0	2_x	2_sw	3_0	3_sw
cmp		x	x	x	x	x	x	x	x

 

There are a few additional limitations for versions 1_2 and 1_3:

• Each shader can use up to a maximum of three cmp instructions.
• The destination register cannot be the same as any of the source registers.

This example does a four-channel comparison.

ps_1_4
def c0, -0.6, 0.6, 0, 0.6
def c1  0,0,0,0
def c2  1,1,1,1

mov r1, c1
mov r2, c2

cmp r0, c0, r1, r2   // r0 is assigned 1,0,0,0 based on the following:

// r0.x = c2.x because c0.x < 0
// r0.y = c1.y because c0.y >= 0
// r0.z = c1.z because c0.z >= 0
// r0.w = c1.w because c0.w >= 0

Related topics

Pixel Shader Instructions