r300/compiler: add a function for swizzling a mask

2 files changed, 15 insertions, 6 deletions

diff --git a/src/mesa/drivers/dri/r300/compiler/radeon_optimize.c b/src/mesa/drivers/dri/r300/compiler/radeon_optimize.c
index 27b10ffbd6..44f4c0fbdc 100644
--- a/src/mesa/drivers/dri/r300/compiler/radeon_optimize.c
+++ b/src/mesa/drivers/dri/r300/compiler/radeon_optimize.c
@@ -54,12 +54,7 @@ static struct rc_src_register chain_srcregs(struct rc_src_register outer, struct
 		combine.Negate = outer.Negate;
 	} else {
 		combine.Abs = inner.Abs;
-		combine.Negate = 0;
-		for(unsigned int chan = 0; chan < 4; ++chan) {
-			unsigned int swz = GET_SWZ(outer.Swizzle, chan);
-			if (swz < 4)
-				combine.Negate |= GET_BIT(inner.Negate, swz) << chan;
-		}
+		combine.Negate = swizzle_mask(outer.Swizzle, inner.Negate);
 		combine.Negate ^= outer.Negate;
 	}
 	combine.Swizzle = combine_swizzles(inner.Swizzle, outer.Swizzle);
diff --git a/src/mesa/drivers/dri/r300/compiler/radeon_program.h b/src/mesa/drivers/dri/r300/compiler/radeon_program.h
index 913815b24d..772ea14df3 100644
--- a/src/mesa/drivers/dri/r300/compiler/radeon_program.h
+++ b/src/mesa/drivers/dri/r300/compiler/radeon_program.h
@@ -204,6 +204,20 @@ static inline rc_swizzle rc_mask_to_swizzle(unsigned int mask)
 	}
 	return RC_SWIZZLE_UNUSED;
 }
+
+/* Reorder mask bits according to swizzle. */
+static inline unsigned swizzle_mask(unsigned swizzle, unsigned mask)
+{
+	unsigned ret = 0;
+	for (unsigned chan = 0; chan < 4; ++chan) {
+		unsigned swz = GET_SWZ(swizzle, chan);
+		if (swz < 4)
+			ret |= GET_BIT(mask, swz) << chan;
+	}
+	return ret;
+}
+
+
 struct rc_src_register lmul_swizzle(unsigned int swizzle, struct rc_src_register srcreg);
 
 static inline void reset_srcreg(struct rc_src_register* reg)