From: Eric Anholt <eric@anholt.net>
Date: Wed, 10 Mar 2010 23:32:05 +0000 (-0800)
Subject: i965: Use the SEL instruction to implement MIN and MAX.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=ba541b0769768ffa09562938d3b49690669948b8;p=mesa.git

i965: Use the SEL instruction to implement MIN and MAX.

Saves an instruction over doing conditional moves.
---

diff --git a/src/mesa/drivers/dri/i965/brw_wm_emit.c b/src/mesa/drivers/dri/i965/brw_wm_emit.c
index 412e09b76a1..b1695760174 100644
--- a/src/mesa/drivers/dri/i965/brw_wm_emit.c
+++ b/src/mesa/drivers/dri/i965/brw_wm_emit.c
@@ -633,14 +633,10 @@ void emit_max(struct brw_compile *p,
 
    for (i = 0; i < 4; i++) {
       if (mask & (1<<i)) {	
-	 brw_set_saturate(p, (mask & SATURATE) ? 1 : 0);
-	 brw_MOV(p, dst[i], arg0[i]);
-	 brw_set_saturate(p, 0);
-
-	 brw_CMP(p, brw_null_reg(), BRW_CONDITIONAL_L, arg0[i], arg1[i]);
+	 brw_CMP(p, brw_null_reg(), BRW_CONDITIONAL_GE, arg0[i], arg1[i]);
 
 	 brw_set_saturate(p, (mask & SATURATE) ? 1 : 0);
-	 brw_MOV(p, dst[i], arg1[i]);
+	 brw_SEL(p, dst[i], arg0[i], arg1[i]);
 	 brw_set_saturate(p, 0);
 	 brw_set_predicate_control_flag_value(p, 0xff);
       }
@@ -657,14 +653,10 @@ void emit_min(struct brw_compile *p,
 
    for (i = 0; i < 4; i++) {
       if (mask & (1<<i)) {	
-	 brw_set_saturate(p, (mask & SATURATE) ? 1 : 0);
-	 brw_MOV(p, dst[i], arg1[i]);
-	 brw_set_saturate(p, 0);
-
 	 brw_CMP(p, brw_null_reg(), BRW_CONDITIONAL_L, arg0[i], arg1[i]);
 
 	 brw_set_saturate(p, (mask & SATURATE) ? 1 : 0);
-	 brw_MOV(p, dst[i], arg0[i]);
+	 brw_SEL(p, dst[i], arg0[i], arg1[i]);
 	 brw_set_saturate(p, 0);
 	 brw_set_predicate_control_flag_value(p, 0xff);
       }