From 5df8bf86fe40ae95ad3888cb167ce80c710af227 Mon Sep 17 00:00:00 2001
From: Eric Anholt <eric@anholt.net>
Date: Sun, 29 Mar 2015 21:21:10 -0700
Subject: vc4: Make integer multiply use 24 bits for the low parts.

The hardware uses the low 24 bits in integer multiplies, so we can have
fewer high bits (and so probably drop them more frequently).
---
 src/gallium/drivers/vc4/vc4_program.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

(limited to 'src/gallium/drivers/vc4')

diff --git a/src/gallium/drivers/vc4/vc4_program.c b/src/gallium/drivers/vc4/vc4_program.c
index 56a3a96c1b5..49b94666b88 100644
--- a/src/gallium/drivers/vc4/vc4_program.c
+++ b/src/gallium/drivers/vc4/vc4_program.c
@@ -367,13 +367,13 @@ tgsi_to_qir_umul(struct vc4_compile *c,
                  enum qop op, struct qreg *src, int i)
 {
         struct qreg src0_hi = qir_SHR(c, src[0 * 4 + i],
-                                      qir_uniform_ui(c, 16));
+                                      qir_uniform_ui(c, 24));
         struct qreg src0_lo = qir_AND(c, src[0 * 4 + i],
-                                      qir_uniform_ui(c, 0xffff));
+                                      qir_uniform_ui(c, 0xffffff));
         struct qreg src1_hi = qir_SHR(c, src[1 * 4 + i],
-                                      qir_uniform_ui(c, 16));
+                                      qir_uniform_ui(c, 24));
         struct qreg src1_lo = qir_AND(c, src[1 * 4 + i],
-                                      qir_uniform_ui(c, 0xffff));
+                                      qir_uniform_ui(c, 0xffffff));
 
         struct qreg hilo = qir_MUL24(c, src0_hi, src1_lo);
         struct qreg lohi = qir_MUL24(c, src0_lo, src1_hi);
@@ -381,7 +381,7 @@ tgsi_to_qir_umul(struct vc4_compile *c,
 
         return qir_ADD(c, lolo, qir_SHL(c,
                                         qir_ADD(c, hilo, lohi),
-                                        qir_uniform_ui(c, 16)));
+                                        qir_uniform_ui(c, 24)));
 }
 
 static struct qreg
-- 
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