Mesa (master): vc4: Abstract out the field-merging logic for instructions.

[Eric Anholt]

Module: Mesa
Branch: master
Commit: 48af7426f295a02ea68c4b460e006c289b10192c
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=48af7426f295a02ea68c4b460e006c289b10192c

Author: Eric Anholt <eric at anholt.net>
Date:   Thu Oct  2 23:22:03 2014 -0700

vc4: Abstract out the field-merging logic for instructions.

I'm going to be doing the same logic for some more fields next.

---

 src/gallium/drivers/vc4/vc4_qpu.c |   28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/src/gallium/drivers/vc4/vc4_qpu.c b/src/gallium/drivers/vc4/vc4_qpu.c
index bf385e3..27fc309 100644
--- a/src/gallium/drivers/vc4/vc4_qpu.c
+++ b/src/gallium/drivers/vc4/vc4_qpu.c
@@ -185,23 +185,29 @@ qpu_m_alu2(enum qpu_op_mul op,
         return inst;
 }
 
+static uint64_t
+merge_fields(uint64_t merge,
+             uint64_t add, uint64_t mul,
+             uint64_t mask, uint64_t ignore)
+{
+        if ((add & mask) == ignore)
+                return (merge & ~mask) | (mul & mask);
+        else if ((mul & mask) == ignore)
+                return (merge & ~mask) | (add & mask);
+        else {
+                assert((add & mask) == (mul & mask));
+                return merge;
+        }
+}
+
 uint64_t
 qpu_inst(uint64_t add, uint64_t mul)
 {
         uint64_t merge = ((add & ~QPU_WADDR_MUL_MASK) |
                           (mul & ~QPU_WADDR_ADD_MASK));
 
-        /* If either one has no signal field, then use the other's signal field.
-         * (since QPU_SIG_NONE != 0).
-         */
-        if (QPU_GET_FIELD(add, QPU_SIG) == QPU_SIG_NONE)
-                merge = (merge & ~QPU_SIG_MASK) | (mul & QPU_SIG_MASK);
-        else if (QPU_GET_FIELD(mul, QPU_SIG) == QPU_SIG_NONE)
-                merge = (merge & ~QPU_SIG_MASK) | (add & QPU_SIG_MASK);
-        else {
-                assert(QPU_GET_FIELD(add, QPU_SIG) ==
-                       QPU_GET_FIELD(mul, QPU_SIG));
-        }
+        merge = merge_fields(merge, add, mul, QPU_SIG_MASK,
+                             QPU_SET_FIELD(QPU_SIG_NONE, QPU_SIG));
 
         return merge;
 }