[Mesa-dev] [PATCH 1/2] i965/emit: Add assertions for accumulator restrictions

[Jason Ekstrand]

---
 src/mesa/drivers/dri/i965/brw_eu_emit.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_eu_emit.c 
b/src/mesa/drivers/dri/i965/brw_eu_emit.c
index 637fd07..b2f7409 100644
--- a/src/mesa/drivers/dri/i965/brw_eu_emit.c
+++ b/src/mesa/drivers/dri/i965/brw_eu_emit.c
@@ -235,6 +235,15 @@ validate_reg(const struct brw_device_info *devinfo,
        reg.file == BRW_ARF_NULL)
       return;
 
+   /* From the IBV PRM Vol. 4, Pt. 3, Section 3.3.3.5:
+    *
+    * Swizzling is not allowed when an accumulator is used as an implicit
+    * source or an explicit source in an instruction.
+    */
+   if (reg.file == BRW_ARCHITECTURE_REGISTER_FILE &&
+       reg.nr == BRW_ARF_ACCUMULATOR)
+      assert(reg.dw1.bits.swizzle == BRW_SWIZZLE_XYZW);
+
    assert(reg.hstride >= 0 && reg.hstride < ARRAY_SIZE(hstride_for_reg));
    hstride = hstride_for_reg[reg.hstride];
 
@@ -443,6 +452,13 @@ brw_set_src1(struct brw_codegen *p, brw_inst *inst, struct 
brw_reg reg)
    if (reg.file != BRW_ARCHITECTURE_REGISTER_FILE)
       assert(reg.nr < 128);
 
+   /* From the IBV PRM Vol. 4, Pt. 3, Section 3.3.3.5:
+    *
+    * Accumulator registers may be accessed explicitly as src0 operands only.
+    */
+   assert(reg.file != BRW_ARCHITECTURE_REGISTER_FILE ||
+          reg.nr != BRW_ARF_ACCUMULATOR);
+
    gen7_convert_mrf_to_grf(p, &reg);
    assert(reg.file != BRW_MESSAGE_REGISTER_FILE);
 
-- 
2.5.0.400.gff86faf

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