From e1cc8ffd5f2b10e521b6696e1cc39d6e511ff565 Mon Sep 17 00:00:00 2001
From: Christian Gmeiner <cgmeiner@igalia.com>
Date: Fri, 4 Oct 2024 14:35:47 +0200
Subject: [PATCH] etnaviv: isa: Add swizzle instruction

Based on observations of the generated assembly, this instruction appears to:
 - Swizzle the 8/16 component vector in src0 according to the pattern defined in src1.
 - Apply a enable mask from src2 to selectively modify elements.

I encountered this instruction while experimenting with _viv_asm and
packed types.

Here is one exmaple kernel:

kernel void k(global int* out, int a, int b) {
  _viv_char2_packed s;

  _viv_asm(MOV, s.x, s, a);
  _viv_asm(MOV, s.y, s, b);

  out[0] = s.x + s.y;
}

Signed-off-by: Christian Gmeiner <cgmeiner@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33474>
---
 src/etnaviv/isa/etnaviv.xml      | 11 ++++++++++-
 src/etnaviv/isa/tests/disasm.cpp | 17 +++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/src/etnaviv/isa/etnaviv.xml b/src/etnaviv/isa/etnaviv.xml
index 9893aab56e2..a337c1e9d07 100644
--- a/src/etnaviv/isa/etnaviv.xml
+++ b/src/etnaviv/isa/etnaviv.xml
@@ -1275,7 +1275,16 @@ SPDX-License-Identifier: MIT
 	<pattern pos="80">0</pattern> <!-- OPCODE_BIT6 -->
 </bitset>
 
-<!-- swizzle -->
+<bitset name="swizzle" extends="#instruction-alu-src0-src1-src2">
+	<doc>
+		Based on observations of the generated assembly, this instruction appears to:
+		 - Swizzle the 8/16 component vector in src0 according to the pattern defined in src1.
+		 - Apply a enable mask from src2 to selectively modify elements.
+	</doc>
+
+	<pattern low="0" high="5">101011</pattern> <!-- OPC -->
+	<pattern pos="80">0</pattern> <!-- OPCODE_BIT6 -->
+</bitset>
 
 <bitset name="i2i" extends="#instruction-alu-src0-src1">
 	<pattern low="0" high="5">101100</pattern> <!-- OPC -->
diff --git a/src/etnaviv/isa/tests/disasm.cpp b/src/etnaviv/isa/tests/disasm.cpp
index dc0a26a4913..aa027618aa4 100644
--- a/src/etnaviv/isa/tests/disasm.cpp
+++ b/src/etnaviv/isa/tests/disasm.cpp
@@ -155,6 +155,7 @@ INSTANTIATE_TEST_SUITE_P(Opcodes, DisasmTest,
       disasm_state{ {0x00801026, 0x00000004, 0x00000000, 0x00000008}, "ceil              t0.x___, void, void, t0.xxxx\n"},
       disasm_state{ {0x00801027, 0x00000004, 0x00000000, 0x00000008}, "sign              t0.x___, void, void, t0.xxxx\n" },
       disasm_state{ {0x0000002a, 0x00000000, 0x00000000, 0x00000000}, "barrier           void, void, void, void\n" },
+      disasm_state{ {0x0787102b, 0x39202804, 0xc0a802c0, 0x781fdffa}, "swizzle.u8        t7, t2.xyzw, u5.xyyy, 65535\n", FLAG_FAILING_ASM },
       disasm_state{ {0x0080102c, 0x00200804, 0x50001040, 0x00000007}, "i2i.s16           t0.x___, t0.xxxx, 32, void\n" },
       disasm_state{ {0x0381102d, 0x00201804, 0x40000000, 0x00000000}, "i2f.s16           t1.xyz_, t1.xxxx, void, void\n"},
       disasm_state{ {0x0101102e, 0x00201804, 0x80000020, 0x00002000}, "f2i.u32.t0        t1._y__, th1.xxxx, void, void\n"},
@@ -381,3 +382,19 @@ INSTANTIATE_TEST_SUITE_P(ShadowSampler, DisasmTest,
    )
 );
 // clang-format on
+
+// clang-format off
+INSTANTIATE_TEST_SUITE_P(SwizzleVariants, DisasmTest,
+   testing::Values(
+      // seen on GC7000
+      disasm_state{ {0x0782102b, 0x00000804, 0xa000007c ,0x7800001f}, "swizzle.s8        t2, 0, 0, 1\n", FLAG_FAILING_ASM },
+      disasm_state{ {0x0782102b, 0x00002804, 0xa0000040, 0x7800002f}, "swizzle.s8        t2, t2.xxxx, 0, 2\n", FLAG_FAILING_ASM },
+      disasm_state{ {0x0780102b, 0x00002804, 0xa0000040, 0x7800001f}, "swizzle.s8        t0, t2.xxxx, 0, 1\n", FLAG_FAILING_ASM },
+      disasm_state{ {0x0781102b, 0x00002804, 0xa00000c0, 0x7800001f}, "swizzle.s8        t1, t2.xxxx, 1, 1\n", FLAG_FAILING_ASM },
+      disasm_state{ {0x0781102b, 0x00200804, 0x6000007e, 0x7800003f}, "swizzle.s16       t1, 0.000000, 0, 3\n", FLAG_FAILING_ASM },
+      disasm_state{ {0x0781102b, 0x00201804, 0x60000040, 0x780000cf}, "swizzle.s16       t1, t1.xxxx, 0, 12\n", FLAG_FAILING_ASM },
+      disasm_state{ {0x0780102b, 0x00201804, 0x60000040, 0x7800003f}, "swizzle.s16       t0, t1.xxxx, 0, 3\n", FLAG_FAILING_ASM },
+      disasm_state{ {0x0781102b, 0x00202804, 0x600000c0, 0x7800003f}, "swizzle.s16       t1, t2.xxxx, 1, 3\n", FLAG_FAILING_ASM }
+   )
+);
+// clang-format on