target/mips: introduce decodetree structure for Cavium Octeon extension

This patch adds decodetree for Cavium Octeon extension and
an instruction set extension flag for using it in CPU models.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <165572672162.167724.13656301229517693806.stgit@pasha-ThinkPad-X280>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

target/mips/mips-defs.h

@@ -42,6 +42,7 @@
 #define INSN_LOONGSON2E   0x0000040000000000ULL
 #define INSN_LOONGSON2F   0x0000080000000000ULL
 #define INSN_LOONGSON3A   0x0000100000000000ULL
+#define INSN_OCTEON       0x0000200000000000ULL
 /*
  *   bits 52-63: vendor-specific ASEs
  */

target/mips/tcg/meson.build

@@ -3,6 +3,7 @@ gen = [
   decodetree.process('msa.decode', extra_args: '--decode=decode_ase_msa'),
   decodetree.process('tx79.decode', extra_args: '--static-decode=decode_tx79'),
   decodetree.process('vr54xx.decode', extra_args: '--decode=decode_ext_vr54xx'),
+  decodetree.process('octeon.decode', extra_args: '--decode=decode_ext_octeon'),
 ]
 
 mips_ss.add(gen)
@@ -24,6 +25,7 @@ mips_ss.add(files(
 ))
 mips_ss.add(when: 'TARGET_MIPS64', if_true: files(
   'tx79_translate.c',
+  'octeon_translate.c',
 ), if_false: files(
   'mxu_translate.c',
 ))

target/mips/tcg/octeon.decode

@@ -0,0 +1,6 @@
+# Octeon Architecture Module instruction set
+#
+# Copyright (C) 2022 Pavel Dovgalyuk
+#
+# SPDX-License-Identifier: LGPL-2.1-or-later
+#

target/mips/tcg/octeon_translate.c

@@ -0,0 +1,16 @@
+/*
+ * Octeon-specific instructions translation routines
+ *
+ *  Copyright (c) 2022 Pavel Dovgalyuk
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "tcg/tcg-op.h"
+#include "tcg/tcg-op-gvec.h"
+#include "exec/helper-gen.h"
+#include "translate.h"
+
+/* Include the auto-generated decoder.  */
+#include "decode-octeon.c.inc"

target/mips/tcg/translate.c

@@ -15955,6 +15955,11 @@ static void decode_opc(CPUMIPSState *env, DisasContext *ctx)
     if (cpu_supports_isa(env, INSN_VR54XX) && decode_ext_vr54xx(ctx, ctx->opcode)) {
         return;
     }
+#if defined(TARGET_MIPS64)
+    if (cpu_supports_isa(env, INSN_OCTEON) && decode_ext_octeon(ctx, ctx->opcode)) {
+        return;
+    }
+#endif
 
     /* ISA extensions */
     if (ase_msa_available(env) && decode_ase_msa(ctx, ctx->opcode)) {

target/mips/tcg/translate.h

@@ -215,6 +215,7 @@ bool decode_ase_msa(DisasContext *ctx, uint32_t insn);
 bool decode_ext_txx9(DisasContext *ctx, uint32_t insn);
 #if defined(TARGET_MIPS64)
 bool decode_ext_tx79(DisasContext *ctx, uint32_t insn);
+bool decode_ext_octeon(DisasContext *ctx, uint32_t insn);
 #endif
 bool decode_ext_vr54xx(DisasContext *ctx, uint32_t insn);