[PATCH v5 3/3] disas: diassemble RISC-V xlrbr (crc32) instructions

[James Wainwright <james.wainwright@lowrisc.org>]

From: Emmanuel Blot <eblot@rivosinc.com>

Placed in a separate file as a vendor extension.

Signed-off-by: James Wainwright <james.wainwright@lowrisc.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
---
 MAINTAINERS         |  2 +-
 disas/meson.build   |  3 +-
 disas/riscv-xlrbr.c | 79 +++++++++++++++++++++++++++++++++++++++++++++
 disas/riscv-xlrbr.h | 19 +++++++++++
 disas/riscv.c       |  2 ++
 5 files changed, 103 insertions(+), 2 deletions(-)
 create mode 100644 disas/riscv-xlrbr.c
 create mode 100644 disas/riscv-xlrbr.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 847fd414bc..12f106f4c4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4154,7 +4154,7 @@ M: Alistair Francis <Alistair.Francis@wdc.com>
 L: qemu-riscv@nongnu.org
 S: Maintained
 F: tcg/riscv64/
-F: disas/riscv.[ch]
+F: disas/riscv*.[ch]
 
 S390 TCG target
 M: Richard Henderson <richard.henderson@linaro.org>
diff --git a/disas/meson.build b/disas/meson.build
index bbfa119783..42977a1f74 100644
--- a/disas/meson.build
+++ b/disas/meson.build
@@ -7,7 +7,8 @@ common_ss.add(when: 'CONFIG_MIPS_DIS', if_true: files('mips.c', 'nanomips.c'))
 common_ss.add(when: 'CONFIG_RISCV_DIS', if_true: files(
     'riscv.c',
     'riscv-xthead.c',
-    'riscv-xventana.c'
+    'riscv-xventana.c',
+    'riscv-xlrbr.c'
 ))
 common_ss.add(when: 'CONFIG_SH4_DIS', if_true: files('sh4.c'))
 common_ss.add(when: 'CONFIG_SPARC_DIS', if_true: files('sparc.c'))
diff --git a/disas/riscv-xlrbr.c b/disas/riscv-xlrbr.c
new file mode 100644
index 0000000000..57cb434523
--- /dev/null
+++ b/disas/riscv-xlrbr.c
@@ -0,0 +1,79 @@
+/*
+ * QEMU RISC-V Disassembler for xlrbr matching the unratified Zbr CRC32
+ * bitmanip extension v0.93.
+ *
+ * Copyright (c) 2023 Rivos Inc
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+
+#include "disas/riscv.h"
+#include "disas/riscv-xlrbr.h"
+
+typedef enum {
+    /* 0 is reserved for rv_op_illegal. */
+    rv_op_crc32_b = 1,
+    rv_op_crc32_h = 2,
+    rv_op_crc32_w = 3,
+    rv_op_crc32_d = 4,
+    rv_op_crc32c_b = 5,
+    rv_op_crc32c_h = 6,
+    rv_op_crc32c_w = 7,
+    rv_op_crc32c_d = 8,
+} rv_xlrbr_op;
+
+const rv_opcode_data rv_xlrbr_opcode_data[] = {
+    { "illegal", rv_codec_illegal, rv_fmt_none, NULL, 0, 0, 0 },
+    { "crc32.b", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
+    { "crc32.h", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
+    { "crc32.w", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
+    { "crc32.d", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
+    { "crc32c.b", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
+    { "crc32c.h", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
+    { "crc32c.w", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
+    { "crc32c.d", rv_codec_r, rv_fmt_rd_rs1, NULL, 0, 0, 0 },
+};
+
+void decode_xlrbr(rv_decode *dec, rv_isa isa)
+{
+    rv_inst inst = dec->inst;
+    rv_opcode op = rv_op_illegal;
+
+    switch ((inst >> 0) & 0b1111111) {
+    case 0b0010011:
+        switch ((inst >> 12) & 0b111) {
+        case 0b001:
+            switch ((inst >> 20 & 0b111111111111)) {
+            case 0b011000010000:
+                op = rv_op_crc32_b;
+                break;
+            case 0b011000010001:
+                op = rv_op_crc32_h;
+                break;
+            case 0b011000010010:
+                op = rv_op_crc32_w;
+                break;
+            case 0b011000010011:
+                op = rv_op_crc32_d;
+                break;
+            case 0b011000011000:
+                op = rv_op_crc32c_b;
+                break;
+            case 0b011000011001:
+                op = rv_op_crc32c_h;
+                break;
+            case 0b011000011010:
+                op = rv_op_crc32c_w;
+                break;
+            case 0b011000011011:
+                op = rv_op_crc32c_d;
+                break;
+            }
+            break;
+        }
+        break;
+    }
+    dec->op = op;
+}
diff --git a/disas/riscv-xlrbr.h b/disas/riscv-xlrbr.h
new file mode 100644
index 0000000000..939a69ea6d
--- /dev/null
+++ b/disas/riscv-xlrbr.h
@@ -0,0 +1,19 @@
+/*
+ * QEMU RISC-V Disassembler for xlrbr matching the unratified Zbr CRC32
+ * bitmanip extension v0.93.
+ *
+ * Copyright (c) 2023 Rivos Inc
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef DISAS_RISCV_XLRBR_H
+#define DISAS_RISCV_XLRBR_H
+
+#include "disas/riscv.h"
+
+extern const rv_opcode_data rv_xlrbr_opcode_data[];
+
+void decode_xlrbr(rv_decode *, rv_isa);
+
+#endif /* DISAS_RISCV_XLRBR_H */
diff --git a/disas/riscv.c b/disas/riscv.c
index 6f2667482d..d416a4d6b3 100644
--- a/disas/riscv.c
+++ b/disas/riscv.c
@@ -26,6 +26,7 @@
 /* Vendor extensions */
 #include "disas/riscv-xthead.h"
 #include "disas/riscv-xventana.h"
+#include "disas/riscv-xlrbr.h"
 
 typedef enum {
     /* 0 is reserved for rv_op_illegal. */
@@ -5434,6 +5435,7 @@ static GString *disasm_inst(rv_isa isa, uint64_t pc, rv_inst inst,
         { has_xtheadmempair_p, xthead_opcode_data, decode_xtheadmempair },
         { has_xtheadsync_p, xthead_opcode_data, decode_xtheadsync },
         { has_XVentanaCondOps_p, ventana_opcode_data, decode_xventanacondops },
+        { has_xlrbr_p, rv_xlrbr_opcode_data, decode_xlrbr },
     };
 
     for (size_t i = 0; i < ARRAY_SIZE(decoders); i++) {
-- 
2.48.1