target/riscv: Add zimop extension

Zimop extension defines an encoding space for 40 MOPs.The Zimop
extension defines 32 MOP instructions named MOP.R.n, where n is
an integer between 0 and 31, inclusive. The Zimop extension
additionally defines 8 MOP instructions named MOP.RR.n, where n
is an integer between 0 and 7.

These 40 MOPs initially are defined to simply write zero to x[rd],
but are designed to be redefined by later extensions to perform some
other action.

Signed-off-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Deepak Gupta <debug@rivosinc.com>
Message-ID: <20240709113652.1239-2-zhiwei_liu@linux.alibaba.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

5 files changed, 52 insertions, 0 deletions

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index c53b0d5..ac50382 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -113,6 +113,7 @@ const RISCVIsaExtData isa_edata_arr[] = {
     ISA_EXT_DATA_ENTRY(zihintntl, PRIV_VERSION_1_10_0, ext_zihintntl),
     ISA_EXT_DATA_ENTRY(zihintpause, PRIV_VERSION_1_10_0, ext_zihintpause),
     ISA_EXT_DATA_ENTRY(zihpm, PRIV_VERSION_1_12_0, ext_zihpm),
+    ISA_EXT_DATA_ENTRY(zimop, PRIV_VERSION_1_13_0, ext_zimop),
     ISA_EXT_DATA_ENTRY(zmmul, PRIV_VERSION_1_12_0, ext_zmmul),
     ISA_EXT_DATA_ENTRY(za64rs, PRIV_VERSION_1_12_0, has_priv_1_11),
     ISA_EXT_DATA_ENTRY(zaamo, PRIV_VERSION_1_12_0, ext_zaamo),
@@ -1471,6 +1472,7 @@ const RISCVCPUMultiExtConfig riscv_cpu_extensions[] = {
     MULTI_EXT_CFG_BOOL("zicsr", ext_zicsr, true),
     MULTI_EXT_CFG_BOOL("zihintntl", ext_zihintntl, true),
     MULTI_EXT_CFG_BOOL("zihintpause", ext_zihintpause, true),
+    MULTI_EXT_CFG_BOOL("zimop", ext_zimop, false),
     MULTI_EXT_CFG_BOOL("zacas", ext_zacas, false),
     MULTI_EXT_CFG_BOOL("zaamo", ext_zaamo, false),
     MULTI_EXT_CFG_BOOL("zalrsc", ext_zalrsc, false),
diff --git a/target/riscv/cpu_cfg.h b/target/riscv/cpu_cfg.h
index fb7eebd..9f53512 100644
--- a/target/riscv/cpu_cfg.h
+++ b/target/riscv/cpu_cfg.h
@@ -71,6 +71,7 @@ struct RISCVCPUConfig {
     bool ext_zihintntl;
     bool ext_zihintpause;
     bool ext_zihpm;
+    bool ext_zimop;
     bool ext_ztso;
     bool ext_smstateen;
     bool ext_sstc;
diff --git a/target/riscv/insn32.decode b/target/riscv/insn32.decode
index f22df04..60da673 100644
--- a/target/riscv/insn32.decode
+++ b/target/riscv/insn32.decode
@@ -38,6 +38,8 @@
 %imm_bs   30:2                   !function=ex_shift_3
 %imm_rnum 20:4
 %imm_z6   26:1 15:5
+%imm_mop5 30:1 26:2 20:2
+%imm_mop3 30:1 26:2
 
 # Argument sets:
 &empty
@@ -56,6 +58,8 @@
 &r2nfvm    vm rd rs1 nf
 &rnfvm     vm rd rs1 rs2 nf
 &k_aes     shamt rs2 rs1 rd
+&mop5 imm rd rs1
+&mop3 imm rd rs1 rs2
 
 # Formats 32:
 @r       .......   ..... ..... ... ..... ....... &r                %rs2 %rs1 %rd
@@ -98,6 +102,9 @@
 @k_aes   .. ..... ..... .....  ... ..... ....... &k_aes  shamt=%imm_bs   %rs2 %rs1 %rd
 @i_aes   .. ..... ..... .....  ... ..... ....... &i      imm=%imm_rnum        %rs1 %rd
 
+@mop5 . . .. .. .... .. ..... ... ..... ....... &mop5 imm=%imm_mop5 %rd %rs1
+@mop3 . . .. .. . ..... ..... ... ..... ....... &mop3 imm=%imm_mop3 %rd %rs1 %rs2
+
 # Formats 64:
 @sh5     .......  ..... .....  ... ..... ....... &shift  shamt=%sh5      %rs1 %rd
 
@@ -1010,3 +1017,7 @@ amocas_w    00101 . . ..... ..... 010 ..... 0101111 @atom_st
 amocas_d    00101 . . ..... ..... 011 ..... 0101111 @atom_st
 # *** RV64 Zacas Standard Extension ***
 amocas_q    00101 . . ..... ..... 100 ..... 0101111 @atom_st
+
+# *** Zimop may-be-operation extension ***
+mop_r_n     1 . 00 .. 0111 .. ..... 100 ..... 1110011 @mop5
+mop_rr_n    1 . 00 .. 1 ..... ..... 100 ..... 1110011 @mop3
diff --git a/target/riscv/insn_trans/trans_rvzimop.c.inc b/target/riscv/insn_trans/trans_rvzimop.c.inc
new file mode 100644
index 0000000..165aacd
--- /dev/null
+++ b/target/riscv/insn_trans/trans_rvzimop.c.inc
@@ -0,0 +1,37 @@
+/*
+ * RISC-V translation routines for May-Be-Operation(zimop).
+ *
+ * Copyright (c) 2024 Alibaba Group.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#define REQUIRE_ZIMOP(ctx) do {           \
+    if (!ctx->cfg_ptr->ext_zimop) {       \
+        return false;                     \
+    }                                     \
+} while (0)
+
+static bool trans_mop_r_n(DisasContext *ctx, arg_mop_r_n *a)
+{
+    REQUIRE_ZIMOP(ctx);
+    gen_set_gpr(ctx, a->rd, ctx->zero);
+    return true;
+}
+
+static bool trans_mop_rr_n(DisasContext *ctx, arg_mop_rr_n *a)
+{
+    REQUIRE_ZIMOP(ctx);
+    gen_set_gpr(ctx, a->rd, ctx->zero);
+    return true;
+}
diff --git a/target/riscv/translate.c b/target/riscv/translate.c
index 0569224..379b682 100644
--- a/target/riscv/translate.c
+++ b/target/riscv/translate.c
@@ -1099,6 +1099,7 @@ static uint32_t opcode_at(DisasContextBase *dcbase, target_ulong pc)
 #include "insn_trans/trans_rvzacas.c.inc"
 #include "insn_trans/trans_rvzawrs.c.inc"
 #include "insn_trans/trans_rvzicbo.c.inc"
+#include "insn_trans/trans_rvzimop.c.inc"
 #include "insn_trans/trans_rvzfa.c.inc"
 #include "insn_trans/trans_rvzfh.c.inc"
 #include "insn_trans/trans_rvk.c.inc"