target/riscv: Add support for Zicond extension

The spec can be found in https://github.com/riscv/riscv-zicond.
Two instructions are added:
 - czero.eqz: Moves zero to a register rd, if the condition rs2 is
   equal to zero, otherwise moves rs1 to rd.
 - czero.nez: Moves zero to a register rd, if the condition rs2 is
   nonzero, otherwise moves rs1 to rd.

Signed-off-by: Weiwei Li <liweiwei@iscas.ac.cn>
Signed-off-by: Junqiang Wang <wangjunqiang@iscas.ac.cn>
Reviewed-by: Frank Chang <frank.chang@sifive.com>
Message-ID: <20230221091009.36545-1-liweiwei@iscas.ac.cn>
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

target/riscv/cpu.c

@@ -74,6 +74,7 @@ struct isa_ext_data {
 static const struct isa_ext_data isa_edata_arr[] = {
     ISA_EXT_DATA_ENTRY(h, false, PRIV_VERSION_1_12_0, ext_h),
     ISA_EXT_DATA_ENTRY(v, false, PRIV_VERSION_1_10_0, ext_v),
+    ISA_EXT_DATA_ENTRY(zicond, true, PRIV_VERSION_1_12_0, ext_zicond),
     ISA_EXT_DATA_ENTRY(zicsr, true, PRIV_VERSION_1_10_0, ext_icsr),
     ISA_EXT_DATA_ENTRY(zifencei, true, PRIV_VERSION_1_10_0, ext_ifencei),
     ISA_EXT_DATA_ENTRY(zihintpause, true, PRIV_VERSION_1_10_0, ext_zihintpause),
@@ -1172,6 +1173,7 @@ static Property riscv_cpu_extensions[] = {
     DEFINE_PROP_BOOL("xventanacondops", RISCVCPU, cfg.ext_XVentanaCondOps, false),
 
     /* These are experimental so mark with 'x-' */
+    DEFINE_PROP_BOOL("x-zicond", RISCVCPU, cfg.ext_zicond, false),
     DEFINE_PROP_BOOL("x-j", RISCVCPU, cfg.ext_j, false),
     /* ePMP 0.9.3 */
     DEFINE_PROP_BOOL("x-epmp", RISCVCPU, cfg.epmp, false),

target/riscv/cpu.h

@@ -434,6 +434,7 @@ struct RISCVCPUConfig {
     bool ext_zkt;
     bool ext_ifencei;
     bool ext_icsr;
+    bool ext_zicond;
     bool ext_zihintpause;
     bool ext_smstateen;
     bool ext_sstc;

target/riscv/insn32.decode

@@ -890,3 +890,7 @@ sm3p1       00 01000 01001 ..... 001 ..... 0010011 @r2
 # *** RV32 Zksed Standard Extension ***
 sm4ed       .. 11000 ..... ..... 000 ..... 0110011 @k_aes
 sm4ks       .. 11010 ..... ..... 000 ..... 0110011 @k_aes
+
+# *** RV32 Zicond Standard Extension ***
+czero_eqz   0000111  ..... ..... 101 ..... 0110011 @r
+czero_nez   0000111  ..... ..... 111 ..... 0110011 @r

target/riscv/insn_trans/trans_rvzicond.c.inc

@@ -0,0 +1,49 @@
+/*
+ * RISC-V translation routines for the Zicond Standard Extension.
+ *
+ * Copyright (c) 2020-2023 PLCT Lab
+ *
+ * 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_ZICOND(ctx) do {          \
+    if (!ctx->cfg_ptr->ext_zicond) {      \
+        return false;                     \
+    }                                     \
+} while (0)
+
+static bool trans_czero_eqz(DisasContext *ctx, arg_czero_eqz *a)
+{
+    REQUIRE_ZICOND(ctx);
+
+    TCGv dest = dest_gpr(ctx, a->rd);
+    TCGv src1 = get_gpr(ctx, a->rs1, EXT_NONE);
+    TCGv src2 = get_gpr(ctx, a->rs2, EXT_NONE);
+
+    tcg_gen_movcond_tl(TCG_COND_EQ, dest, src2, ctx->zero, ctx->zero, src1);
+    gen_set_gpr(ctx, a->rd, dest);
+    return true;
+}
+
+static bool trans_czero_nez(DisasContext *ctx, arg_czero_nez *a)
+{
+    REQUIRE_ZICOND(ctx);
+
+    TCGv dest = dest_gpr(ctx, a->rd);
+    TCGv src1 = get_gpr(ctx, a->rs1, EXT_NONE);
+    TCGv src2 = get_gpr(ctx, a->rs2, EXT_NONE);
+
+    tcg_gen_movcond_tl(TCG_COND_NE, dest, src2, ctx->zero, ctx->zero, src1);
+    gen_set_gpr(ctx, a->rd, dest);
+    return true;
+}

target/riscv/translate.c

@@ -1103,6 +1103,7 @@ static uint32_t opcode_at(DisasContextBase *dcbase, target_ulong pc)
 #include "insn_trans/trans_rvh.c.inc"
 #include "insn_trans/trans_rvv.c.inc"
 #include "insn_trans/trans_rvb.c.inc"
+#include "insn_trans/trans_rvzicond.c.inc"
 #include "insn_trans/trans_rvzawrs.c.inc"
 #include "insn_trans/trans_rvzfh.c.inc"
 #include "insn_trans/trans_rvk.c.inc"