target/riscv: zfh: half-precision load and store

Signed-off-by: Kito Cheng <kito.cheng@sifive.com>
Signed-off-by: Chih-Min Chao <chihmin.chao@sifive.com>
Signed-off-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20211210074329.5775-2-frank.chang@sifive.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu.h

@@ -312,6 +312,7 @@ struct RISCVCPU {
         bool ext_counters;
         bool ext_ifencei;
         bool ext_icsr;
+        bool ext_zfh;
 
         char *priv_spec;
         char *user_spec;

target/riscv/insn32.decode

@@ -726,3 +726,7 @@ binv       0110100 .......... 001 ..... 0110011 @r
 binvi      01101. ........... 001 ..... 0010011 @sh
 bset       0010100 .......... 001 ..... 0110011 @r
 bseti      00101. ........... 001 ..... 0010011 @sh
+
+# *** RV32 Zfh Extension ***
+flh        ............   ..... 001 ..... 0000111 @i
+fsh        .......  ..... ..... 001 ..... 0100111 @s

target/riscv/insn_trans/trans_rvzfh.c.inc

@@ -0,0 +1,65 @@
+/*
+ * RISC-V translation routines for the RV64Zfh Standard Extension.
+ *
+ * Copyright (c) 2020 Chih-Min Chao, chihmin.chao@sifive.com
+ *
+ * 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_ZFH(ctx) do { \
+    if (!ctx->ext_zfh) {      \
+        return false;         \
+    }                         \
+} while (0)
+
+static bool trans_flh(DisasContext *ctx, arg_flh *a)
+{
+    TCGv_i64 dest;
+    TCGv t0;
+
+    REQUIRE_FPU;
+    REQUIRE_ZFH(ctx);
+
+    t0 = get_gpr(ctx, a->rs1, EXT_NONE);
+    if (a->imm) {
+        TCGv temp = temp_new(ctx);
+        tcg_gen_addi_tl(temp, t0, a->imm);
+        t0 = temp;
+    }
+
+    dest = cpu_fpr[a->rd];
+    tcg_gen_qemu_ld_i64(dest, t0, ctx->mem_idx, MO_TEUW);
+    gen_nanbox_h(dest, dest);
+
+    mark_fs_dirty(ctx);
+    return true;
+}
+
+static bool trans_fsh(DisasContext *ctx, arg_fsh *a)
+{
+    TCGv t0;
+
+    REQUIRE_FPU;
+    REQUIRE_ZFH(ctx);
+
+    t0 = get_gpr(ctx, a->rs1, EXT_NONE);
+    if (a->imm) {
+        TCGv temp = tcg_temp_new();
+        tcg_gen_addi_tl(temp, t0, a->imm);
+        t0 = temp;
+    }
+
+    tcg_gen_qemu_st_i64(cpu_fpr[a->rs2], t0, ctx->mem_idx, MO_TEUW);
+
+    return true;
+}

target/riscv/translate.c

@@ -73,6 +73,7 @@ typedef struct DisasContext {
     RISCVMXL ol;
     bool virt_enabled;
     bool ext_ifencei;
+    bool ext_zfh;
     bool hlsx;
     /* vector extension */
     bool vill;
@@ -134,6 +135,11 @@ static void gen_nanbox_s(TCGv_i64 out, TCGv_i64 in)
     tcg_gen_ori_i64(out, in, MAKE_64BIT_MASK(32, 32));
 }
 
+static void gen_nanbox_h(TCGv_i64 out, TCGv_i64 in)
+{
+    tcg_gen_ori_i64(out, in, MAKE_64BIT_MASK(16, 48));
+}
+
 /*
  * A narrow n-bit operation, where n < FLEN, checks that input operands
  * are correctly Nan-boxed, i.e., all upper FLEN - n bits are 1.
@@ -574,6 +580,7 @@ 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_rvzfh.c.inc"
 #include "insn_trans/trans_privileged.c.inc"
 
 /* Include the auto-generated decoder for 16 bit insn */
@@ -626,6 +633,7 @@ static void riscv_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs)
     ctx->misa_ext = env->misa_ext;
     ctx->frm = -1;  /* unknown rounding mode */
     ctx->ext_ifencei = cpu->cfg.ext_ifencei;
+    ctx->ext_zfh = cpu->cfg.ext_zfh;
     ctx->vlen = cpu->cfg.vlen;
     ctx->mstatus_hs_fs = FIELD_EX32(tb_flags, TB_FLAGS, MSTATUS_HS_FS);
     ctx->hlsx = FIELD_EX32(tb_flags, TB_FLAGS, HLSX);