target/riscv: zfh: implement zfhmin extension

Zfhmin extension is a subset of Zfh extension, consisting only of data
transfer and conversion instructions.

If enabled, only the following instructions from Zfh extension are
included:
  * flh, fsh, fmv.x.h, fmv.h.x, fcvt.s.h, fcvt.h.s
  * If D extension is present: fcvt.d.h, fcvt.h.d

Signed-off-by: Frank Chang <frank.chang@sifive.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20211210074329.5775-8-frank.chang@sifive.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu.h

@@ -313,6 +313,7 @@ struct RISCVCPU {
         bool ext_ifencei;
         bool ext_icsr;
         bool ext_zfh;
+        bool ext_zfhmin;
 
         char *priv_spec;
         char *user_spec;

target/riscv/insn_trans/trans_rvzfh.c.inc

@@ -22,13 +22,19 @@
     }                         \
 } while (0)
 
+#define REQUIRE_ZFH_OR_ZFHMIN(ctx) do {       \
+    if (!(ctx->ext_zfh || ctx->ext_zfhmin)) { \
+        return false;                         \
+    }                                         \
+} while (0)
+
 static bool trans_flh(DisasContext *ctx, arg_flh *a)
 {
     TCGv_i64 dest;
     TCGv t0;
 
     REQUIRE_FPU;
-    REQUIRE_ZFH(ctx);
+    REQUIRE_ZFH_OR_ZFHMIN(ctx);
 
     t0 = get_gpr(ctx, a->rs1, EXT_NONE);
     if (a->imm) {
@@ -50,7 +56,7 @@ static bool trans_fsh(DisasContext *ctx, arg_fsh *a)
     TCGv t0;
 
     REQUIRE_FPU;
-    REQUIRE_ZFH(ctx);
+    REQUIRE_ZFH_OR_ZFHMIN(ctx);
 
     t0 = get_gpr(ctx, a->rs1, EXT_NONE);
     if (a->imm) {
@@ -283,7 +289,7 @@ static bool trans_fmax_h(DisasContext *ctx, arg_fmax_h *a)
 static bool trans_fcvt_s_h(DisasContext *ctx, arg_fcvt_s_h *a)
 {
     REQUIRE_FPU;
-    REQUIRE_ZFH(ctx);
+    REQUIRE_ZFH_OR_ZFHMIN(ctx);
 
     gen_set_rm(ctx, a->rm);
     gen_helper_fcvt_s_h(cpu_fpr[a->rd], cpu_env, cpu_fpr[a->rs1]);
@@ -296,7 +302,7 @@ static bool trans_fcvt_s_h(DisasContext *ctx, arg_fcvt_s_h *a)
 static bool trans_fcvt_d_h(DisasContext *ctx, arg_fcvt_d_h *a)
 {
     REQUIRE_FPU;
-    REQUIRE_ZFH(ctx);
+    REQUIRE_ZFH_OR_ZFHMIN(ctx);
     REQUIRE_EXT(ctx, RVD);
 
     gen_set_rm(ctx, a->rm);
@@ -311,7 +317,7 @@ static bool trans_fcvt_d_h(DisasContext *ctx, arg_fcvt_d_h *a)
 static bool trans_fcvt_h_s(DisasContext *ctx, arg_fcvt_h_s *a)
 {
     REQUIRE_FPU;
-    REQUIRE_ZFH(ctx);
+    REQUIRE_ZFH_OR_ZFHMIN(ctx);
 
     gen_set_rm(ctx, a->rm);
     gen_helper_fcvt_h_s(cpu_fpr[a->rd], cpu_env, cpu_fpr[a->rs1]);
@@ -324,7 +330,7 @@ static bool trans_fcvt_h_s(DisasContext *ctx, arg_fcvt_h_s *a)
 static bool trans_fcvt_h_d(DisasContext *ctx, arg_fcvt_h_d *a)
 {
     REQUIRE_FPU;
-    REQUIRE_ZFH(ctx);
+    REQUIRE_ZFH_OR_ZFHMIN(ctx);
     REQUIRE_EXT(ctx, RVD);
 
     gen_set_rm(ctx, a->rm);
@@ -441,7 +447,7 @@ static bool trans_fcvt_h_wu(DisasContext *ctx, arg_fcvt_h_wu *a)
 static bool trans_fmv_x_h(DisasContext *ctx, arg_fmv_x_h *a)
 {
     REQUIRE_FPU;
-    REQUIRE_ZFH(ctx);
+    REQUIRE_ZFH_OR_ZFHMIN(ctx);
 
     TCGv dest = dest_gpr(ctx, a->rd);
 
@@ -461,7 +467,7 @@ static bool trans_fmv_x_h(DisasContext *ctx, arg_fmv_x_h *a)
 static bool trans_fmv_h_x(DisasContext *ctx, arg_fmv_h_x *a)
 {
     REQUIRE_FPU;
-    REQUIRE_ZFH(ctx);
+    REQUIRE_ZFH_OR_ZFHMIN(ctx);
 
     TCGv t0 = get_gpr(ctx, a->rs1, EXT_ZERO);
 

target/riscv/translate.c

@@ -74,6 +74,7 @@ typedef struct DisasContext {
     bool virt_enabled;
     bool ext_ifencei;
     bool ext_zfh;
+    bool ext_zfhmin;
     bool hlsx;
     /* vector extension */
     bool vill;
@@ -644,6 +645,7 @@ static void riscv_tr_init_disas_context(DisasContextBase *dcbase, CPUState *cs)
     ctx->frm = -1;  /* unknown rounding mode */
     ctx->ext_ifencei = cpu->cfg.ext_ifencei;
     ctx->ext_zfh = cpu->cfg.ext_zfh;
+    ctx->ext_zfhmin = cpu->cfg.ext_zfhmin;
     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);