RISC-V: Adding XTheadCondMov ISA extension

This patch adds support for the XTheadCondMov ISA extension.
The patch uses the T-Head specific decoder and translation.

Co-developed-by: LIU Zhiwei <zhiwei_liu@linux.alibaba.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>
Message-Id: <20230131202013.2541053-7-christoph.muellner@vrull.eu>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu.c

@@ -113,6 +113,7 @@ static const struct isa_ext_data isa_edata_arr[] = {
     ISA_EXT_DATA_ENTRY(xtheadbb, true, PRIV_VERSION_1_11_0, ext_xtheadbb),
     ISA_EXT_DATA_ENTRY(xtheadbs, true, PRIV_VERSION_1_11_0, ext_xtheadbs),
     ISA_EXT_DATA_ENTRY(xtheadcmo, true, PRIV_VERSION_1_11_0, ext_xtheadcmo),
+    ISA_EXT_DATA_ENTRY(xtheadcondmov, true, PRIV_VERSION_1_11_0, ext_xtheadcondmov),
     ISA_EXT_DATA_ENTRY(xtheadsync, true, PRIV_VERSION_1_11_0, ext_xtheadsync),
     ISA_EXT_DATA_ENTRY(xventanacondops, true, PRIV_VERSION_1_12_0, ext_XVentanaCondOps),
 };
@@ -1097,6 +1098,7 @@ static Property riscv_cpu_extensions[] = {
     DEFINE_PROP_BOOL("xtheadbb", RISCVCPU, cfg.ext_xtheadbb, false),
     DEFINE_PROP_BOOL("xtheadbs", RISCVCPU, cfg.ext_xtheadbs, false),
     DEFINE_PROP_BOOL("xtheadcmo", RISCVCPU, cfg.ext_xtheadcmo, false),
+    DEFINE_PROP_BOOL("xtheadcondmov", RISCVCPU, cfg.ext_xtheadcondmov, false),
     DEFINE_PROP_BOOL("xtheadsync", RISCVCPU, cfg.ext_xtheadsync, false),
     DEFINE_PROP_BOOL("xventanacondops", RISCVCPU, cfg.ext_XVentanaCondOps, false),
 

target/riscv/cpu.h

@@ -477,6 +477,7 @@ struct RISCVCPUConfig {
     bool ext_xtheadbb;
     bool ext_xtheadbs;
     bool ext_xtheadcmo;
+    bool ext_xtheadcondmov;
     bool ext_xtheadsync;
     bool ext_XVentanaCondOps;
 

target/riscv/insn_trans/trans_xthead.c.inc

@@ -40,6 +40,12 @@
     }                                            \
 } while (0)
 
+#define REQUIRE_XTHEADCONDMOV(ctx) do {          \
+    if (!ctx->cfg_ptr->ext_xtheadcondmov) {      \
+        return false;                            \
+    }                                            \
+} while (0)
+
 #define REQUIRE_XTHEADSYNC(ctx) do {             \
     if (!ctx->cfg_ptr->ext_xtheadsync) {         \
         return false;                            \
@@ -264,6 +270,35 @@ NOP_PRIVCHECK(th_l2cache_call, REQUIRE_XTHEADCMO, REQUIRE_PRIV_MS)
 NOP_PRIVCHECK(th_l2cache_ciall, REQUIRE_XTHEADCMO, REQUIRE_PRIV_MS)
 NOP_PRIVCHECK(th_l2cache_iall, REQUIRE_XTHEADCMO, REQUIRE_PRIV_MS)
 
+/* XTheadCondMov */
+
+static bool gen_th_condmove(DisasContext *ctx, arg_r *a, TCGCond cond)
+{
+    TCGv src1 = get_gpr(ctx, a->rs1, EXT_NONE);
+    TCGv src2 = get_gpr(ctx, a->rs2, EXT_NONE);
+    TCGv old = get_gpr(ctx, a->rd, EXT_NONE);
+    TCGv dest = dest_gpr(ctx, a->rd);
+
+    tcg_gen_movcond_tl(cond, dest, src2, ctx->zero, src1, old);
+
+    gen_set_gpr(ctx, a->rd, dest);
+    return true;
+}
+
+/* th.mveqz: "if (rs2 == 0) rd = rs1;" */
+static bool trans_th_mveqz(DisasContext *ctx, arg_th_mveqz *a)
+{
+    REQUIRE_XTHEADCONDMOV(ctx);
+    return gen_th_condmove(ctx, a, TCG_COND_EQ);
+}
+
+/* th.mvnez: "if (rs2 != 0) rd = rs1;" */
+static bool trans_th_mvnez(DisasContext *ctx, arg_th_mveqz *a)
+{
+    REQUIRE_XTHEADCONDMOV(ctx);
+    return gen_th_condmove(ctx, a, TCG_COND_NE);
+}
+
 /* XTheadSync */
 
 static bool trans_th_sfence_vmas(DisasContext *ctx, arg_th_sfence_vmas *a)

target/riscv/translate.c

@@ -134,7 +134,7 @@ static bool has_xthead_p(DisasContext *ctx  __attribute__((__unused__)))
 {
     return ctx->cfg_ptr->ext_xtheadba || ctx->cfg_ptr->ext_xtheadbb ||
            ctx->cfg_ptr->ext_xtheadbs || ctx->cfg_ptr->ext_xtheadcmo ||
-           ctx->cfg_ptr->ext_xtheadsync;
+           ctx->cfg_ptr->ext_xtheadcondmov || ctx->cfg_ptr->ext_xtheadsync;
 }
 
 #define MATERIALISE_EXT_PREDICATE(ext)  \

target/riscv/xthead.decode

@@ -84,6 +84,10 @@ th_l2cache_call  0000000 10101 00000 000 00000 0001011
 th_l2cache_ciall 0000000 10111 00000 000 00000 0001011
 th_l2cache_iall  0000000 10110 00000 000 00000 0001011
 
+# XTheadCondMov
+th_mveqz         0100000 ..... .....  001 ..... 0001011 @r
+th_mvnez         0100001 ..... .....  001 ..... 0001011 @r
+
 # XTheadSync
 th_sfence_vmas   0000010 ..... ..... 000 00000 0001011 @rs2_s
 th_sync          0000000 11000 00000 000 00000 0001011