target/mips: Convert MSA ELM instruction format to decodetree

Convert instructions with an immediate element index
and data format df/n to decodetree.

Since the 'data format' and 'n' fields are constant values,
use tcg_constant_i32() instead of a TCG temporaries.

Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20211028210843.2120802-25-f4bug@amsat.org>

target/mips/tcg/msa.decode

@@ -18,7 +18,10 @@
 &msa_ldi            df  wd       sa
 &msa_i              df  wd ws    sa
 &msa_bit            df  wd ws       m
+&msa_elm_df         df  wd ws       n
 
+%elm_df             16:6 !function=elm_df
+%elm_n              16:6 !function=elm_n
 %bit_df             16:7 !function=bit_df
 %bit_m              16:7 !function=bit_m
 %2r_df_w            16:1 !function=plus_2
@@ -29,6 +32,7 @@
 @ldst               ...... sa:s10 ws:5 wd:5 .... df:2       &msa_i
 @bz_v               ...... ... ..    wt:5 sa:16             &msa_bz df=3
 @bz                 ...... ...  df:2 wt:5 sa:16             &msa_bz
+@elm_df             ...... .... ......    ws:5 wd:5 ......  &msa_elm_df df=%elm_df n=%elm_n
 @vec                ...... .....     wt:5 ws:5 wd:5 ......  &msa_r df=0
 @2r                 ...... ........  df:2 ws:5 wd:5 ......  &msa_r wt=0
 @2rf                ...... ......... .    ws:5 wd:5 ......  &msa_r wt=0 df=%2r_df_w
@@ -161,6 +165,10 @@ BNZ                 010001 111 .. ..... ................    @bz
   HSUB_S            011110 110.. ..... ..... .....  010101  @3r
   HSUB_U            011110 111.. ..... ..... .....  010101  @3r
 
+  SLDI              011110 0000 ...... ..... .....  011001  @elm_df
+  SPLATI            011110 0001 ...... ..... .....  011001  @elm_df
+  INSVE             011110 0101 ...... ..... .....  011001  @elm_df
+
   FCAF              011110 0000 . ..... ..... ..... 011010  @3rf_w
   FCUN              011110 0001 . ..... ..... ..... 011010  @3rf_w
   FCEQ              011110 0010 . ..... ..... ..... 011010  @3rf_w

target/mips/tcg/msa_translate.c

@@ -17,6 +17,8 @@
 #include "fpu_helper.h"
 #include "internal.h"
 
+static int elm_n(DisasContext *ctx, int x);
+static int elm_df(DisasContext *ctx, int x);
 static int bit_m(DisasContext *ctx, int x);
 static int bit_df(DisasContext *ctx, int x);
 
@@ -42,15 +44,12 @@ enum {
 
 enum {
     /* ELM instructions df(bits 21..16) = _b, _h, _w, _d */
-    OPC_SLDI_df     = (0x0 << 22) | (0x00 << 16) | OPC_MSA_ELM,
     OPC_CTCMSA      = (0x0 << 22) | (0x3E << 16) | OPC_MSA_ELM,
-    OPC_SPLATI_df   = (0x1 << 22) | (0x00 << 16) | OPC_MSA_ELM,
     OPC_CFCMSA      = (0x1 << 22) | (0x3E << 16) | OPC_MSA_ELM,
     OPC_COPY_S_df   = (0x2 << 22) | (0x00 << 16) | OPC_MSA_ELM,
     OPC_MOVE_V      = (0x2 << 22) | (0x3E << 16) | OPC_MSA_ELM,
     OPC_COPY_U_df   = (0x3 << 22) | (0x00 << 16) | OPC_MSA_ELM,
     OPC_INSERT_df   = (0x4 << 22) | (0x00 << 16) | OPC_MSA_ELM,
-    OPC_INSVE_df    = (0x5 << 22) | (0x00 << 16) | OPC_MSA_ELM,
 };
 
 static const char msaregnames[][6] = {
@@ -107,6 +106,24 @@ static int df_extract_df(DisasContext *ctx, int x, const struct dfe *s)
     return -1;
 }
 
+static const struct dfe df_elm[] = {
+    /* Table 3.26 ELM Instruction Format */
+    [DF_BYTE]   = {4, 2, 0b00},
+    [DF_HALF]   = {3, 3, 0b100},
+    [DF_WORD]   = {2, 4, 0b1100},
+    [DF_DOUBLE] = {1, 5, 0b11100}
+};
+
+static int elm_n(DisasContext *ctx, int x)
+{
+    return df_extract_val(ctx, x, df_elm);
+}
+
+static int elm_df(DisasContext *ctx, int x)
+{
+    return df_extract_df(ctx, x, df_elm);
+}
+
 static const struct dfe df_bit[] = {
     /* Table 3.28 BIT Instruction Format */
     [DF_BYTE]   = {3, 4, 0b1110},
@@ -551,6 +568,30 @@ static void gen_msa_elm_3e(DisasContext *ctx)
     tcg_temp_free_i32(tsr);
 }
 
+static bool trans_msa_elm(DisasContext *ctx, arg_msa_elm_df *a,
+                          gen_helper_piiii *gen_msa_elm_df)
+{
+    if (a->df < 0) {
+        return false;
+    }
+
+    if (!check_msa_enabled(ctx)) {
+        return true;
+    }
+
+    gen_msa_elm_df(cpu_env,
+                   tcg_constant_i32(a->df),
+                   tcg_constant_i32(a->wd),
+                   tcg_constant_i32(a->ws),
+                   tcg_constant_i32(a->n));
+
+    return true;
+}
+
+TRANS(SLDI,   trans_msa_elm, gen_helper_msa_sldi_df);
+TRANS(SPLATI, trans_msa_elm, gen_helper_msa_splati_df);
+TRANS(INSVE,  trans_msa_elm, gen_helper_msa_insve_df);
+
 static void gen_msa_elm_df(DisasContext *ctx, uint32_t df, uint32_t n)
 {
 #define MASK_MSA_ELM(op)    (MASK_MSA_MINOR(op) | (op & (0xf << 22)))
@@ -560,18 +601,8 @@ static void gen_msa_elm_df(DisasContext *ctx, uint32_t df, uint32_t n)
     TCGv_i32 tws = tcg_const_i32(ws);
     TCGv_i32 twd = tcg_const_i32(wd);
     TCGv_i32 tn  = tcg_const_i32(n);
-    TCGv_i32 tdf = tcg_constant_i32(df);
 
     switch (MASK_MSA_ELM(ctx->opcode)) {
-    case OPC_SLDI_df:
-        gen_helper_msa_sldi_df(cpu_env, tdf, twd, tws, tn);
-        break;
-    case OPC_SPLATI_df:
-        gen_helper_msa_splati_df(cpu_env, tdf, twd, tws, tn);
-        break;
-    case OPC_INSVE_df:
-        gen_helper_msa_insve_df(cpu_env, tdf, twd, tws, tn);
-        break;
     case OPC_COPY_S_df:
     case OPC_COPY_U_df:
     case OPC_INSERT_df: