[v3,14/16] target/mips: Convert microMIPS LI opcode to decodetree

Commit Message

Philippe Mathieu-Daudé Nov. 26, 2024, 2 p.m. UTC

Once the xlat() and simm7() helpers are added,
the decoding is trivial.

Signed-off-by: Philippe Mathieu-Daudé <[e-mail]>
---
 target/mips/tcg/micromips16.decode        |  9 +++++++++
 target/mips/tcg/micromips_translate.c     | 19 +++++++++++++++++++
 target/mips/tcg/micromips_translate.c.inc | 12 +-----------
 3 files changed, 29 insertions(+), 11 deletions(-)

Patch

diff --git a/target/mips/tcg/micromips16.decode b/target/mips/tcg/micromips16.decode
index d341da16b04..fdc3b131c9c 100644
--- a/target/mips/tcg/micromips16.decode
+++ b/target/mips/tcg/micromips16.decode
@@ -9,3 +9,12 @@ 
 #            (Document Number: MD00582)
 #            microMIPS64 Instruction Set
 #            (Document Number: MD00594)
+
+&rd_imm         rd imm
+
+%xlat_rd        7:3 !function=xlat
+%simm7          0:7 !function=simm7
+
+@rd_imm7        ...... ... .......          &rd_imm         rd=%xlat_rd imm=%simm7
+
+LI              111011 ... .......          @rd_imm7        # LI16
diff --git a/target/mips/tcg/micromips_translate.c b/target/mips/tcg/micromips_translate.c
index f0b5dbf655d..198eb466057 100644
--- a/target/mips/tcg/micromips_translate.c
+++ b/target/mips/tcg/micromips_translate.c
@@ -9,11 +9,23 @@ 
 #include "qemu/osdep.h"
 #include "translate.h"
 
+static int xlat(DisasContext *ctx, int x)
+{
+    static const int map[] = { 16, 17, 2, 3, 4, 5, 6, 7 };
+
+    return map[x];
+}
+
 static inline int plus_1(DisasContext *ctx, int x)
 {
     return x + 1;
 }
 
+static inline int simm7(DisasContext *ctx, int x)
+{
+    return x == 0x7f ? -1 : x;
+}
+
 /* Include the auto-generated decoders.  */
 #include "decode-micromips16.c.inc"
 #include "decode-micromips32.c.inc"
@@ -22,3 +34,10 @@  static bool trans_LSA(DisasContext *ctx, arg_r *a)
 {
     return gen_lsa(ctx, a->rd, a->rt, a->rs, a->sa);
 }
+
+static bool trans_LI(DisasContext *ctx, arg_rd_imm *a)
+{
+    gen_li(ctx, a->rd, a->imm);
+
+    return true;
+}
diff --git a/target/mips/tcg/micromips_translate.c.inc b/target/mips/tcg/micromips_translate.c.inc
index 73394554509..cb98d6af7e4 100644
--- a/target/mips/tcg/micromips_translate.c.inc
+++ b/target/mips/tcg/micromips_translate.c.inc
@@ -113,7 +113,6 @@  enum {
     BLTZALC = 0x38,
     BLTUC = 0x38,
     SW16 = 0x3a,
-    LI16 = 0x3b,
     JALX32 = 0x3c,
     JAL32 = 0x3d,
     BLEZC = 0x3d,
@@ -3004,7 +3003,7 @@  static int decode_isa_micromips(CPUMIPSState *env, DisasContext *ctx)
         case 2:
         /* LBU16, LHU16, LWSP16, LW16, SB16, SH16, SWSP16, SW16 */
         case 3:
-        /* MOVE16, ANDI16, POOL16D, POOL16E, BEQZ16, BNEZ16, B16, LI16 */
+        /* MOVE16, ANDI16, POOL16D, POOL16E, BEQZ16, BNEZ16, B16 */
             if (ctx->hflags & MIPS_HFLAG_BDS32) {
                 gen_reserved_instruction(ctx);
                 return 2;
@@ -3214,15 +3213,6 @@  static int decode_isa_micromips(CPUMIPSState *env, DisasContext *ctx)
                            (ctx->insn_flags & ISA_MIPS_R6) ? 0 : 4);
 
         break;
-    case LI16:
-        {
-            int reg = mmreg(uMIPS_RD(ctx->opcode));
-            int imm = ZIMM(ctx->opcode, 0, 7);
-
-            imm = (imm == 0x7f ? -1 : imm);
-            tcg_gen_movi_tl(cpu_gpr[reg], imm);
-        }
-        break;
     case RES_29:
     case RES_31:
     case RES_39: