target/mips: Add emulation of MXU instructions S32I2M and S32M2I

Add support for emulating the S32I2M and S32M2I MXU instructions.
This commit also contains utility functions for reading/writing
to MXU registers. This is required for overall MXU instruction
support.

Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: Craig Janeczek <jancraig@amazon.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>

target/mips/translate.c

@@ -2569,6 +2569,36 @@ static inline void gen_store_srsgpr (int from, int to)
     }
 }
 
+/* MXU General purpose registers moves. */
+static inline void gen_load_mxu_gpr(TCGv t, unsigned int reg)
+{
+    if (reg == 0) {
+        tcg_gen_movi_tl(t, 0);
+    } else if (reg <= 15) {
+        tcg_gen_mov_tl(t, mxu_gpr[reg - 1]);
+    }
+}
+
+static inline void gen_store_mxu_gpr(TCGv t, unsigned int reg)
+{
+    if (reg > 0 && reg <= 15) {
+        tcg_gen_mov_tl(mxu_gpr[reg - 1], t);
+    }
+}
+
+/* MXU control register moves. */
+static inline void gen_load_mxu_cr(TCGv t)
+{
+    tcg_gen_mov_tl(t, mxu_CR);
+}
+
+static inline void gen_store_mxu_cr(TCGv t)
+{
+    /* TODO: Add handling of RW rules for MXU_CR. */
+    tcg_gen_mov_tl(mxu_CR, t);
+}
+
+
 /* Tests */
 static inline void gen_save_pc(target_ulong pc)
 {
@@ -24012,6 +24042,59 @@ static void decode_opc_special(CPUMIPSState *env, DisasContext *ctx)
 #define MXU_OPTN3_PTN7  7
 
 
+/*
+ * S32I2M XRa, rb - Register move from GRF to XRF
+ */
+static void gen_mxu_s32i2m(DisasContext *ctx)
+{
+    TCGv t0;
+    uint32_t XRa, Rb;
+
+    t0 = tcg_temp_new();
+
+    XRa = extract32(ctx->opcode, 6, 5);
+    Rb = extract32(ctx->opcode, 16, 5);
+
+    gen_load_gpr(t0, Rb);
+    if (XRa <= 15) {
+        gen_store_mxu_gpr(t0, XRa);
+    } else if (XRa == 16) {
+        gen_store_mxu_cr(t0);
+    }
+
+    tcg_temp_free(t0);
+}
+
+/*
+ * S32M2I XRa, rb - Register move from XRF to GRF
+ */
+static void gen_mxu_s32m2i(DisasContext *ctx)
+{
+    TCGv t0;
+    uint32_t XRa, Rb;
+
+    t0 = tcg_temp_new();
+
+    XRa = extract32(ctx->opcode, 6, 5);
+    Rb = extract32(ctx->opcode, 16, 5);
+
+    if (XRa <= 15) {
+        gen_load_mxu_gpr(t0, XRa);
+    } else if (XRa == 16) {
+        gen_load_mxu_cr(t0);
+    }
+
+    gen_store_gpr(t0, Rb);
+
+    tcg_temp_free(t0);
+}
+
+
+/*
+ * Decoding engine for MXU
+ * =======================
+ */
+
 /*
  *
  * Decode MXU pool00
@@ -25091,14 +25174,10 @@ static void decode_opc_mxu(CPUMIPSState *env, DisasContext *ctx)
         generate_exception_end(ctx, EXCP_RI);
         break;
     case OPC_MXU_S32M2I:
-        /* TODO: Implement emulation of S32M2I instruction. */
-        MIPS_INVAL("OPC_MXU_S32M2I");
-        generate_exception_end(ctx, EXCP_RI);
+        gen_mxu_s32m2i(ctx);
         break;
     case OPC_MXU_S32I2M:
-        /* TODO: Implement emulation of S32I2M instruction. */
-        MIPS_INVAL("OPC_MXU_S32I2M");
-        generate_exception_end(ctx, EXCP_RI);
+        gen_mxu_s32i2m(ctx);
         break;
     case OPC_MXU_D32SLL:
         /* TODO: Implement emulation of D32SLL instruction. */