target/mips: Add emulation of MXU instructions Q8MUL and Q8MULSU

Adds support for emulating the Q8MUL and Q8MULSU MXU instructions.
Reviewed-by: NAleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: NCraig Janeczek <jancraig@amazon.com>
Signed-off-by: NAleksandar Markovic <amarkovic@wavecomp.com>

target/mips/translate.c

@@ -24323,6 +24323,99 @@ static void gen_mxu_d16mac(DisasContext *ctx)
     tcg_temp_free(t3);
 }
 
+/*
+ * Q8MUL   XRa, XRb, XRc, XRd - Parallel unsigned 8 bit pattern multiply
+ * Q8MULSU XRa, XRb, XRc, XRd - Parallel signed 8 bit pattern multiply
+ */
+static void gen_mxu_q8mul_q8mulsu(DisasContext *ctx)
+{
+    TCGv t0, t1, t2, t3, t4, t5, t6, t7;
+    TCGLabel *l0;
+    uint32_t XRa, XRb, XRc, XRd, sel;
+
+    t0 = tcg_temp_new();
+    t1 = tcg_temp_new();
+    t2 = tcg_temp_new();
+    t3 = tcg_temp_new();
+    t4 = tcg_temp_new();
+    t5 = tcg_temp_new();
+    t6 = tcg_temp_new();
+    t7 = tcg_temp_new();
+
+    l0 = gen_new_label();
+
+    XRa = extract32(ctx->opcode, 6, 4);
+    XRb = extract32(ctx->opcode, 10, 4);
+    XRc = extract32(ctx->opcode, 14, 4);
+    XRd = extract32(ctx->opcode, 18, 4);
+    sel = extract32(ctx->opcode, 22, 2);
+
+    gen_load_mxu_cr(t0);
+    tcg_gen_andi_tl(t0, t0, MXU_CR_MXU_EN);
+    tcg_gen_brcondi_tl(TCG_COND_NE, t0, MXU_CR_MXU_EN, l0);
+
+    gen_load_mxu_gpr(t3, XRb);
+    gen_load_mxu_gpr(t7, XRc);
+
+    if (sel == 0x2) {
+        /* Q8MULSU */
+        tcg_gen_ext8s_tl(t0, t3);
+        tcg_gen_shri_tl(t3, t3, 8);
+        tcg_gen_ext8s_tl(t1, t3);
+        tcg_gen_shri_tl(t3, t3, 8);
+        tcg_gen_ext8s_tl(t2, t3);
+        tcg_gen_shri_tl(t3, t3, 8);
+        tcg_gen_ext8s_tl(t3, t3);
+    } else {
+        /* Q8MUL */
+        tcg_gen_ext8u_tl(t0, t3);
+        tcg_gen_shri_tl(t3, t3, 8);
+        tcg_gen_ext8u_tl(t1, t3);
+        tcg_gen_shri_tl(t3, t3, 8);
+        tcg_gen_ext8u_tl(t2, t3);
+        tcg_gen_shri_tl(t3, t3, 8);
+        tcg_gen_ext8u_tl(t3, t3);
+    }
+
+    tcg_gen_ext8u_tl(t4, t7);
+    tcg_gen_shri_tl(t7, t7, 8);
+    tcg_gen_ext8u_tl(t5, t7);
+    tcg_gen_shri_tl(t7, t7, 8);
+    tcg_gen_ext8u_tl(t6, t7);
+    tcg_gen_shri_tl(t7, t7, 8);
+    tcg_gen_ext8u_tl(t7, t7);
+
+    tcg_gen_mul_tl(t0, t0, t4);
+    tcg_gen_mul_tl(t1, t1, t5);
+    tcg_gen_mul_tl(t2, t2, t6);
+    tcg_gen_mul_tl(t3, t3, t7);
+
+    tcg_gen_andi_tl(t0, t0, 0xFFFF);
+    tcg_gen_andi_tl(t1, t1, 0xFFFF);
+    tcg_gen_andi_tl(t2, t2, 0xFFFF);
+    tcg_gen_andi_tl(t3, t3, 0xFFFF);
+
+    tcg_gen_shli_tl(t1, t1, 16);
+    tcg_gen_shli_tl(t3, t3, 16);
+
+    tcg_gen_or_tl(t0, t0, t1);
+    tcg_gen_or_tl(t1, t2, t3);
+
+    gen_store_mxu_gpr(t0, XRd);
+    gen_store_mxu_gpr(t1, XRa);
+
+    gen_set_label(l0);
+
+    tcg_temp_free(t0);
+    tcg_temp_free(t1);
+    tcg_temp_free(t2);
+    tcg_temp_free(t3);
+    tcg_temp_free(t4);
+    tcg_temp_free(t5);
+    tcg_temp_free(t6);
+    tcg_temp_free(t7);
+}
+
 
 /*
  * Decoding engine for MXU
@@ -25114,14 +25207,8 @@ static void decode_opc_mxu__pool18(CPUMIPSState *env, DisasContext *ctx)
 
     switch (opcode) {
     case OPC_MXU_Q8MUL:
-        /* TODO: Implement emulation of Q8MUL instruction. */
-        MIPS_INVAL("OPC_MXU_Q8MUL");
-        generate_exception_end(ctx, EXCP_RI);
-        break;
     case OPC_MXU_Q8MULSU:
-        /* TODO: Implement emulation of Q8MULSU instruction. */
-        MIPS_INVAL("OPC_MXU_Q8MULSU");
-        generate_exception_end(ctx, EXCP_RI);
+        gen_mxu_q8mul_q8mulsu(ctx);
         break;
     default:
         MIPS_INVAL("decode_opc_mxu");