target/mips: Add emulation of nanoMIPS 16-bit shift instructions

Add emulation of nanoMIPS 16-bit shift instructions.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Yongbok Kim <yongbok.kim@mips.com>
Signed-off-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: Stefan Markovic <smarkovic@wavecomp.com>

target/mips/translate.c

@@ -16765,6 +16765,21 @@ static int decode_nanomips_opc(CPUMIPSState *env, DisasContext *ctx)
     case NM_P16_MV:
         break;
     case NM_P16_SHIFT:
+        {
+            int shift = extract32(ctx->opcode, 0, 3);
+            uint32_t opc = 0;
+            shift = (shift == 0) ? 8 : shift;
+
+            switch (extract32(ctx->opcode, 3, 1)) {
+            case NM_SLL16:
+                opc = OPC_SLL;
+                break;
+            case NM_SRL16:
+                opc = OPC_SRL;
+                break;
+            }
+            gen_shift_imm(ctx, opc, rt, rs, shift);
+        }
         break;
     case NM_P16C:
         break;