target/loongarch: Add function to check current arch

Add is_la64 function to check if the current cpucfg[1].arch equals to
2(LA64).

Signed-off-by: Jiajie Chen <c@jia.je>
Co-authored-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Song Gao <gaosong@loongson.cn>
Message-ID: <20230817093121.1053890-2-gaosong@loongson.cn>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20230821125959.28666-7-philmd@linaro.org>

target/loongarch/cpu.h

@@ -132,6 +132,11 @@ FIELD(CPUCFG1, HP, 24, 1)
 FIELD(CPUCFG1, IOCSR_BRD, 25, 1)
 FIELD(CPUCFG1, MSG_INT, 26, 1)
 
+/* cpucfg[1].arch */
+#define CPUCFG1_ARCH_LA32R       0
+#define CPUCFG1_ARCH_LA32        1
+#define CPUCFG1_ARCH_LA64        2
+
 /* cpucfg[2] bits */
 FIELD(CPUCFG2, FP, 0, 1)
 FIELD(CPUCFG2, FP_SP, 1, 1)
@@ -421,6 +426,11 @@ static inline int cpu_mmu_index(CPULoongArchState *env, bool ifetch)
 #endif
 }
 
+static inline bool is_la64(CPULoongArchState *env)
+{
+    return FIELD_EX32(env->cpucfg[1], CPUCFG1, ARCH) == CPUCFG1_ARCH_LA64;
+}
+
 /*
  * LoongArch CPUs hardware flags.
  */