From cc86e94cd5636b1b83fde08a6a82842d182684d7 Mon Sep 17 00:00:00 2001
From: Yang Liu <numbksco@gmail.com>
Date: Tue, 5 Mar 2024 00:49:57 +0800
Subject: [LA64] Detect the existence of LBT extension (#1325)

---
 src/main.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

(limited to 'src')

diff --git a/src/main.c b/src/main.c
index 5e14b677..fdf4edcd 100644
--- a/src/main.c
+++ b/src/main.c
@@ -445,11 +445,14 @@ HWCAP2_ECV
     if(arm64_afp)
         printf_log(LOG_INFO, " AFP");
 #elif defined(LA64)
-    printf_log(LOG_INFO, "Dynarec for LoongArch");
-    char *p = getenv("BOX64_DYNAREC_LA64NOEXT");
+    printf_log(LOG_INFO, "Dynarec for LoongArch ");
+    char* p = getenv("BOX64_DYNAREC_LA64NOEXT");
     if(p == NULL || p[0] == '0') {
-        // We don't bother to detect it, it's there.
-        la64_lbt = 1;
+        uint32_t cpucfg2 = 0, idx = 2;
+        // there are other extensions, but we don't care.
+        asm volatile("cpucfg %0, %1" : "=r"(cpucfg2) : "r"(idx));
+        if (la64_lbt = (cpucfg2 >> 18) & 0b1)
+            printf_log(LOG_INFO, "with extension LBT_X86");
     }
 #elif defined(RV64)
     void RV64_Detect_Function();
-- 
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