1 files changed, 28 insertions, 0 deletions
diff --git a/kernel/x86.c b/kernel/x86.c
index 782baec..7775ab7 100644
--- a/kernel/x86.c
+++ b/kernel/x86.c
@@ -49,6 +49,10 @@ uint32_t x86_get_cr1()
     return cr;
 }
 
+void x86_mov(uint8_t val)
+{
+}
+
 uint32_t x86_get_cr2()
 {
     uint32_t cr;
@@ -134,4 +138,28 @@ void x86_flush_tlb(uint32_t addr)
     asm volatile("invlpg (%0)" ::"r" (addr) : "memory");
 }
 
+//xchg
+volatile uint8_t x86_xchg(volatile uint8_t *addr, uint8_t val)
+{   
+  uint8_t result;
+
+  // test. because asm does not work !?
+  uint8_t oldval=*addr;
+  *addr=val;
+   return oldval;
+    
+
+  
+  // The + in "+m" denotes a read-modify-write operand.
+  asm volatile("lock xchg %0, %1" :
+               "+m" (*addr), "=a" (result) :
+               "1" (val) :
+               "cc");
+
+ //log(FOOLOS_MODULE_NAME,FOOLOS_LOG_INFO,"xchg val:%d with addr:0x%08X : result: %d",val,addr,result);
+//
+  return result;
+} 
+
+