Implement x86 debug registers

src/cpu/386_common.c

@@ -80,6 +80,7 @@ int smm_in_hlt  = 0;
 int smi_block   = 0;
 
 int prefetch_prefixes = 0;
+int rf_flag_no_clear = 0;
 
 int tempc;
 int oldcpl;
@@ -1655,6 +1656,38 @@ cpu_386_flags_rebuild(void)
     flags_rebuild();
 }
 
+int
+cpu_386_check_instruction_fault(void)
+{
+    int i = 0;
+    int fault = 0;
+    /* Report no fault if RF is set. */
+    if (cpu_state.eflags & RF_FLAG)
+        return 0;
+
+    /* Make sure breakpoints are enabled. */
+    if (!(dr[7] & 0xFF))
+        return 0;
+
+    for (i = 0; i < 4; i++) {
+        int breakpoint_enabled = !!(dr[7] & (0x3 << (2 * i))) && !(dr[7] & (0x30000 << (4 * i)));
+        uint64_t translated_addr = 0xffffffffffffffffULL;
+        if (!breakpoint_enabled)
+            continue;
+        if (!(cr0 >> 31))
+            translated_addr = dr[i];
+        else
+            translated_addr = mmutranslate_noabrt(dr[i], 0);
+        
+        if ((cs + cpu_state.pc) == translated_addr) {
+            dr[6] |= (1 << i);
+            fault = 1;
+        }
+    }
+
+    return fault;
+}
+
 int
 sysenter(uint32_t fetchdat)
 {