diff --git a/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD_x86_64.cpp b/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD_x86_64.cpp
--- a/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD_x86_64.cpp
+++ b/lldb/source/Plugins/Process/NetBSD/NativeRegisterContextNetBSD_x86_64.cpp
@@ -539,19 +539,19 @@
     reg_value = (uint64_t)m_gpr.regs[_REG_CS];
     break;
   case lldb_fs_x86_64:
-    reg_value = (uint64_t)m_gpr.regs[_REG_FS];
+    reg_value = (uint16_t)m_gpr.regs[_REG_FS];
     break;
   case lldb_gs_x86_64:
-    reg_value = (uint64_t)m_gpr.regs[_REG_GS];
+    reg_value = (uint16_t)m_gpr.regs[_REG_GS];
     break;
   case lldb_ss_x86_64:
     reg_value = (uint64_t)m_gpr.regs[_REG_SS];
     break;
   case lldb_ds_x86_64:
-    reg_value = (uint64_t)m_gpr.regs[_REG_DS];
+    reg_value = (uint16_t)m_gpr.regs[_REG_DS];
     break;
   case lldb_es_x86_64:
-    reg_value = (uint64_t)m_gpr.regs[_REG_ES];
+    reg_value = (uint16_t)m_gpr.regs[_REG_ES];
     break;
 #else
   case lldb_rax_x86_64:
@@ -588,19 +588,19 @@
     reg_value = (uint32_t)m_gpr.r_cs;
     break;
   case lldb_fs_x86_64:
-    reg_value = (uint32_t)m_gpr.r_fs;
+    reg_value = (uint16_t)m_gpr.r_fs;
     break;
   case lldb_gs_x86_64:
-    reg_value = (uint32_t)m_gpr.r_gs;
+    reg_value = (uint16_t)m_gpr.r_gs;
     break;
   case lldb_ss_x86_64:
     reg_value = (uint32_t)m_gpr.r_ss;
     break;
   case lldb_ds_x86_64:
-    reg_value = (uint32_t)m_gpr.r_ds;
+    reg_value = (uint16_t)m_gpr.r_ds;
     break;
   case lldb_es_x86_64:
-    reg_value = (uint32_t)m_gpr.r_es;
+    reg_value = (uint16_t)m_gpr.r_es;
     break;
 #endif
   case lldb_fctrl_x86_64:
@@ -830,19 +830,19 @@
     m_gpr.regs[_REG_CS] = reg_value.GetAsUInt64();
     break;
   case lldb_fs_x86_64:
-    m_gpr.regs[_REG_FS] = reg_value.GetAsUInt64();
+    m_gpr.regs[_REG_FS] = reg_value.GetAsUInt16();
     break;
   case lldb_gs_x86_64:
-    m_gpr.regs[_REG_GS] = reg_value.GetAsUInt64();
+    m_gpr.regs[_REG_GS] = reg_value.GetAsUInt16();
     break;
   case lldb_ss_x86_64:
     m_gpr.regs[_REG_SS] = reg_value.GetAsUInt64();
     break;
   case lldb_ds_x86_64:
-    m_gpr.regs[_REG_DS] = reg_value.GetAsUInt64();
+    m_gpr.regs[_REG_DS] = reg_value.GetAsUInt16();
     break;
   case lldb_es_x86_64:
-    m_gpr.regs[_REG_ES] = reg_value.GetAsUInt64();
+    m_gpr.regs[_REG_ES] = reg_value.GetAsUInt16();
     break;
 #else
   case lldb_rax_x86_64:
@@ -879,19 +879,19 @@
     m_gpr.r_cs = reg_value.GetAsUInt32();
     break;
   case lldb_fs_x86_64:
-    m_gpr.r_fs = reg_value.GetAsUInt32();
+    m_gpr.r_fs = reg_value.GetAsUInt16();
     break;
   case lldb_gs_x86_64:
-    m_gpr.r_gs = reg_value.GetAsUInt32();
+    m_gpr.r_gs = reg_value.GetAsUInt16();
     break;
   case lldb_ss_x86_64:
     m_gpr.r_ss = reg_value.GetAsUInt32();
     break;
   case lldb_ds_x86_64:
-    m_gpr.r_ds = reg_value.GetAsUInt32();
+    m_gpr.r_ds = reg_value.GetAsUInt16();
     break;
   case lldb_es_x86_64:
-    m_gpr.r_es = reg_value.GetAsUInt32();
+    m_gpr.r_es = reg_value.GetAsUInt16();
     break;
 #endif
   case lldb_fctrl_x86_64: