diff --git a/rtl/linux/x86_64/si_c.inc b/rtl/linux/x86_64/si_c.inc
index 25c9541c26..f6a60de44c 100644
--- a/rtl/linux/x86_64/si_c.inc
+++ b/rtl/linux/x86_64/si_c.inc
@@ -128,7 +128,8 @@ procedure _FPC_libc_start; assembler; nostackframe; public name '_start';
 {$ifdef FPC_HAS_INDIRECT_ENTRY_INFORMATION}
     movq SysInitEntryInformation@GOTPCREL(%rip),%rcx
 
-    movl %rsi,TEntryInformation.OS.argc(%rcx)
+    { argc is longint in EntryInformation, thus use %edi register }
+    movl %esi,TEntryInformation.OS.argc(%rcx)
     movq %rsp,TEntryInformation.OS.argv(%rcx)
     movq %rsp,(%rax)
     leaq 8(,%rsi,8),%rax
diff --git a/rtl/linux/x86_64/si_g.inc b/rtl/linux/x86_64/si_g.inc
index 5002526582..483bfbdc2a 100644
--- a/rtl/linux/x86_64/si_g.inc
+++ b/rtl/linux/x86_64/si_g.inc
@@ -93,7 +93,8 @@ procedure ini_dummy;
 {$ifdef FPC_HAS_INDIRECT_ENTRY_INFORMATION}
     movq SysInitEntryInformation@GOTPCREL(%rip),%rcx
 
-    movl %rsi,TEntryInformation.OS.argc(%rcx)
+    { argc is longint in EntryInformation, thus use %edi register }
+    movl %esi,TEntryInformation.OS.argc(%rcx)
     movq %rsp,TEntryInformation.OS.argv(%rcx)
     movq %rsp,(%rax)
     leaq 8(,%rsi,8),%rax