1 files changed, 21 insertions, 0 deletions
diff --git a/sys/rt/amd64/crt1.s b/sys/rt/amd64/crt1.s
new file mode 100644
index 0000000..aaad0ba
--- /dev/null
+++ b/sys/rt/amd64/crt1.s
@@ -0,0 +1,21 @@
+global  _start
+
+; NOTE: assumes program loader has put argc, argv, envc, envp on stack
+section .text
+_start:
+    xor rbp,rbp    ; base pointer undefined: set to 0
+    mov r9,rdx     ; 6th arg: function to register with atexit()
+    pop rsi        ; 2nd arg: argc
+    mov rdx,rsp    ; 3rd arg: argv
+    and rsp,$-16   ; align stack pointer to 16 bytes
+    mov $_fini,r8  ; 5th arg: fini
+    mov $_init,rcx ; 4th arg: init
+    mov $main,rdi  ; 1st arg: main
+
+    call rt·boot   ; int boot(
+                   ;       int(*main)(int,char*[],char*[]),
+                   ;       int argc,
+                   ;       char *argv[],
+                   ;       init, fini, atexit);
+
+.loop: jmp .loop  ; should never reach...