thinking about syscalls and newlib ...

1 files changed, 40 insertions, 0 deletions

diff --git a/interface/crt0.s b/interface/crt0.s
new file mode 100644
index 0000000..ad9884f
--- /dev/null
+++ b/interface/crt0.s
@@ -0,0 +1,40 @@
+.global _start
+
+_start:
+
+# copy reent to this page
+push %ebx
+push %ecx
+
+mov _impure_ptr,%eax
+mov $0xf5000000,%ebx
+copy: 
+mov (%eax),%ecx
+mov %ecx,(%ebx)
+add $4, %ebx
+add $4, %eax
+cmp $0xf5001000,%ebx
+jne copy
+
+pop %ecx
+pop %ebx
+
+# environment adress was passed on stack
+
+movl $0xf5000000, _impure_ptr
+
+pop %eax                      
+mov %eax, environ
+
+
+# call main (argc and argv are on the stack)
+call main
+
+# push exit code and pass to _exit syscall
+push %eax
+call _exit
+
+# this should never be reached!
+.wait:
+    hlt
+jmp .wait