Add build system scaffolding and libc headers

1 files changed, 17 insertions, 0 deletions

diff --git a/lib/libc/arch/x86_64/setjmp.c b/lib/libc/arch/x86_64/setjmp.c
new file mode 100644
index 00000000..d268ae25
--- /dev/null
+++ b/lib/libc/arch/x86_64/setjmp.c
@@ -0,0 +1,17 @@
+#include <setjmp.h>
+
+__attribute__((naked, returns_twice)) int setjmp(jmp_buf env)
+{
+	__asm__ __volatile__("mov %rbx,(%rdi)\n"
+			     "mov %rbp,8(%rdi)\n"
+			     "mov %r12,16(%rdi)\n"
+			     "mov %r13,24(%rdi)\n"
+			     "mov %r14,32(%rdi)\n"
+			     "mov %r15,40(%rdi)\n"
+			     "lea 8(%rsp),%rdx\n"
+			     "mov %rdx,48(%rdi)\n"
+			     "mov (%rsp),%rdx\n"
+			     "mov %rdx,56(%rdi)\n"
+			     "xor %eax,%eax\n"
+			     "ret\n");
+}