ref: 53f1619831b9695c7b28a4949c7a2f6c177a8392
dir: /syscall-osx.s/
.globl _std$syscall
_std$syscall:
popl %ecx /* return address */
popl %eax /* call num */
pushl %ecx
int $0x80
pushl %ecx /* put the return address back */
ret