ref: 96c8217e913d8d6de22bbb1aa3624c26e66838fc
dir: /rt/start-linux.s/
.data /* sys._environment : byte[:][:] */ .globl sys$__environment sys$__environment: .envbase: .quad 0 /* env size */ .envlen: .quad 0 /* env ptr */ .globl sys$__cenvp sys$__cenvp: .quad 0 .text /* * The entry point for the whole program. * This is called by the OS. In order, it: * - Sets up all argc entries as slices * - Sets up all envp entries as slices * - Converts argc/argv to a slice * - Stashes envp in sys._environment * - Stashes a raw envp copy in __cenvp (for syscalls to use) * - Calls main() */ .globl _start _start: /* turn args into a slice */ movq %rsp,%rbp /* stack allocate sizeof(byte[:])*(argc + len(envp)) */ movq (%rbp),%rax leaq 16(%rbp,%rax,8), %rbx /* argp = argv + 8*argc + 8 */ call count addq %r9,%rax imulq $16,%rax subq %rax,%rsp movq %rsp, %rdx /* saved args[:] */ /* stack allocate sizeof(byte[:])*(argc + len(envp)) */ movq (%rbp),%rax leaq 16(%rbp,%rax,8), %rbx /* argp = argv + 8*argc + 8 */ call count addq %r9,%rax imulq $16,%rax subq %rax,%rsp movq %rsp, %rdx /* saved args[:] */ /* convert envp to byte[:][:] for sys._environment */ movq (%rbp),%rax leaq 16(%rbp,%rax,8), %rbx /* envp = argv + 8*argc + 8 */ /* store envp for some syscalls to use without converting */ movq %rbx,sys$__cenvp(%rip) movq %r9,%rax movq %rsp, %rcx movq %r9,.envlen movq %rdx,.envbase call cvt movq %rcx,%rdx /* convert argc, argv to byte[:][:] for args. */ movq (%rbp), %rax /* argc */ leaq 8(%rbp), %rbx /* argv */ movq (%rbp), %rsi /* saved argc */ call cvt pushq %rsi pushq %rdx /* enter the main program */ call main /* exit(0) */ xorq %rdi,%rdi movq $60,%rax syscall