shithub: mc

ref: 4db5274a2f6db10e31e11c503f36c85a98c65fbc
dir: /rt/start-freebsd.s/

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.data
/* sys.__cenvp : byte## */
.globl environ
.globl sys$__cenvp
environ:
sys$__cenvp:
	.quad 0

.globl __progname
__progname:
	.quad 0

.globl thread$__tls
thread$__tls:
    .fill 88 /* sizeof(tlshdr) + (8 * sizeof(void#)) = 24 + 64 */

.text
/*
 * The entry point for the whole program.
 * This is called by the OS. In order, it:
 *  - Sets up all argc entries as slices
 *  - Converts argc/argv to a slice
 *  - Stashes a raw envp copy in __cenvp (for syscalls to use)
 *  - Sets up thread local storage for the main thread
 *  - Calls main()
 */
.globl _start
_start:
	andq	$-16,%rsp		/* align the stack pointer */

	/* load argc, argv, envp from stack */
	movq	(%rdi),%rax		/* argc */
	leaq	8(%rdi),%rbx		/* argv */
	movq	(%rbx),%rcx		/* save progname */
	movq	%rcx,__progname
	leaq	16(%rdi,%rax,8),%rcx	/* envp = argv + 8*argc + 8 */

	/* store envp for some syscalls to use without converting */
	movq    %rcx,sys$__cenvp(%rip)

	/* stack allocate sizeof(byte[:])*argc */
	imulq	$16,%rax,%rdx
	subq	%rdx,%rsp
	movq	%rsp,%rcx		/* args[:] */

	/* convert argc, argv to byte[:][:] for args. */
	pushq	%rax
	pushq	%rcx
	call	cvt

	/* set up the intial tls region for the main thread */
	subq	$0x10,%rsp
	movq	$165,%rax		/* sysarch */
	movq	$129,%rdi		/* Archamd64setfs */
	leaq	thread$__tls(%rip),%rsi
	movq	%rsi,(%rsp)
	movq	%rsp,%rsi
	syscall
	addq	$0x10,%rsp

	xorq %rbp,%rbp

	call	__init__
	call	main
	call	__fini__

	/* exit(0) */
	xorq	%rdi,%rdi
	movq	$1,%rax
	syscall