;; echo.asm: output the contents of argv, separated by spaces.

BITS 64

	org	0x10000

	mov	edi, 1			; rdi = 1 (constant)
	pop	rbp			; rbp = argc
	pop	rbx			; rbx = argv

	dec	rbp			; argc <= 1?
	jle	done			; yes, quit now

argloop:
	add	rbx, 8			; advance to next arg
	mov	rsi, [rbx]
len:	lodsb
	or	al, al
	jnz	len			; find end of string
	mov	rdx, rsi
	mov	rsi, [rbx]		; rsi = arg pointer
	sub	rdx, rsi
	dec	rdx			; rdx = string length
	mov	eax, edi
	syscall				; write(1, rsi, rdx)
	dec	rbp			; any args left?
	jle	done			; no, exit loop here
	lea	rsi, [rel SPC]
	mov	edx, edi
	mov	eax, edi
	syscall				; write(1, " ", 1)
	jmp	argloop			; and repeat

done:
	lea	rsi, [rel NL]
	mov	edx, edi
	mov	eax, edi
	syscall				; write(1, "\n", 1)
	mov	eax, 60
	xor	edi, edi
	syscall				; exit(0)

SPC:	db	32			; space character
NL:	db	10			; line break