%include "simple_io.inc"

global  asm_main

SECTION .data
err1: db "incorrect number of command line arguments",10,0
err2: db "incorrect length of  argument",10,0
err3: db "incorrect first letter of argument (should be 3 or 5 or 7 or 9)",10,0
err4: db "incorrect second letter of argument (should be an upper case letter)", 10,0
sizeparam: db "size is: ", 10, 0
letterparam: db "letter is: ", 10,0

SECTION .bss

SECTION .text

;recieves parameters: letter in [RBP+24], number in [RBP+32]
display_shape:
	enter 0, 0
	saveregs
	mov rax, sizeparam
        call print_string
        mov rax, [RBP+32]
	call print_int
	call print_nl
	mov rax, letterparam
	call print_string
	mov rax, [rbp+24]
	call print_char
	call print_nl
	restoregs
	leave
	ret

asm_main:
    enter	0,0             ; setup routine
    saveregs              ; save all registers

	;; the first param is in rdi, so rdi=argc
	cmp	rdi, qword 2         ; argc should be 2
    	jne ERR1

    	;; check length here
	mov 	rbx, qword 0
	mov	rbx, [rsi+8]
	mov	al, byte  [rbx+2]
	cmp 	al, byte 0
	jne 	ERR2

	;; check if first char is a digit
	mov r12, qword 0
	mov r12b, byte [rbx]

	cmp   r12, 48     ; compare al to the ASCII value of '1'
	jb    ERR3        ; error if ASCII value is less than '1' = 31h
	cmp   r12, 57     ; compare al to the ASCII value of '9'
 	ja    ERR3

	;; must be above one and odd
	sub r12, 48	;convert char to number
	cmp r12, 3
	jl ERR3 	; can't be less than 3
	cmp r12, 4 	; cant be even
	je ERR3
	cmp r12, 6 	; cant be even
	je ERR3
	cmp r12, 8 	; cant be even
	je ERR3

	;; second char must be upper case letter
	mov r11, qword 0
	mov r11b, byte [rbx+1] ;contains the second char

	;; checks if second char is upper case letter
	cmp r11, 65
	jb ERR4
	cmp r11, 90
	ja ERR4

	push r12
	push r11
	sub  rsp, 8
	call display_shape
	add  rsp, 8
	pop  r11
	pop  r12


   jmp asm_main_end

 ERR1:
   mov rax, err1
   call print_string
   jmp asm_main_end

 ERR2:
   mov rax, err2
   call print_string
   jmp asm_main_end

 ERR3:
	mov rax, err3
	call print_string
	jmp asm_main_end

 ERR4:
	mov rax, err4
	call print_string
	jmp asm_main_end

 asm_main_end:
   restoregs                  ; restore all registers
   leave
   ret