global _start

section .data

format:     db "I %s %x %d%%%c%b", 10, 0
string:     db "love", 0
buf: resb 64d

section .text

%define NEXT_PARAM R8
%define NEXT_FORMAT_SYMBOL RBP
%define BUFFER_SIZE RBX

%macro printf 1-*           ;macro with undefined qty of params
    %rep %0                 ;loop at all parameters
        %rotate -1          ;%1 now is the last parameter
        push %1             ;push last param into stack
    %endrep
    call handle

%endmacro

_start:
        xor BUFFER_SIZE, BUFFER_SIZE
        printf format, string, 3802, 100, '!', 127

handle:
        mov NEXT_PARAM, RSP
        add NEXT_PARAM, 8                       ;[NEXT_PARAM] now is the last pushed arg -- format address
        mov NEXT_FORMAT_SYMBOL, [NEXT_PARAM]    ;NEXT_FORMAT_SYMBOL points to current format symbol
        add NEXT_PARAM, 8                       ;NEXT_PARAM is current arg

        dec NEXT_FORMAT_SYMBOL
next:
        inc NEXT_FORMAT_SYMBOL

        cmp byte [NEXT_FORMAT_SYMBOL], 0        ;program ends by 0-symbol in format string
        je end_program

        cmp byte [NEXT_FORMAT_SYMBOL], '%'      ;if not '%' print source format symbol
        jne simple

        inc NEXT_FORMAT_SYMBOL


        ;switch case
        cmp byte [NEXT_FORMAT_SYMBOL], '%'      ;case %%
        je simple

        cmp byte [NEXT_FORMAT_SYMBOL], 'c'
        je print_char

        cmp byte [NEXT_FORMAT_SYMBOL], 's'
        je print_string

        cmp byte [NEXT_FORMAT_SYMBOL], 'd'
        je print_decimal

        cmp byte [NEXT_FORMAT_SYMBOL], 'b'
        je print_binary

        cmp byte [NEXT_FORMAT_SYMBOL], 'o'
        je print_octal

        cmp byte [NEXT_FORMAT_SYMBOL], 'x'
        je print_hex
;===================================================\
;adds next format string symbol to buffer
;===================================================|
simple:
        mov RAX, [NEXT_FORMAT_SYMBOL]
        call to_buf
        jmp next
;===================================================/



;===================================================\
;adds a char located in next param to buffer
;===================================================|
print_char:
        mov RAX, [NEXT_PARAM]
        add NEXT_PARAM, 8
        call to_buf
        jmp next
;===================================================/




;===================================================\
;adds string to buffer
;===================================================|
print_string:
        mov RSI, [NEXT_PARAM]
        add NEXT_PARAM, 8
.str_loop:
        mov AL, [RSI]
        cmp AL, 0
        je next

        call to_buf
        inc RSI
        jmp .str_loop
;===================================================/


;===================================================\
;puts next agr as binary number to buf
;ENTRY: RAX -- value
;       CL -- base (degree of 2)
;DESTR: R13, R14, CH
;===================================================|
print_binary:
        mov RAX, [NEXT_PARAM]
        add NEXT_PARAM, 8
        mov CL, 1
        call print_degree
        jmp next
;===================================================/


;===================================================\
;puts next agr as octal number to buf
;ENTRY: RAX -- value
;       CL -- base (degree of 2)
;DESTR: R13, R14, CH
;===================================================|
print_octal:
        mov RAX, [NEXT_PARAM]
        add NEXT_PARAM, 8
        mov CL, 3
        call print_degree
        jmp next
;===================================================/

;===================================================\
;puts next agr as hex number to buf
;ENTRY: RAX -- value
;       CL -- base (degree of 2)
;DESTR: R13, R14, CH
;===================================================|
print_hex:
        mov RAX, [NEXT_PARAM]
        add NEXT_PARAM, 8
        mov CL, 4
        call print_degree
        jmp next
;===================================================/

;===================================================\
;ENTRY: RAX -- value
;       CL -- base (degree of 2)
;DESTR: R13, R14, CH
;===================================================|
print_degree:
        mov CH, CL
        xor R13, R13            ;R13 -- corresponding base
.prepare_base:
        shl R13, 1
        inc R13
        dec CH
        cmp CH, 0
        ja .prepare_base

        xor R10, R10            ;R10 -- reversed value
        xor CH, CH              ;counter

.reverse_loop:
        mov R14, RAX
        and R14, R13

        shl R10, cl
        add R10, R14

        shr RAX, CL
        inc CH

        cmp RAX, 0
        jne .reverse_loop

.print_loop:
        mov R14, R10
        and R14, R13

        add R14, '0'

        cmp R14, '9'
        jna .digit
        add R14, 'A' - '0' - 10

.digit:
        mov RAX, R14
        call to_buf

        shr R10, CL
        dec CH
        cmp CH, 0
        jne .print_loop

        ret
;===================================================/


;===================================================\
;adds decimal number to buffer as symbols array
;===================================================|
print_decimal:
        mov RAX, [NEXT_PARAM]
        ;making the mask for last bit
        xor R9, R9
        inc R9
        shl R9, 31d

        ;looking for the sign of the number
        mov R10, [NEXT_PARAM]
        and R10, R9
        cmp R9, R10
        jne .positive_decimal

        ;print minus
        push RAX
        mov RAX, '-'
        call to_buf
        pop RAX

        ;get a positive value from negative
        not RAX
        inc RAX


.positive_decimal:
        mov R9, 10d
        call print_number
        add NEXT_PARAM, 8
        jmp next
;===================================================/

;===================================================\
;Prints a positive decimal number
;ENTRY: R9 -- base
;       RAX -- number to print
;DESTR: CH, R10, R11, RAX
;===================================================|
print_number:
        xor R10, R10            ;reversed value
        xor CH, CH              ;number of digits
        mov R11, RAX

.reverse_loop:

        ;reverse digits in number
        mov RAX, R11
        div R9d

        shl R10, 4              ;log 2 16

        mov R11, RAX
        inc CH

        cmp R11, R9
        jae .reverse_loop

        shl R10, 4
        add R10, R11
        inc CH

.print_loop:
        mov RAX, R10
        and RAX, 1111b
        add RAX, '0'
        call to_buf

        shr R10, 4
        dec CH
        cmp CH, 0
        jne .print_loop

        ret
;===================================================/


;===================================================\
;Puts a symbol into buf
;ENTRY: RAX - char to put
;DESTR: RDI
;===================================================|
to_buf:
        cmp BUFFER_SIZE, 64d
        jae from_buf

        mov RDI, buf
        add RDI, BUFFER_SIZE
        stosb
        inc BUFFER_SIZE

        ret
;===================================================/

;===================================================\
;Prints a buffer's content on a screen
;===================================================|
from_buf:
        push RDX
        push RSI
        cmp BUFFER_SIZE, 0
        je .quit

        mov RDX, BUFFER_SIZE
        mov RSI, buf
        call printf_symbols
        xor BUFFER_SIZE, BUFFER_SIZE
.quit:
        pop RSI
        pop RDX
        ret
;===================================================/

;===================================================\
;prints RDX symbols from [RSI]
;ENTRY: RSI -- symbol address, RDX -- qty of symbols to print
;===================================================|
printf_symbols:
        push RAX
        push RDI

        xor RAX, RAX
        inc RAX

        xor RDI, RDI
        inc RDI

        syscall

        pop RDI
        pop RAX
        ret
;===================================================/

;===================================================\
;ends a program
;===================================================|
end_program:
        call from_buf
        mov RAX, 60
        xor RDI, RDI
        syscall
;===================================================/