calc.asm

%include "io.asm"
%include "memory.asm"
%include "rpn.asm"
%include "strcmp.asm"
%include "tokenize.asm"
%include "winapi.asm"

global main

section .data
    STD_INPUT_HANDLE  equ -10
    STD_OUTPUT_HANDLE equ -11

    INPUT_BUFFER_SIZE equ 1024

    cursor            db "calc>", 0
    cursor.len        equ $-cursor
    test_cmd          db "-- TESTING --", 10, 0
    test_cmd.len      equ $-test_cmd

    ; Commands
    EXIT_COMMAND      db "exit", 0
    TEST_COMMAND      db "?test?", 0

section .bss
    empty             resd 1
    CONSOLE_HANDLE    resq 1

    input_buffer      resb INPUT_BUFFER_SIZE

section .text

main:
    push rbp
    mov rbp, rsp
    sub rsp, 0x30

    call input_loop   ; main loop

    leave
    ret

input_loop:
    call zero_input_buffer

    ; display the input cursor 
    mov rcx, cursor
    mov rdx, cursor.len
    call write_line

    ; read the input
    mov rcx, input_buffer
    mov rdx, INPUT_BUFFER_SIZE
    call read_line

    ; switch (input_buffer)

    ; case "exit"
    mov rcx, input_buffer
    mov rdx, EXIT_COMMAND 
    call strcmp
    test rax, rax
    je end

    ; case "?test?"
    mov rcx, input_buffer
    mov rdx, TEST_COMMAND 
    call strcmp
    test rax, rax
    je test_command

    ; Parse the rest
    mov rcx, input_buffer
    call tokenise
    mov rcx, rax
    call calculate_rpn

input_loop_end:

    jmp input_loop

end:
    mov rcx, 0x00
    call ExitProcess

    ret

; Prints the test command
test_command:
    mov rcx, test_cmd
    mov rdx, test_cmd.len-0x01
    call write_line

    jmp input_loop_end

zero_input_buffer:
    cld
    mov rdi, input_buffer
    mov rcx, INPUT_BUFFER_SIZE

    xor rax, rax
    rep stosb

    ret