#include <gb/gb.h>
#include "number.h"

#define BUFFER_SIZE 16
UBYTE keyBuffer[BUFFER_SIZE];
UBYTE head, tail, exist;
UBYTE cardinal; //DEC..0 HEX..1 BIN..2
DWORD dec[] = {10000000, 1000000, 100000, 10000, 1000, 100, 10, 1};
DWORD number, mod, stack[10];
UBYTE ans;

void setData(UBYTE data)
{
    UBYTE p;

    p = tail;
    keyBuffer[p++] = data;
    if(p == BUFFER_SIZE)
        p = 0;
    if(p != head)
        tail = p;
    exist = TRUE;
}

UBYTE getData()
{
    UBYTE b;

    if(!exist)
        return 0xFF;

    b = keyBuffer[head++];
    if(head == BUFFER_SIZE)
        head = 0;
    if(head == tail)
        exist = FALSE;

    return b;
}

void bufferClear()
{
    head = 0;
    tail = 0;
    exist = FALSE;
}

void keyCodeReceive()
{
    SC_REG &= 0x7f; //受信停止
    setData(SB_REG);
    SC_REG = 0x80; //受信開始
}

//10進数表示
void decimalDisplay(UBYTE y, DWORD n)
{
    UBYTE i, digit, top = TRUE;
    DWORD num;

    if(n < 0)
    {
        set_bkg_tiles(0, y * 2, 2, 2, number_tiles + 64);
        num = -n;
    }
    else
    {
        num = n;
        set_bkg_tiles(0, y * 2, 2, 2, NULL);
    }

    if(num > 99999999)
        num %= 100000000;

    for(i=0; i!=8; i++) //<、<=、>、>=より==と!=の方が生成コードが短くなる
    {
        digit = num / dec[i];
        num %= dec[i];
        if(digit != 0)
            top = FALSE;
        if(digit == 0 && top)
        {
            if(i != 7)
                set_bkg_tiles(i * 2 + 2, y * 2, 2, 2, 0);
            else
                set_bkg_tiles(i * 2 + 2, y * 2, 2, 2, number_tiles + digit * 4);
        }
        else
            set_bkg_tiles(i * 2 + 2, y * 2, 2, 2, number_tiles + digit * 4);
    }
}

//16進数表示
void hexDisplay(UBYTE y, DWORD n)
{
    UBYTE i, digit, top = TRUE;
    DWORD num;

    num = n & 0xFFFFFFFF;

    for(i=0; i!=8; i++)
    {
        digit = (num >> ((7 - i) * 4)) & 0xF;
        if(digit != 0)
            top = FALSE;
        if(digit == 0 && top)
        {
            if(i != 7)
                set_bkg_tiles(i * 2 + 2, y * 2, 2, 2, 0);
            else
                set_bkg_tiles(i * 2 + 2, y * 2, 2, 2, number_tiles + digit * 4);
        }
        else
            set_bkg_tiles(i * 2 + 2, y * 2, 2, 2, number_tiles + digit * 4);
    }
}

//2進数表示
void binaryDisplay(UBYTE y, DWORD n)
{
    UBYTE i, digit;
    DWORD num;

    num = n & 0xFF;

    for(i=0; i!=8; i++)
    {
        digit = (num >> (7 - i)) & 1;
        set_bkg_tiles(i * 2 + 2, y * 2, 2, 2, number_tiles + digit * 4);
    }
}

void display()
{
    switch(cardinal)
    {
        case 0:
            decimalDisplay(1, number);
            break;
        case 1:
            hexDisplay(1, number);
            break;
        case 2:
            binaryDisplay(1, number);
            break;
    }
}

void displayAll()
{
    switch(cardinal)
    {
        case 0:
            decimalDisplay(1, number);
            decimalDisplay(2, mod);
            decimalDisplay(4, stack[0]);
            decimalDisplay(5, stack[1]);
            decimalDisplay(6, stack[2]);
            decimalDisplay(7, stack[3]);
            break;
        case 1:
            hexDisplay(1, number);
            hexDisplay(2, mod);
            hexDisplay(4, stack[0]);
            hexDisplay(5, stack[1]);
            hexDisplay(6, stack[2]);
            hexDisplay(7, stack[3]);
            break;
        case 2:
            binaryDisplay(1, number);
            binaryDisplay(2, mod);
            binaryDisplay(4, stack[0]);
            binaryDisplay(5, stack[1]);
            binaryDisplay(6, stack[2]);
            binaryDisplay(7, stack[3]);
            break;
    }
}

void push()
{
    UBYTE i;

    for(i=9; i>0; i--)
        stack[i] = stack[i - 1];
    stack[0] = number;
    number = 0;
}

DWORD pop()
{
    DWORD p;
    UBYTE i;

    p = stack[0];
    for(i=0; i<9; i++)
        stack[i] = stack[i + 1];
    stack[9] = 0;

    return p;
}

void div(DWORD n, DWORD d)
{
    //割られる数より割る数の絶対値が大きいとフリーズする
    if((UDWORD)n < (UDWORD)d)
    {
        number = 0;
        if(n < 0)
            mod = -n;
        else
            mod = n;
    }
    else
    {
        number = n / d;
        mod = n % d;
        if(mod < 0)
            mod = -mod;
    }
}

void main()
{
    UBYTE i, keyin;
    DWORD n, w;

    cardinal = 0; //10進数
    ans = FALSE;

    //背景データ収納(数字)
	set_bkg_data(1, number_data_length, number_data);

    //表示初期化
    number = 0;
    mod = 0;
    for(i=0; i!=9; i++)
        stack[i] = 0;
    displayAll();
    
    SHOW_BKG; //背景表示

    bufferClear();

    set_interrupts(SIO_IFLAG);
    add_SIO(keyCodeReceive);

    SC_REG = 0x80; //受信開始(外部クロック)

    while(1)
    {
        if(exist)
        {
            keyin = getData();

            if(keyin < 16) //0〜F
            {
                if(ans)
                {
                    push();
                    displayAll();
                    ans = FALSE;
                }

                n = keyin;
                if(cardinal == 0)
                {
                    if(n < 10) //入力は0〜9
                    {
                        if(number < 0) //マイナス
                        {
                            w = number * 10 - n;
                            if(w > -100000000) //最小値を超えない
                                number = w;
                        }
                        else
                        {
                            w = number * 10 + n;
                            if(w < 100000000) //最大値を超えない
                                number = w;
                        }
                    }
                }
                else if(cardinal == 1)
                {
                    if((number & 0xF0000000) == 0) //最大値を超えない
                    {
                        number <<= 4;
                        number += n;
                    }
                }
                else
                {
                    if(n < 2) //入力は0〜1
                    {
                        if((number & 0x80) == 0) //最大値を超えない
                        {
                            number <<= 1;
                            number += n;
                        }
                    }
                }
                display();
            }
            else
            {
                switch(keyin)
                {
                    case 16: //Enter
                        push();
                        ans = FALSE;
                        break;
                    case 17: //+
                        if(cardinal) //16,2進数
                            number = (UDWORD)pop() + (UDWORD)number;
                        else //10進数
                            number = pop() + number;
                        ans = TRUE;
                        break;
                    case 18: //-
                        if(cardinal) //16,2進数
                            number = (UDWORD)pop() - (UDWORD)number;
                        else //10進数
                            number = pop() - number;
                        ans = TRUE;
                        break;
                    case 19: //*
                        if(cardinal) //16,2進数
                            number = (UDWORD)pop() * (UDWORD)number;
                        else //10進数
                            number = pop() * number;
                        ans = TRUE;
                        break;
                    case 20: //'/'
                        if(number == 0) //0で除算
                            break;
                        if(cardinal) //16,2進数
                        {
                            w = pop();
                            n = number;
                            number = (UDWORD)w / (UDWORD)n;
                            mod = (UDWORD)w % (UDWORD)n;
                        }
                        else //10進数
                            div(pop(), number);
                        ans = TRUE;
                        break;
                    case 21: //OR
                        number = pop() | number;
                        ans = TRUE;
                        break;
                    case 22: //NOT
                        number = ~number;
                        ans = TRUE;
                        break;
                    case 23: //AND
                        number = pop() & number;
                        ans = TRUE;
                        break;
                    case 24: //XOR
                        n = number; //別の変数に代入しないと正しく演算できない
                        number = pop() ^ n;
                        ans = TRUE;
                        break;
                    case 25: //'+/-'
                        if(cardinal == 0)
                            number = -number;
                        break;
                    case 26: //Clear
                        number = 0;
                        ans = FALSE;
                        break;
                    case 27: //Clear Stack
                        number = 0;
                        for(i=0; i!=10; i++)
                            stack[i] =0;
                        ans = FALSE;
                        break;
                    case 28: //Cardinal
                        if(cardinal == 0)
                        {
                            cardinal = 1;
                            for(i=1; i!=8; i++)
                                set_bkg_tiles(0, i * 2, 2, 2, NULL);
                        }
                        else if(cardinal == 1)
                        {
                            cardinal = 2;
                            for(i=1; i!=8; i++)
                                set_bkg_tiles(0, i * 2, 2, 2, NULL);
                        }
                        else
                            cardinal = 0;
                        break;
                }
                displayAll();
                mod = 0;
            }
        }
    }
}