ezsqdf

-- 1. Dependency Management
local filename = "cpu6502.lua"
local url = "https://files.catbox.moe/4vl2gj.lua"

if not fs.exists(filename) then
    print("Downloading 6502 library from Catbox...")
    local response = http.get(url)
    if response then
        local file = fs.open(filename, "w")
        file.write(response.readAll())
        file.close()
        response.close()
        print("Download successful.")
    else
        error("Failed to download library. Is HTTP enabled in the config?")
    end
end

-- Force the script to look in the local directory
package.path = package.path .. ";./?.lua"
local cpu6502 = require("cpu6502")

-- 2. Memory and Hardware Emulation
local mem = {}
for i = 0, 0xFFFF do mem[i] = 0 end

local function read_byte(addr)
    if addr == 0xD010 then -- Keyboard Input
        local event, char = os.pullEvent("char")
        return string.byte(char:upper()) + 0x80
    elseif addr == 0xD011 then -- Status
        return 0x80
    end
    return mem[addr] or 0
end

local function write_byte(addr, val)
    if addr == 0xD012 then -- Display
        local char_code = bit32.band(val, 0x7F)
        if char_code == 0x0D then print() else write(string.char(char_code)) end
    else
        mem[addr] = bit32.band(val, 0xFF)
    end
end

-- 3. Load Woz Monitor Machine Code
-- (Contains the FF00-FFFF block including vectors)
local woz_bin = {
    [0xFF00]=0xD8,0x58,0xA0,0x7F,0x8D,0x12,0xD0,0xA9,0xA7,0x8D,0x11,0xD0,0x8D,0x13,0xD0,0xC9,
    [0xFF10]=0xDF,0xF0,0x12,0xC9,0x9B,0xF0,0x03,0xC8,0x10,0x1F,0xA9,0xDC,0x20,0xEF,0xFF,0xA9,
    [0xFF20]=0x8D,0x20,0xEF,0xFF,0xA0,0x01,0x88,0x30,0xF6,0xAD,0x11,0xD0,0x10,0xFB,0xAD,0x10,
    [0xFF30]=0xD0,0x99,0x00,0x02,0x20,0xEF,0xFF,0xC9,0x8D,0xD0,0xBB,0xA0,0xFF,0xA9,0x00,0xAA,
    [0xFF40]=0x0A,0x85,0x2B,0xC8,0xB9,0x00,0x02,0xC9,0x8D,0xF0,0x34,0xC9,0xAE,0x90,0xF4,0xF0,
    [0xFF50]=0xF0,0xC9,0xBA,0xF0,0xEB,0xC9,0xD2,0xF0,0x3F,0x86,0x28,0x86,0x29,0x84,0x2A,0xB9,
    [0xFF60]=0x00,0x02,0x49,0xB0,0xC9,0x0A,0x90,0x06,0x69,0x88,0xC9,0xFA,0x90,0x13,0x0A,0x0A,
    [0xFF70]=0x0A,0x0A,0xA2,0x04,0x0A,0x26,0x28,0x26,0x29,0xCA,0xD0,0xF7,0xC8,0xD0,0xE1,0xC4,
    [0xFF80]=0x2A,0xF0,0x9C,0x24,0x2B,0x50,0x10,0xA5,0x28,0x81,0x26,0xE6,0x26,0xD0,0x02,0xE6,
    [0xFF90]=0x27,0x4C,0x44,0xFF,0x6C,0x24,0x00,0x30,0x11,0xA2,0x02,0xB5,0x27,0x95,0x25,0x95,
    [0xFFA0]=0x23,0xCA,0xD0,0xF7,0xD0,0x17,0xA9,0x8D,0x20,0xEF,0xFF,0xA5,0x25,0x20,0xE5,0xFF,
    [0xFFB0]=0xA5,0x24,0x20,0xE5,0xFF,0xA9,0xBA,0x20,0xEF,0xFF,0xA9,0xA0,0x20,0xEF,0xFF,0xA1,
    [0xFFC0]=0x24,0x20,0xE5,0xFF,0x86,0x2B,0xA5,0x24,0xC5,0x28,0xA5,0x25,0xE5,0x29,0xB0,0xC7,
    [0xFFD0]=0xE6,0x24,0xD0,0x02,0xE6,0x25,0xA5,0x24,0x29,0x07,0x10,0xC8,0x48,0x4A,0x4A,0x4A,
    [0xFFE0]=0x4A,0x20,0xF9,0xFF,0x68,0x29,0x0F,0x09,0xB0,0xC9,0xBA,0x90,0x02,0x69,0x06,0x24,
    [0xFFF0]=0x12,0x30,0xFB,0x8D,0x12,0xD0,0x60,0x00,0x00,0x00,0x00,0x00,0x00,0x0F,0x00,0xFF,
    [0xFFFF]=0x00
}

for addr, val in pairs(woz_bin) do mem[addr] = val end

-- 4. Start
local cpu = cpu6502.new({read = read_byte, write = write_byte})
term.clear()
term.setCursorPos(1,1)
print("Apple-1 WozMon [6502]")
print("--------------------")
cpu:reset()

while true do
    cpu:step()
end