videochargen/frame.cpp

/*  frame.cpp
 *  Takes a black/white (1bpp) PNM ASCII-armored image as input,
 *  and produces the frame.S assembly code to draw it
 *  as an analog video signal for this project's kernel.
 * */
#include <iostream>
#include <fstream>

enum ExitStatus {
    BAD_ARGUMENT = 1,
    FILE_NOT_OPEN = 2,
    FILE_BAD_FORMAT = 3
};

int main(int argc, char** argv) {
    if (argc != 2) {
        return BAD_ARGUMENT;
    }

    std::fstream infile;
    infile.open(argv[1], std::ios::in);
    if (! infile) {
        return FILE_NOT_OPEN;
    }

    std::fstream outfile;
    outfile.open("frame.S", std::ios::out);
    if (! outfile) {
        return FILE_NOT_OPEN;
    }

    outfile << "#include \"macro.h\"" << std::endl;
    outfile << "#include <avr/io.h>" << std::endl;

    outfile << ".global line_jump_table" << std::endl;
    outfile << "line_jump_table:" << std::endl;
    for (int i = 0; i < 256; ++i) {
        outfile << '\t' << "jmp line_" << i << std::endl;
    }

    int width, height;
    std::string format;
    char c;

    getline(infile, format);

    std::cout << format << std::endl;

    if (format != "P1") {
        return FILE_BAD_FORMAT;
    }

    // skip one line TODO
    getline(infile, format);
    std::cout << format << std::endl;

    infile >> width >> height;
    std::cout << width << " x " << height << std::endl;

    char* image = new char[height * width];

    for (int y = 0; y < height; ) {
        for (int x = 0; x < width; ) {
            c = infile.get();
            if (! infile.good())
                return FILE_BAD_FORMAT;
            if (c == '0' || c == '1') {
                image[y * width + x] = c;
                x++;
            } else {
                continue;
            }
        }
        y++;
    }

    infile.close();

    for (int y = 0; y < height; ++y) {
        outfile << "line_" << y << ":" << std::endl;

        int count = 0;
        char last = image[y * width + 0];

        for (int x = 0; x < width; ++x) {
            char current = image[y * width + x];
            std::cout << "current " << current << " last " << last << std::endl;
            if (current == last) {
                ++count;
            } else {
                std::cout << "detected change" << std::endl;
                if (last == '0') {
                    std::cout << "clear" << std::endl;
                    outfile << '\t' << "cbi IO(PORTB), 4" << std::endl;
                } else if (last == '1') {
                    std::cout << "set" << std::endl;
                    outfile << '\t' << "sbi IO(PORTB), 4" << std::endl;
                }

                if (count > 1) {
                    outfile << '\t' << "ldi r31, " << count - 1 << std::endl;
                    outfile << "1:" << std::endl;
                    outfile << '\t' << "dec r31" << std::endl;
                    outfile << '\t' << "nop" << std::endl;
                    outfile << '\t' << "brne 1b" << std::endl;
                }

                outfile << '\t' << "rjmp 2f" << std::endl;
                outfile << "2:" << std::endl;

                last = current;
                count = 1;
            }


        }

        outfile << '\t' << "cbi IO(PORTB), 4" << std::endl;
        outfile << '\t' << "jmp jump_table_return_address" << std::endl;
    }


    outfile.close();
}