Implement scrolling console

src/modules/main/console.cpp

@@ -0,0 +1,109 @@
+#include "console.h"
+
+console::console(const font &f, const screen &s, void *scratch, size_t len) :
+	m_font(f),
+	m_screen(s),
+	m_size(s.width() / f.width(), s.height() / f.height()),
+	m_fg(0xffffffff),
+	m_bg(0x00000000),
+	m_first(0),
+	m_length(len),
+	m_data(static_cast<char *>(scratch))
+{
+	if (len < m_size.size()) {
+		m_data = nullptr;
+	}
+
+	const unsigned count = m_size.size();
+	for (unsigned i = 0; i < count; ++i)
+		m_data[i] = 0;
+	repaint();
+}
+
+char *
+console::line_pointer(unsigned line)
+{
+	if (!m_data) return nullptr;
+	return m_data + ((m_first + line) % m_size.y) * m_size.x;
+}
+
+void
+console::repaint()
+{
+	m_screen.fill(m_bg);
+	if (!m_data) return;
+
+	for (unsigned y = 0; y < m_size.y; ++y) {
+		const char *line = line_pointer(y);
+		for (unsigned x = 0; x < m_size.x; ++x) {
+			m_font.draw_glyph(
+				m_screen,
+				line[x] ? line[x] : ' ',
+				m_fg,
+				m_bg,
+				x * m_font.width(),
+				y * m_font.height());
+		}
+	}
+}
+
+void
+console::scroll(unsigned lines)
+{
+	if (!m_data) {
+		m_pos.x = 0;
+		m_pos.y = 0;
+	} else {
+		unsigned bytes = lines * m_size.x;
+		char *line = line_pointer(0);
+		for (unsigned i = 0; i < bytes; ++i)
+			*line++ = 0;
+
+		m_first = (m_first + lines) % m_size.y;
+		m_pos.y -= lines;
+	}
+	repaint();
+}
+
+size_t
+console::puts(const char *message)
+{
+	char *line = line_pointer(m_pos.y);
+
+	while (message && *message) {
+		const unsigned x = m_pos.x * m_font.width();
+		const unsigned y = m_pos.y * m_font.height();
+		const char c = *message++;
+
+		switch (c) {
+		case '\t':
+			m_pos.x = (m_pos.x + 4) / 4 * 4;
+			break;
+
+		case '\r':
+			m_pos.x = 0;
+			break;
+
+		case '\n':
+			m_pos.x = 0;
+			m_pos.y++;
+			break;
+
+		default:
+			if (m_data) line[m_pos.x] = c;
+			m_font.draw_glyph(m_screen, c, m_fg, m_bg, x, y);
+			m_pos.x++;
+		}
+
+		if (m_pos.x >= m_size.x) {
+			m_pos.x = m_pos.x % m_size.x;
+			m_pos.y++;
+		}
+
+		if (m_pos.y >= m_size.y) {
+			scroll(1);
+			line = line_pointer(m_pos.y);
+		}
+	}
+}
+

src/modules/main/console.h

@@ -0,0 +1,35 @@
+#pragma once
+
+#include "font.h"
+#include "screen.h"
+#include "util.h"
+
+struct console_data;
+
+class console
+{
+public:
+	console(const font &f, const screen &s, void *scratch, size_t len);
+
+	void repaint();
+	void scroll(unsigned lines);
+
+	size_t puts(const char *message);
+	size_t printf(const char *fmt, ...);
+
+private:
+	char * line_pointer(unsigned line);
+
+	font m_font;
+	screen m_screen;
+
+	coord<unsigned> m_size;
+	coord<unsigned> m_pos;
+	screen::pixel_t m_fg;
+	screen::pixel_t m_bg;
+
+	size_t m_first;
+	size_t m_length;
+
+	char *m_data;
+};

src/modules/main/font.cpp

@@ -55,24 +55,31 @@ font::font(unsigned height, unsigned width, unsigned count, uint8_t const *data)
 	m_data(data)
 {}
 
+font::font(const font &other) :
+	m_size(other.m_size),
+	m_count(other.m_count),
+	m_data(other.m_data)
+{}
+
 void
 font::draw_glyph(
 		screen &s,
 		uint32_t glyph,
-		screen::pixel_t color,
+		screen::pixel_t fg,
+		screen::pixel_t bg,
 		unsigned x,
 		unsigned y) const
 {
-	unsigned bwidth = (m_width+7)/8;
+	unsigned bwidth = (m_size.x+7)/8;
 	uint8_t const *data = m_data + (glyph * glyph_bytes());
 
-	for (int dy = 0; dy < m_height; ++dy) {
+	for (int dy = 0; dy < m_size.y; ++dy) {
 		for (int dx = 0; dx < bwidth; ++dx) {
 			uint8_t byte = data[dy * bwidth + dx];
 			for (int i = 0; i < 8; ++i) {
-				if (dx*8 + i >= m_width) continue;
+				if (dx*8 + i >= m_size.x) continue;
 				const uint8_t mask = 1 << (7-i);
-				uint32_t c = (byte & mask) ? color : 0;
+				uint32_t c = (byte & mask) ? fg : bg;
 				s.draw_pixel(x + dx*8 + i, y + dy, c);
 			}
 		}

src/modules/main/font.h

@@ -2,22 +2,25 @@
 #include <stdint.h>
 
 #include "screen.h"
+#include "util.h"
 
 class font
 {
 public:
 	static font load(void const *data);
+	font(const font &other);
 
-	unsigned glyph_bytes() const { return m_height * ((m_width + 7) / 8); }
+	unsigned glyph_bytes() const { return m_size.y * ((m_size.x + 7) / 8); }
 	unsigned count() const { return m_count; }
-	unsigned width() const { return m_width; }
-	unsigned height() const { return m_height; }
+	unsigned width() const { return m_size.x; }
+	unsigned height() const { return m_size.y; }
 	bool valid() const { return m_count > 0; }
 
 	void draw_glyph(
 			screen &s,
 			uint32_t glyph,
-			screen::pixel_t color,
+			screen::pixel_t fg,
+			screen::pixel_t bg,
 			unsigned x,
 			unsigned y) const;
 
@@ -25,8 +28,7 @@ private:
 	font();
 	font(unsigned height, unsigned width, unsigned count, uint8_t const *data);
 
-	unsigned m_height;
-	unsigned m_width;
+	coord<unsigned> m_size;
 	unsigned m_count;
 	uint8_t const *m_data;
 };

src/modules/main/main.cpp

@@ -1,6 +1,7 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include "console.h"
 #include "font.h"
 #include "kernel_data.h"
 #include "screen.h"
@@ -13,22 +14,25 @@ extern "C" {
 void
 kernel_main(popcorn_data *header)
 {
-	font f = font::load(header->font);
-	screen s{
+	console cons{
+		font::load(header->font),
+		screen{
 			header->frame_buffer,
 			header->hres,
 			header->vres,
 			header->rmask,
 			header->gmask,
-        header->bmask};
+			header->bmask},
+		header->log,
+		header->log_length};
 
-	uint32_t color = header->gmask;
-	uint32_t perline = header->hres / f.width();
-	const char message[] = "Hello, I am text rendered by the kernel! :-D  ";
-	for (int i=0; i<sizeof(message); ++i) {
-        f.draw_glyph(s, message[i], color,
-			(i % perline) * f.width() + 10,
-			(i / perline) * f.height() + 10);
+	const int times = 50;
+	char message[] = " 000  Hello, I am text rendered by the kernel! :-D\n";
+	for (int i = 0; i < times; ++i) {
+		message[1] = '0' + ((i / 100) % 10);
+		message[2] = '0' + ((i / 10) % 10);
+		message[3] = '0' + (i % 10);
+		cons.puts(message);
 	}
 
 	do_the_set_registers(header);

src/modules/main/screen.cpp

@@ -1,11 +1,11 @@
 #include "screen.h"
 
 screen::color_masks::color_masks(pixel_t r, pixel_t g, pixel_t b) : r(r), g(g), b(b) {}
-screen::resolution::resolution(coord_t w, coord_t h) : w(w), h(h) {}
+screen::color_masks::color_masks(const color_masks &o) : r(o.r), g(o.g), b(o.b) {}
 
 screen::screen(
 		void *framebuffer,
-		coord_t hres, coord_t vres, 
+		unsigned hres, unsigned vres,
 		pixel_t rmask, pixel_t gmask, pixel_t bmask) :
 	m_framebuffer(static_cast<pixel_t *>(framebuffer)),
 	m_masks(rmask, gmask, bmask),
@@ -13,6 +13,13 @@ screen::screen(
 {
 }
 
+screen::screen(const screen &other) :
+	m_framebuffer(other.m_framebuffer),
+	m_masks(other.m_masks),
+	m_resolution(other.m_resolution)
+{
+}
+
 void
 screen::fill(pixel_t color)
 {
@@ -22,7 +29,7 @@ screen::fill(pixel_t color)
 }
 
 void
-screen::draw_pixel(coord_t x, coord_t y, pixel_t color)
+screen::draw_pixel(unsigned x, unsigned y, pixel_t color)
 {
-	m_framebuffer[x + y * m_resolution.w] = color;
+	m_framebuffer[x + y * m_resolution.x] = color;
 }

src/modules/main/screen.h

@@ -2,38 +2,37 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include "util.h"
+
 class screen
 {
 public:
-	using coord_t = uint32_t;
 	using pixel_t = uint32_t;
 
 	screen(
 		void *framebuffer,
-		coord_t hres, coord_t vres,
+		unsigned hres, unsigned vres,
 		pixel_t rmask, pixel_t gmask, pixel_t bmask);
 
+	screen(const screen &other);
 
+	unsigned width() const { return m_resolution.x; }
+	unsigned height() const { return m_resolution.y; }
 
 	void fill(pixel_t color);
 	void draw_pixel(unsigned x, unsigned y, pixel_t color);
 
+	screen() = delete;
+
 	struct color_masks {
 		pixel_t r, g, b;
 		color_masks(pixel_t r, pixel_t g, pixel_t b);
-    };
-	screen() = delete;
-	screen(const screen &) = delete;
-
-    struct resolution {
-        coord_t w, h;
-        resolution(coord_t w, coord_t h);
-        coord_t size() const { return w * h; }
+		color_masks(const color_masks &other);
 	};
 
 private:
 	pixel_t *m_framebuffer;
 	color_masks m_masks;
-    resolution m_resolution;
+	coord<unsigned> m_resolution;
 };
 

src/modules/main/util.h

@@ -0,0 +1,9 @@
+#pragma once
+
+template <typename T>
+struct coord {
+	T x, y;
+	coord() : x(T{}), y(T{}) {}
+	coord(T x, T y) : x(x), y(y) {}
+	T size() const { return x * y; }
+};