feature: multiple screens + cursor move (bug to fix)

style: reorganise code structure

src/terminal/put.c

@@ -0,0 +1,130 @@
+#include "ctype.h"
+#include "kprintf.h"
+#include "string.h"
+#include "sys/io.h"
+#include "terminal.h"
+
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+
+static struct screen screens[TERM_COUNT];
+struct screen *screen = &screens[0];
+
+static inline uint8_t vga_entry_color(enum vga_color fg, enum vga_color bg)
+{
+	return fg | bg << 4;
+}
+
+static inline uint16_t vga_entry(unsigned char uc, uint8_t color)
+{
+	return (uint16_t)uc | (uint16_t)color << 8;
+}
+
+void terminal_initialize(void)
+{
+	for (size_t y = 0; y < VGA_HEIGHT; y++) {
+		for (size_t x = 0; x < VGA_WIDTH; x++) {
+			const size_t index = y * VGA_WIDTH + x;
+			TERM_BUF[index] = vga_entry(' ', screen->color);
+		}
+	}
+	for (int i = 0; i < TERM_COUNT; i++) {
+		screens[i].row = 0;
+		screens[i].column = 0;
+		screens[i].color =
+		    vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK);
+		memcpy(screens[i].buffer, TERM_BUF, sizeof(screen->buffer));
+	}
+}
+
+void terminal_set_screen(int pos)
+{
+	memcpy(screen->buffer, TERM_BUF, sizeof(screen->buffer));
+	screen = &screens[pos];
+	memcpy(TERM_BUF, screen->buffer, sizeof(screen->buffer));
+}
+
+void terminal_setcolor(uint8_t color)
+{
+	screen->color = color;
+}
+
+void terminal_putentryat(char c, uint8_t color, size_t x, size_t y)
+{
+	const size_t index = y * VGA_WIDTH + x;
+	TERM_BUF[index] = vga_entry(c, color);
+}
+
+static void terminal_scroll(void)
+{
+	screen->row--;
+	for (size_t i = 0; i < VGA_WIDTH * (VGA_HEIGHT - 1); i++)
+		TERM_BUF[i] = TERM_BUF[i + VGA_WIDTH];
+	for (size_t i = 0; i < VGA_WIDTH; i++)
+		terminal_putentryat(' ', screen->color, i, VGA_HEIGHT - 1);
+}
+
+static void terminal_new_line(void)
+{
+	screen->column = 0;
+	if (++screen->row == VGA_HEIGHT)
+		terminal_scroll();
+}
+
+int terminal_putchar(char c)
+{
+	if (c == '\r')
+		screen->column = 0;
+	else if (c == '\n')
+		terminal_new_line();
+	if (!isprint(c))
+		return 1;
+	terminal_putentryat(c, screen->color, screen->column, screen->row);
+	if (++screen->column == VGA_WIDTH)
+		terminal_new_line();
+	return 1;
+}
+
+int terminal_write(const char *data, size_t size)
+{
+	size_t i;
+	for (i = 0; i < size; i++)
+		terminal_putchar(data[i]);
+	return (int)i;
+}
+
+int terminal_writestring(const char *data)
+{
+	size_t len = strlen(data);
+	terminal_write(data, len);
+	return len;
+}
+
+int terminal_writelong(long n)
+{
+	long div = 10;
+	int rv = 0;
+	if (n < 0) {
+		rv += terminal_putchar('-');
+		n *= -1;
+	}
+	div = 1;
+	while (div <= n / 10)
+		div *= 10;
+	while (div > 0) {
+		rv += terminal_putchar('0' + n / div % 10);
+		div /= 10;
+	}
+	return rv;
+}
+
+void update_cursor(void)
+{
+	uint16_t pos = screen->row * VGA_WIDTH + screen->column;
+
+	outb(0x3D4, 0x0F);
+	outb(0x3D5, pos & 0xFF);
+	outb(0x3D4, 0x0E);
+	outb(0x3D5, (pos >> 8) & 0xFF);
+}