+/** @file console.c
+ * @brief A console driver.
+ *
+ * @author Joshua Wise (jwise) <joshua@joshuawise.com>
+ * @bug None known
+ */
+
+#include <console.h>
+#include "console-ext.h"
+#include <io.h>
+
+#define POS_IS_VALID(row, col) ((row) >= 0 && (row) < CONSOLE_HEIGHT && (col) >= 0 && (col) < CONSOLE_WIDTH)
+
+/** @brief A structure describing a console that is backed by memory.
+ *
+ * In the mode of designing for extensibility, all of the console driver's
+ * state is encapsulated in a 'struct console', which would ostensibly make
+ * it easier to create virtual consoles later. All of the console driver's
+ * workings touch this struct; ideally, there are no references to
+ * CONSOLE_MEM_BASE or other hardware outside of this. In practice, this
+ * isn't quite the case (see update_cursor()).... but we're close.
+ */
+struct console {
+ int row; /**< The current row. */
+ int col; /**< The current column. */
+ unsigned char attr; /**< The current color/attribute. */
+ unsigned char *base; /**< The current base to write data to.
+ * Might not be equal to physbase if we're
+ * in a different virtual console right
+ * now or we have requested a backbuffer!
+ */
+ unsigned char *physbase; /**< The physical memory base for
+ * this console.
+ */
+ int showcursor; /**< Whether the cursor should be shown
+ * by update_cursor().
+ */
+ int initialized; /**< Whether the console has been
+ * initialized. Functions should check
+ * this and call clear_console() before
+ * running if this is zero.
+ */
+ int backbuffer; /**< Whether we're currently writing to a
+ * backbuffer instead of the physical
+ * video memory.
+ */
+};
+
+/** @brief The structure describing the one console on the system. Should
+ * not be touched by anyone but the initializer for curcons!
+ */
+static struct console cons = {
+ .row = 0,
+ .col = 0,
+ .attr = FGND_LGRAY,
+ .base = (unsigned char *)CONSOLE_MEM_BASE,
+ .physbase = (unsigned char *)CONSOLE_MEM_BASE,
+ .showcursor = 1,
+ .initialized = 0,
+ .backbuffer = 0,
+};
+
+/** @brief The current console that all console.c operations work on. */
+static struct console *curcons = &cons;
+
+/** @brief Makes sure that the VGA cursor matches with the console.c's idea
+ * of where the cursor should be.
+ *
+ * update_cursor would be trivial, but for a few important checks. In
+ * particular, it won't touch the cursor at all if we're backbuffered
+ * (since that would make the cursor fly around a screen that isn't
+ * actually being updated), and if the cursor is hidden, it sets it to an
+ * out-of-bounds segment to make sure that it's actually hidden.
+ */
+static void update_cursor()
+{
+ if (curcons->backbuffer)
+ return;
+ if (curcons->showcursor)
+ {
+ unsigned short addr = (curcons->row * CONSOLE_WIDTH + curcons->col);
+ outb(CRTC_IDX_REG, CRTC_CURSOR_MSB_IDX);
+ outb(CRTC_DATA_REG, (addr >> 8));
+ outb(CRTC_IDX_REG, CRTC_CURSOR_LSB_IDX);
+ outb(CRTC_DATA_REG, addr & 0xFF);
+ } else {
+ outb(CRTC_IDX_REG, CRTC_CURSOR_MSB_IDX);
+ outb(CRTC_DATA_REG, 255 /* invalid */);
+ outb(CRTC_IDX_REG, CRTC_CURSOR_LSB_IDX);
+ outb(CRTC_DATA_REG, 255 /* invalid */);
+ }
+}
+
+/** @brief Redirects console writes to a backbuffer.
+ *
+ * Verifies that the console is not already backbuffered. If it's not, it
+ * allocates a backbuffer, copies the current console into the backbuffer,
+ * and sets the backbuffered flag.
+ *
+ * This isn't just theoretical, by the way. The game screen's timer causes
+ * it to repaint every frame (for lack of a better way to do it), which is
+ * fine in qemu (which is fast), but causes severe flicker in simics. This
+ * backbuffering logic seems to have alleviated the flicker.
+ *
+ * @see cons_debackbuffer
+ */
+/*void cons_backbuffer()
+{
+ if (!curcons->initialized)
+ clear_console();
+ if (curcons->backbuffer)
+ return;
+ curcons->base = malloc(CONSOLE_WIDTH * CONSOLE_HEIGHT * 2);
+ memcpy(curcons->base, curcons->physbase, CONSOLE_WIDTH * CONSOLE_HEIGHT * 2);
+ curcons->backbuffer = 1;
+}*/
+
+/** @brief Turns off the backbuffer.
+ *
+ * Verifies that we are currently backbuffered. If so, copies the
+ * backbuffer into video memory, frees the backbuffer, sets the pointer
+ * back to video memory, clears the backbuffered flag, and updates the
+ * hardware cursor.
+ *
+ * @see cons_backbuffer
+ */
+/*void cons_debackbuffer()
+{
+ if (!curcons->initialized)
+ clear_console();
+ if (!curcons->backbuffer)
+ return;
+ memcpy(curcons->physbase, curcons->base, CONSOLE_WIDTH * CONSOLE_HEIGHT * 2);
+ free(curcons->base);
+ curcons->base = curcons->physbase;
+ curcons->backbuffer = 0;
+ update_cursor();
+}*/
+
+int putbyte(char ch)
+{
+ if (!curcons->initialized)
+ clear_console();
+
+ /* Make sure to handle special cases nicely.*/
+ switch(ch)
+ {
+ case '\n':
+ curcons->row++;
+ if (curcons->row >= CONSOLE_HEIGHT) /* Moving off the end? Scroll. */
+ {
+ int c;
+ memmove(curcons->base, curcons->base + 2*CONSOLE_WIDTH, 2*CONSOLE_WIDTH*(CONSOLE_HEIGHT-1));
+ curcons->row--;
+ for (c=0; c<CONSOLE_WIDTH; c++) /* Clear the newly blank bottom line. */
+ {
+ curcons->base[(curcons->row * CONSOLE_WIDTH + c) * 2] = ' ';
+ curcons->base[(curcons->row * CONSOLE_WIDTH + c) * 2 + 1] = curcons->attr;
+ }
+ }
+ // fall through
+ case '\r':
+ curcons->col = 0;
+ update_cursor();
+ break;
+ case '\b':
+ if (curcons->col)
+ {
+ curcons->col--;
+ curcons->base[(curcons->row*CONSOLE_WIDTH + curcons->col) * 2] = ' ';
+ }
+ update_cursor();
+ break;
+ default:
+ curcons->base[(curcons->row*CONSOLE_WIDTH + curcons->col) * 2] = ch;
+ curcons->base[(curcons->row*CONSOLE_WIDTH + curcons->col) * 2 + 1] = curcons->attr;
+ curcons->col++;
+ if (curcons->col >= CONSOLE_WIDTH)
+ putbyte('\n');
+ update_cursor();
+ }
+ return ch;
+}
+
+void putbytes(const char *s, int len)
+{
+ if (!curcons->initialized)
+ clear_console();
+
+ while (len--)
+ putbyte(*(s++));
+}
+
+int set_term_color(int color)
+{
+ if (!curcons->initialized)
+ clear_console();
+
+ curcons->attr = (unsigned char)color;
+ return 0;
+}
+
+void get_term_color(int *color)
+{
+ if (!curcons->initialized)
+ clear_console();
+
+ *color = (int)curcons->attr;
+}
+
+int set_cursor(int row, int col)
+{
+ if (!curcons->initialized)
+ clear_console();
+ if (!POS_IS_VALID(row, col))
+ return -1;
+ curcons->row = row;
+ curcons->col = col;
+ update_cursor();
+ return 0;
+}
+
+void get_cursor(int *row, int *col)
+{
+ if (!curcons->initialized)
+ clear_console();
+ *row = curcons->row;
+ *col = curcons->col;
+}
+
+void hide_cursor()
+{
+ if (!curcons->initialized)
+ clear_console();
+ curcons->showcursor = 0;
+ update_cursor();
+}
+
+void show_cursor()
+{
+ if (!curcons->initialized)
+ clear_console();
+ curcons->showcursor = 1;
+ update_cursor();
+}
+
+void clear_console()
+{
+ int i;
+ curcons->initialized = 1;
+ curcons->row = 0;
+ curcons->col = 0;
+ for (i = 0; i < CONSOLE_WIDTH * CONSOLE_HEIGHT; i++)
+ {
+ curcons->base[i*2] = ' ';
+ curcons->base[i*2+1] = FGND_LGRAY;
+ }
+ update_cursor();
+}
+
+void draw_char(int row, int col, int ch, int color)
+{
+ if (!POS_IS_VALID(row, col))
+ return;
+ curcons->base[2 * (CONSOLE_WIDTH * row + col)] = (unsigned char)ch;
+ curcons->base[2 * (CONSOLE_WIDTH * row + col)+1] = (unsigned char)color;
+}
+
+char get_char(int row, int col)
+{
+ if (!POS_IS_VALID(row, col))
+ return 0;
+ return curcons->base[2 * (CONSOLE_WIDTH * row + col)];
+}
git.joshuawise.com / netwatch.git / commitdiff