#include "io.h"
#include "timer.h"
-static void
-set_serial (int bps, int bits, enum parity_type parity, int stop)
-{
- int baud_base = 1843200 / 16; /* Base rate of 16550A. */
- uint16_t divisor = baud_base / bps; /* Clock rate divisor. */
-
- /* Enable DLAB. */
- outb (LCR_REG, make_lcr (bits, parity, stop, false, true));
-
- /* Set baud rate. */
- outb (LS_REG, divisor & 0xff);
- outb (MS_REG, divisor >> 8);
-
- /* Reset DLAB. */
- outb (LCR_REG, make_lcr (bits, parity, stop, false, false));
-}
+static void set_serial (int bps, int bits, enum parity_type parity, int stop);
+/* Initializes the serial port device. */
void
serial_init (void)
{
outb (MCR_REG, 0); /* Turn off output lines. */
}
+/* Sends BYTE to the serial port. */
void
serial_outb (uint8_t byte)
{
continue;
outb (THR_REG, byte);
}
+
+/* Configures the first serial port for BPS bits per second,
+ BITS bits per byte, the given PARITY, and STOP stop bits. */
+static void
+set_serial (int bps, int bits, enum parity_type parity, int stop)
+{
+ int baud_base = 1843200 / 16; /* Base rate of 16550A. */
+ uint16_t divisor = baud_base / bps; /* Clock rate divisor. */
+
+ /* Enable DLAB. */
+ outb (LCR_REG, make_lcr (bits, parity, stop, false, true));
+
+ /* Set baud rate. */
+ outb (LS_REG, divisor & 0xff);
+ outb (MS_REG, divisor >> 8);
+
+ /* Reset DLAB. */
+ outb (LCR_REG, make_lcr (bits, parity, stop, false, false));
+}
#error 8254 timer requires TIMER_FREQ >= 19
#endif
+/* Number of timer ticks since OS booted. */
static volatile int64_t ticks;
-static void
-irq20_timer (struct intr_frame *args UNUSED)
-{
- ticks++;
- intr_yield_on_return ();
-}
+static intr_handler_func timer_interrupt;
/* Sets up the 8254 Programmable Interrupt Timer (PIT) to
interrupt PIT_FREQ times per second, and registers the
outb (0x40, count & 0xff);
outb (0x40, count >> 8);
- intr_register (0x20, 0, INTR_OFF, irq20_timer, "8254 Timer");
+ intr_register (0x20, 0, INTR_OFF, timer_interrupt, "8254 Timer");
}
+/* Returns the number of timer ticks since the OS booted. */
int64_t
timer_ticks (void)
{
return t;
}
+/* Returns the number of timer ticks elapsed since THEN, which
+ should be a value once returned by timer_ticks(). */
int64_t
timer_elapsed (int64_t then)
{
return timer_ticks () - then;
}
-/* Suspends execution for approximately DURATION milliseconds. */
+/* Suspends execution for approximately MS milliseconds. */
void
timer_msleep (int64_t ms)
{
continue;
}
+/* Suspends execution for approximately US microseconds.
+ Note: this is ridiculously inaccurate. */
void
timer_usleep (int64_t us)
{
timer_msleep (us / 1000 + 1);
}
+/* Suspends execution for approximately NS nanoseconds.
+ Note: this is ridiculously inaccurate. */
void
timer_nsleep (int64_t ns)
{
timer_msleep (ns / 1000000 + 1);
}
+\f
+/* Timer interrupt handler. */
+static void
+timer_interrupt (struct intr_frame *args UNUSED)
+{
+ ticks++;
+ intr_yield_on_return ();
+}
#include "lib.h"
#include "mmu.h"
-static size_t vga_cols, vga_rows;
-static size_t vga_x, vga_y;
-static uint16_t *vga_base;
+/* VGA text screen support. See [FREEVGA] for more information. */
-void
-vga_init (void)
-{
- vga_cols = 80;
- vga_rows = 25;
- vga_base = (uint16_t *) ptov (0xb8000);
- vga_cls ();
-}
+/* Number of columns and rows on the text display. */
+#define COL_CNT 80
+#define ROW_CNT 25
-void
-vga_cls (void)
-{
- size_t i;
- for (i = 0; i < vga_cols * vga_rows; i++)
- vga_base[i] = 0x0700;
- vga_x = vga_y = 0;
-}
+/* Current cursor position. (0,0) is in the upper left corner of
+ the display. */
+static size_t cx, cy;
-static void
-vga_newline (void)
-{
- vga_x = 0;
- vga_y++;
- if (vga_y >= vga_rows)
- {
- vga_y = vga_rows - 1;
- memmove (vga_base, vga_base + vga_cols,
- vga_cols * (vga_rows - 1) * 2);
- memset (vga_base + vga_cols * (vga_rows - 1),
- 0, vga_cols * 2);
- }
-}
+/* Attribute value for gray text on a black background. */
+#define GRAY_ON_BLACK 0x07
-static void
-move_cursor (void)
+/* Framebuffer. See [FREEVGA] under "VGA Text Mode Operation".
+ The character at (x,y) is fb[y][x][0].
+ The attribute at (x,y) is fb[y][x][1]. */
+static uint8_t (*fb)[COL_CNT][2];
+
+static void clear_row (size_t y);
+static void cls (void);
+static void newline (void);
+static void move_cursor (void);
+
+/* Initializes the VGA text display and clears the screen. */
+void
+vga_init (void)
{
- uint16_t cp = (vga_x + vga_cols * vga_y);
- outw (0x3d4, 0x0e | (cp & 0xff00));
- outw (0x3d4, 0x0f | (cp << 8));
+ fb = ptov (0xb8000);
+ cls ();
}
+/* Writes C to the VGA text display, interpreting control
+ characters in the conventional ways. */
void
vga_putc (int c)
{
switch (c)
{
case '\n':
- vga_newline ();
+ newline ();
break;
case '\f':
- vga_cls ();
+ cls ();
break;
case '\b':
- if (vga_x > 0)
- vga_x--;
+ if (cx > 0)
+ cx--;
break;
case '\r':
- vga_x = 0;
+ cx = 0;
break;
case '\t':
- vga_x = (vga_x + 8) / 8 * 8;
- if (vga_x >= vga_cols)
- vga_newline ();
+ cx = ROUND_UP (cx + 1, 8);
+ if (cx >= COL_CNT)
+ newline ();
break;
default:
- vga_base[vga_x + vga_y * vga_cols] = 0x0700 | c;
- vga_x++;
- if (vga_x >= vga_cols)
- vga_newline ();
+ fb[cy][cx][0] = c;
+ fb[cy][cx][1] = GRAY_ON_BLACK;
+ if (++cx >= COL_CNT)
+ newline ();
break;
}
+ /* Update cursor position. */
move_cursor ();
}
+\f
+/* Clears the screen and moves the cursor to the upper left. */
+static void
+cls (void)
+{
+ size_t y;
+
+ for (y = 0; y < ROW_CNT; y++)
+ clear_row (y);
+
+ cx = cy = 0;
+ move_cursor ();
+}
+
+/* Clears row Y to spaces. */
+static void
+clear_row (size_t y)
+{
+ size_t x;
+
+ for (x = 0; x < COL_CNT; x++)
+ {
+ fb[y][x][0] = ' ';
+ fb[y][x][1] = GRAY_ON_BLACK;
+ }
+}
+
+/* Advances the cursor to the first column in the next line on
+ the screen. If the cursor is already on the last line on the
+ screen, scrolls the screen upward one line. */
+static void
+newline (void)
+{
+ cx = 0;
+ cy++;
+ if (cy >= ROW_CNT)
+ {
+ cy = ROW_CNT - 1;
+ memmove (&fb[0], &fb[1], sizeof fb[0] * (ROW_CNT - 1));
+ clear_row (ROW_CNT - 1);
+ }
+}
+
+/* Moves the hardware cursor to (cx,cy). */
+static void
+move_cursor (void)
+{
+ /* See [FREEVGA] under "Manipulating the Text-mode Cursor". */
+ uint16_t cp = cx + COL_CNT * cy;
+ outw (0x3d4, 0x0e | (cp & 0xff00));
+ outw (0x3d4, 0x0f | (cp << 8));
+}
+
#define HEADER_VGA_H 1
void vga_init (void);
-void vga_cls (void);
void vga_putc (int);
#endif /* vga.h */
projects / pintos-anon / commitdiff