Console-writing code for the new x86 setup code
H. Peter Anvin [Wed, 11 Jul 2007 19:18:45 +0000 (12:18 -0700)]
This implements writing text to the console, including printf().

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/i386/boot/printf.c [new file with mode: 0644]
arch/i386/boot/tty.c [new file with mode: 0644]

diff --git a/arch/i386/boot/printf.c b/arch/i386/boot/printf.c
new file mode 100644 (file)
index 0000000..1a09f93
--- /dev/null
@@ -0,0 +1,307 @@
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ *   Copyright (C) 1991, 1992 Linus Torvalds
+ *   Copyright 2007 rPath, Inc. - All Rights Reserved
+ *
+ *   This file is part of the Linux kernel, and is made available under
+ *   the terms of the GNU General Public License version 2.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * arch/i386/boot/printf.c
+ *
+ * Oh, it's a waste of space, but oh-so-yummy for debugging.  This
+ * version of printf() does not include 64-bit support.  "Live with
+ * it."
+ *
+ */
+
+#include "boot.h"
+
+static int skip_atoi(const char **s)
+{
+       int i = 0;
+
+       while (isdigit(**s))
+               i = i * 10 + *((*s)++) - '0';
+       return i;
+}
+
+#define ZEROPAD        1               /* pad with zero */
+#define SIGN   2               /* unsigned/signed long */
+#define PLUS   4               /* show plus */
+#define SPACE  8               /* space if plus */
+#define LEFT   16              /* left justified */
+#define SPECIAL        32              /* 0x */
+#define LARGE  64              /* use 'ABCDEF' instead of 'abcdef' */
+
+#define do_div(n,base) ({ \
+int __res; \
+__res = ((unsigned long) n) % (unsigned) base; \
+n = ((unsigned long) n) / (unsigned) base; \
+__res; })
+
+static char *number(char *str, long num, int base, int size, int precision,
+                   int type)
+{
+       char c, sign, tmp[66];
+       const char *digits = "0123456789abcdefghijklmnopqrstuvwxyz";
+       int i;
+
+       if (type & LARGE)
+               digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+       if (type & LEFT)
+               type &= ~ZEROPAD;
+       if (base < 2 || base > 36)
+               return 0;
+       c = (type & ZEROPAD) ? '0' : ' ';
+       sign = 0;
+       if (type & SIGN) {
+               if (num < 0) {
+                       sign = '-';
+                       num = -num;
+                       size--;
+               } else if (type & PLUS) {
+                       sign = '+';
+                       size--;
+               } else if (type & SPACE) {
+                       sign = ' ';
+                       size--;
+               }
+       }
+       if (type & SPECIAL) {
+               if (base == 16)
+                       size -= 2;
+               else if (base == 8)
+                       size--;
+       }
+       i = 0;
+       if (num == 0)
+               tmp[i++] = '0';
+       else
+               while (num != 0)
+                       tmp[i++] = digits[do_div(num, base)];
+       if (i > precision)
+               precision = i;
+       size -= precision;
+       if (!(type & (ZEROPAD + LEFT)))
+               while (size-- > 0)
+                       *str++ = ' ';
+       if (sign)
+               *str++ = sign;
+       if (type & SPECIAL) {
+               if (base == 8)
+                       *str++ = '0';
+               else if (base == 16) {
+                       *str++ = '0';
+                       *str++ = digits[33];
+               }
+       }
+       if (!(type & LEFT))
+               while (size-- > 0)
+                       *str++ = c;
+       while (i < precision--)
+               *str++ = '0';
+       while (i-- > 0)
+               *str++ = tmp[i];
+       while (size-- > 0)
+               *str++ = ' ';
+       return str;
+}
+
+int vsprintf(char *buf, const char *fmt, va_list args)
+{
+       int len;
+       unsigned long num;
+       int i, base;
+       char *str;
+       const char *s;
+
+       int flags;              /* flags to number() */
+
+       int field_width;        /* width of output field */
+       int precision;          /* min. # of digits for integers; max
+                                  number of chars for from string */
+       int qualifier;          /* 'h', 'l', or 'L' for integer fields */
+
+       for (str = buf; *fmt; ++fmt) {
+               if (*fmt != '%') {
+                       *str++ = *fmt;
+                       continue;
+               }
+
+               /* process flags */
+               flags = 0;
+             repeat:
+               ++fmt;          /* this also skips first '%' */
+               switch (*fmt) {
+               case '-':
+                       flags |= LEFT;
+                       goto repeat;
+               case '+':
+                       flags |= PLUS;
+                       goto repeat;
+               case ' ':
+                       flags |= SPACE;
+                       goto repeat;
+               case '#':
+                       flags |= SPECIAL;
+                       goto repeat;
+               case '0':
+                       flags |= ZEROPAD;
+                       goto repeat;
+               }
+
+               /* get field width */
+               field_width = -1;
+               if (isdigit(*fmt))
+                       field_width = skip_atoi(&fmt);
+               else if (*fmt == '*') {
+                       ++fmt;
+                       /* it's the next argument */
+                       field_width = va_arg(args, int);
+                       if (field_width < 0) {
+                               field_width = -field_width;
+                               flags |= LEFT;
+                       }
+               }
+
+               /* get the precision */
+               precision = -1;
+               if (*fmt == '.') {
+                       ++fmt;
+                       if (isdigit(*fmt))
+                               precision = skip_atoi(&fmt);
+                       else if (*fmt == '*') {
+                               ++fmt;
+                               /* it's the next argument */
+                               precision = va_arg(args, int);
+                       }
+                       if (precision < 0)
+                               precision = 0;
+               }
+
+               /* get the conversion qualifier */
+               qualifier = -1;
+               if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L') {
+                       qualifier = *fmt;
+                       ++fmt;
+               }
+
+               /* default base */
+               base = 10;
+
+               switch (*fmt) {
+               case 'c':
+                       if (!(flags & LEFT))
+                               while (--field_width > 0)
+                                       *str++ = ' ';
+                       *str++ = (unsigned char)va_arg(args, int);
+                       while (--field_width > 0)
+                               *str++ = ' ';
+                       continue;
+
+               case 's':
+                       s = va_arg(args, char *);
+                       len = strnlen(s, precision);
+
+                       if (!(flags & LEFT))
+                               while (len < field_width--)
+                                       *str++ = ' ';
+                       for (i = 0; i < len; ++i)
+                               *str++ = *s++;
+                       while (len < field_width--)
+                               *str++ = ' ';
+                       continue;
+
+               case 'p':
+                       if (field_width == -1) {
+                               field_width = 2 * sizeof(void *);
+                               flags |= ZEROPAD;
+                       }
+                       str = number(str,
+                                    (unsigned long)va_arg(args, void *), 16,
+                                    field_width, precision, flags);
+                       continue;
+
+               case 'n':
+                       if (qualifier == 'l') {
+                               long *ip = va_arg(args, long *);
+                               *ip = (str - buf);
+                       } else {
+                               int *ip = va_arg(args, int *);
+                               *ip = (str - buf);
+                       }
+                       continue;
+
+               case '%':
+                       *str++ = '%';
+                       continue;
+
+                       /* integer number formats - set up the flags and "break" */
+               case 'o':
+                       base = 8;
+                       break;
+
+               case 'X':
+                       flags |= LARGE;
+               case 'x':
+                       base = 16;
+                       break;
+
+               case 'd':
+               case 'i':
+                       flags |= SIGN;
+               case 'u':
+                       break;
+
+               default:
+                       *str++ = '%';
+                       if (*fmt)
+                               *str++ = *fmt;
+                       else
+                               --fmt;
+                       continue;
+               }
+               if (qualifier == 'l')
+                       num = va_arg(args, unsigned long);
+               else if (qualifier == 'h') {
+                       num = (unsigned short)va_arg(args, int);
+                       if (flags & SIGN)
+                               num = (short)num;
+               } else if (flags & SIGN)
+                       num = va_arg(args, int);
+               else
+                       num = va_arg(args, unsigned int);
+               str = number(str, num, base, field_width, precision, flags);
+       }
+       *str = '\0';
+       return str - buf;
+}
+
+int sprintf(char *buf, const char *fmt, ...)
+{
+       va_list args;
+       int i;
+
+       va_start(args, fmt);
+       i = vsprintf(buf, fmt, args);
+       va_end(args);
+       return i;
+}
+
+int printf(const char *fmt, ...)
+{
+       char printf_buf[1024];
+       va_list args;
+       int printed;
+
+       va_start(args, fmt);
+       printed = vsprintf(printf_buf, fmt, args);
+       va_end(args);
+
+       puts(printf_buf);
+
+       return printed;
+}
diff --git a/arch/i386/boot/tty.c b/arch/i386/boot/tty.c
new file mode 100644 (file)
index 0000000..a8db787
--- /dev/null
@@ -0,0 +1,112 @@
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ *   Copyright (C) 1991, 1992 Linus Torvalds
+ *   Copyright 2007 rPath, Inc. - All Rights Reserved
+ *
+ *   This file is part of the Linux kernel, and is made available under
+ *   the terms of the GNU General Public License version 2.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * arch/i386/boot/tty.c
+ *
+ * Very simple screen I/O
+ * XXX: Probably should add very simple serial I/O?
+ */
+
+#include "boot.h"
+
+/*
+ * These functions are in .inittext so they can be used to signal
+ * error during initialization.
+ */
+
+void __attribute__((section(".inittext"))) putchar(int ch)
+{
+       unsigned char c = ch;
+
+       if (c == '\n')
+               putchar('\r');  /* \n -> \r\n */
+
+       /* int $0x10 is known to have bugs involving touching registers
+          it shouldn't.  Be extra conservative... */
+       asm volatile("pushal; int $0x10; popal"
+                    : : "b" (0x0007), "c" (0x0001), "a" (0x0e00|ch));
+}
+
+void __attribute__((section(".inittext"))) puts(const char *str)
+{
+       int n = 0;
+       while (*str) {
+               putchar(*str++);
+               n++;
+       }
+}
+
+/*
+ * Read the CMOS clock through the BIOS, and return the
+ * seconds in BCD.
+ */
+
+static u8 gettime(void)
+{
+       u16 ax = 0x0200;
+       u16 cx, dx;
+
+       asm("int $0x1a"
+           : "+a" (ax), "=c" (cx), "=d" (dx)
+           : : "ebx", "esi", "edi");
+
+       return dx >> 8;
+}
+
+/*
+ * Read from the keyboard
+ */
+int getchar(void)
+{
+       u16 ax = 0;
+       asm("int $0x16" : "+a" (ax));
+
+       return ax & 0xff;
+}
+
+static int kbd_pending(void)
+{
+       u8 pending;
+       asm("int $0x16; setnz %0"
+           : "=rm" (pending)
+           : "a" (0x0100));
+       return pending;
+}
+
+void kbd_flush(void)
+{
+       for (;;) {
+               if (!kbd_pending())
+                       break;
+               getchar();
+       }
+}
+
+int getchar_timeout(void)
+{
+       int cnt = 30;
+       int t0, t1;
+
+       t0 = gettime();
+
+       while (cnt) {
+               if (kbd_pending())
+                       return getchar();
+
+               t1 = gettime();
+               if (t0 != t1) {
+                       cnt--;
+                       t0 = t1;
+               }
+       }
+
+       return 0;               /* Timeout! */
+}