Console-writing code for the new x86 setup code

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>

2 files changed, 419 insertions, 0 deletions

diff --git a/arch/i386/boot/printf.c b/arch/i386/boot/printf.c
new file mode 100644
index 000000000000..1a09f9309d3c
--- /dev/null
+++ b/arch/i386/boot/printf.c
@@ -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
index 000000000000..a8db78736b02
--- /dev/null
+++ b/arch/i386/boot/tty.c
@@ -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! */
+}