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Subject[x86 setup 20/33] Console-writing code for the new x86 setup code
Date
From: H. Peter Anvin <hpa@zytor.com>

This implements writing text to the console, including printf().

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
arch/i386/boot/printf.c | 307 +++++++++++++++++++++++++++++++++++++++++++++++
arch/i386/boot/tty.c | 112 +++++++++++++++++
2 files changed, 419 insertions(+), 0 deletions(-)
create mode 100644 arch/i386/boot/printf.c
create mode 100644 arch/i386/boot/tty.c
diff --git a/arch/i386/boot/printf.c b/arch/i386/boot/printf.c
new file mode 100644
index 0000000..1a09f93
--- /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 0000000..a8db787
--- /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! */
+}
--
1.5.2.2
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