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#include "kprint.h"
#include "serial.h"
#include <kc/lib.h>
#include <stdint.h>
__attribute__((optimize("O3")))
int kputchar(int c)
{
return serial_putchar(c);
}
__attribute__((optimize("O3")))
int kputs(const char *s)
{
while (*s)
{
kputchar(*s++);
}
return 0;
}
static char *convert_scalar(
uint64_t value,
unsigned base,
char *buffer,
size_t bufsz)
{
static const char *stringdigits = "0123456789abcdef";
// the string will be built from the lower-to-higher value, and the
// result pointer will point to the first character of the string in
// the supplied buffer
// gotta zero the buffer
memset(buffer, 0, bufsz);
// the string is being built backwards, so the pointer needs to be
// at the last byte of the string
char *result = buffer + bufsz - 1;
// result >= buffer condition ensures we don't overflow
while (value > 0 && result >= buffer)
{
*--result = stringdigits[value % base];
value /= base;
}
return result;
}
static inline int print_scalar(uint64_t value, int base)
{
char buffer[65];
char *s = convert_scalar(
value,
base,
buffer,
sizeof(buffer));
kputs(s);
return strlen(s);
}
int kvprintf(const char *restrict format, va_list arguments)
{
int count = 0;
while (*format)
{
if (*format != '%')
{
kputchar(*format++);
count++;
continue;
}
switch (*++format)
{
case 0:
return count;
case '%':
count++;
kputchar('%');
break;
case 's':
{
const char *s = va_arg(arguments, const char *);
count += strlen(s);
kputs(s);
break;
}
case 'x':
print_scalar(va_arg(arguments, uint64_t), 16);
break;
case 'd':
print_scalar(va_arg(arguments, uint64_t), 10);
break;
case 'o':
print_scalar(va_arg(arguments, uint64_t), 8);
break;
case 'b':
print_scalar(va_arg(arguments, uint64_t), 2);
break;
default:
break;
}
format++;
}
va_end(arguments);
return count;
}
int kprintf(const char *restrict format, ...)
{
va_list arguments;
va_start (arguments, format);
return kvprintf(format, arguments);
}
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