toaruos/kprintf.c
2011-01-17 10:24:55 -06:00

106 lines
1.9 KiB
C

#include <system.h>
#define args_list char *
#define _arg_stack_size(type) (((sizeof(type)-1)/sizeof(int)+1)*sizeof(int))
#define args_start(ap, fmt) do { \
ap = (char *)((unsigned int)&fmt + _arg_stack_size(&fmt));\
} while (0)
#define args_end(ap)
#define args_next(ap, type) (((type *)(ap+=_arg_stack_size(type)))[-1])
static char buf[1024] = {-1};
static int ptr = -1;
/*
* Parse integer
*/
static void
parse_num(
unsigned int value,
unsigned int base
) {
unsigned int n = value / base;
int r = value % base;
if (r < 0) {
r += base;
--n;
}
if (value >= base) {
parse_num(n, base);
}
buf[ptr++] = (r+'0');
}
/*
* Parse hexadecimal
*/
static void
parse_hex(
unsigned int value
) {
int i = 8;
while (i-- > 0) {
buf[ptr++] = "0123456789abcdef"[(value>>(i*4))&0xF];
}
}
/*
* kprintf
* %s, %c, %x, %d, %%
* (Kernel) Print a formatted string.
*/
void
kprintf(
const char *fmt,
...
) {
int i = 0;
char *s;
args_list args;
args_start(args, fmt);
ptr = 0;
for ( ; fmt[i]; ++i) {
if ((fmt[i] != '%') && (fmt[i] != '\\')) {
buf[ptr++] = fmt[i];
continue;
} else if (fmt[i] == '\\') {
switch (fmt[++i]) {
case 'a': buf[ptr++] = '\a'; break;
case 'b': buf[ptr++] = '\b'; break;
case 't': buf[ptr++] = '\t'; break;
case 'n': buf[ptr++] = '\n'; break;
case 'r': buf[ptr++] = '\r'; break;
case '\\':buf[ptr++] = '\\'; break;
}
continue;
}
/* fmt[i] == '%' */
switch (fmt[++i]) {
case 's':
s = (char *)args_next(args, char *);
while (*s) {
buf[ptr++] = *s++;
}
break;
case 'c':
buf[ptr++] = (char)args_next(args, int);
break;
case 'x':
parse_hex((unsigned long)args_next(args, unsigned long));
break;
case 'd':
parse_num((unsigned long)args_next(args, unsigned long), 10);
break;
case '%':
buf[ptr++] = '%';
break;
default:
buf[ptr++] = fmt[i];
break;
}
}
buf[ptr] = '\0';
args_end(args);
puts(buf);
}