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char out_buf[4096];
int out_pos = 0;
int buf_putc(char c) {
out_buf[out_pos] = c;
out_pos++;
if (out_pos >= 4096) {
syscall(1, 1, out_buf, out_pos);
out_pos = 0;
}
return 1;
}
int buf_flush() {
if (out_pos > 0) {
syscall(1, 1, out_buf, out_pos);
out_pos = 0;
}
return 0;
}
int my_strlen(char *s) {
int n = 0;
while (s[n] != 0) { n++; }
return n;
}
int print_str(char *s) {
int i = 0;
while (s[i] != 0) { buf_putc(s[i]); i++; }
return i;
}
int print_int(int n) {
char tmp[24];
int len = 0;
int neg = n < 0;
if (neg) { buf_putc('-'); n = -n; }
if (n == 0) { buf_putc('0'); return neg + 1; }
while (n > 0) {
tmp[len] = (char)('0' + n % 10);
n = n / 10;
len++;
}
int i = len - 1;
while (i >= 0) { buf_putc(tmp[i]); i--; }
return neg + len;
}
int print_hex(int n) {
char hex[16] = {'0','1','2','3','4','5','6','7',
'8','9','a','b','c','d','e','f'};
if (n == 0) { buf_putc('0'); return 1; }
char tmp[18];
int len = 0;
int u = n;
while (u != 0) {
tmp[len] = hex[u & 15];
u = u / 16;
len++;
}
int i = len - 1;
while (i >= 0) { buf_putc(tmp[i]); i--; }
return len;
}
int my_printf(char *fmt, int a, int b, int c) {
int arg_idx = 0;
int i = 0;
int total = 0;
while (fmt[i] != 0) {
if (fmt[i] != '%') {
buf_putc(fmt[i]);
total++;
i++;
continue;
}
i++; /* skip '%' */
int arg = arg_idx == 0 ? a : (arg_idx == 1 ? b : c);
arg_idx++;
if (fmt[i] == 'd') {
total += print_int(arg);
} else if (fmt[i] == 's') {
total += print_str((char*)arg);
} else if (fmt[i] == 'c') {
buf_putc((char)arg);
total++;
} else if (fmt[i] == 'x') {
total += print_hex(arg);
} else if (fmt[i] == '%') {
buf_putc('%');
total++;
arg_idx--; /* %% doesn't consume an arg */
} else {
buf_putc('%'); buf_putc(fmt[i]);
total += 2;
}
i++;
}
return total;
}
int fact(int n) {
return n <= 1 ? 1 : n * fact(n - 1);
}
int fib(int n) {
if (n <= 1) return n;
return fib(n - 1) + fib(n - 2);
}
int main() {
my_printf("=== JIT printf demo ===\n", 0, 0, 0);
my_printf("Hello, %s!\n", "world", 0, 0);
my_printf("int: %d neg: %d\n", 42, -7, 0);
my_printf("hex: 0x%x\n", 255, 0, 0);
my_printf("char: %c\n", 'A', 0, 0);
my_printf("percent: 100%%\n", 0, 0, 0);
my_printf("\nFactorials:\n", 0, 0, 0);
int i = 1;
while (i <= 8) {
my_printf(" %d! = %d\n", i, fact(i), 0);
i++;
}
my_printf("\nFibonacci:\n ", 0, 0, 0);
i = 0;
while (i < 10) {
my_printf("%d ", fib(i), 0, 0);
i++;
}
my_printf("\n", 0, 0, 0);
my_printf("\nCountdown: ", 0, 0, 0);
int n = 5;
do {
my_printf("%d ", n, 0, 0);
n--;
} while (n > 0);
my_printf("\n", 0, 0, 0);
my_printf("Odd 1-9: ", 0, 0, 0);
i = 0;
while (i < 10) {
i++;
if (i % 2 == 0) continue;
my_printf("%d ", i, 0, 0);
if (i == 9) break;
}
my_printf("\n", 0, 0, 0);
buf_flush();
return 0;
}
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