rulimine/stage2/lib/blib.c
2020-12-09 13:02:05 +01:00

113 lines
2.3 KiB
C

#include <stdint.h>
#include <stddef.h>
#include <stdarg.h>
#include <lib/libc.h>
#include <lib/blib.h>
#include <lib/print.h>
#include <lib/trace.h>
uint8_t boot_drive;
int boot_partition = -1;
bool parse_resolution(int *width, int *height, int *bpp, const char *buf) {
int res[3] = {0};
const char *first = buf;
for (int i = 0; i < 3; i++) {
const char *last;
int x = strtoui(first, &last, 10);
if (first == last)
break;
res[i] = x;
if (*last == 0)
break;
first = last + 1;
}
if (res[0] == 0 || res[1] == 0)
return false;
if (res[2] == 0)
res[2] = 32;
*width = res[0], *height = res[1], *bpp = res[2];
return true;
}
// This integer sqrt implementation has been adapted from:
// https://stackoverflow.com/questions/1100090/looking-for-an-efficient-integer-square-root-algorithm-for-arm-thumb2
uint64_t sqrt(uint64_t a_nInput) {
uint64_t op = a_nInput;
uint64_t res = 0;
uint64_t one = (uint64_t)1 << 62;
// "one" starts at the highest power of four <= than the argument.
while (one > op) {
one >>= 2;
}
while (one != 0) {
if (op >= res + one) {
op = op - (res + one);
res = res + 2 * one;
}
res >>= 1;
one >>= 2;
}
return res;
}
uint8_t bcd_to_int(uint8_t val) {
return (val & 0x0f) + ((val & 0xf0) >> 4) * 10;
}
__attribute__((noreturn)) void panic(const char *fmt, ...) {
asm volatile ("cli" ::: "memory");
va_list args;
va_start(args, fmt);
print("\033[31mPANIC\033[37;1m\033[40m: ");
vprint(fmt, args);
va_end(args);
print("\n");
print_stacktrace(NULL);
for (;;) {
asm volatile ("hlt" ::: "memory");
}
}
int digit_to_int(char c) {
if (c >= 'a' && c <= 'f') {
return (c - 'a') + 10;
}
if (c >= 'A' && c <= 'F') {
return (c - 'A') + 10;
}
if (c >= '0' && c <= '9'){
return c - '0';
}
return -1;
}
uint64_t strtoui(const char *s, const char **end, int base) {
uint64_t n = 0;
for (size_t i = 0; ; i++) {
int d = digit_to_int(s[i]);
if (d == -1) {
if (end != NULL)
*end = &s[i];
break;
}
n = n * base + d;
}
return n;
}