matos/userspace/libc.c

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C
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2021-11-05 23:02:23 +01:00
#include "libc.h"
#include "minmax.h"
#include "swintr.h"
#include "syscall.h"
int memcmp(const void *aptr, const void *bptr, size_t size)
{
const unsigned char *a = (const unsigned char *)aptr;
const unsigned char *b = (const unsigned char *)bptr;
for (size_t i = 0; i < size; i++) {
if (a[i] < b[i])
return -1;
else if (b[i] < a[i])
return 1;
}
return 0;
}
// Inspirated by https://interrupt.memfault.com/blog/memcpy-newlib-nano
/* Nonzero if either X or Y is not aligned on a "long" boundary. */
#define UNALIGNED(X, Y) \
(((long)X & (sizeof (long) - 1)) | ((long)Y & (sizeof (long) - 1)))
/* How many bytes are copied each iteration of the 4X unrolled loop. */
#define BIGBLOCKSIZE (sizeof (long) << 2)
/* How many bytes are copied each iteration of the word copy loop. */
#define LITTLEBLOCKSIZE (sizeof (long))
/* Threshhold for punting to the byte copier. */
#define TOO_SMALL(LEN) ((LEN) < BIGBLOCKSIZE)
void *memcpy(void *dst0, const void *src0, size_t len0)
{
#if 0
char *dstChar = dst0;
const char *srcChar = src0;
for (size_t i = 0; i < len0; i++) {
*(dstChar++) = *(srcChar++);
}
return dst0;
#else
char *dst = dst0;
const char *src = src0;
long *aligned_dst;
const long *aligned_src;
/* If the size is small, or either SRC or DST is unaligned,
then punt into the byte copy loop. This should be rare. */
if (!TOO_SMALL(len0) && !UNALIGNED(src, dst)) {
aligned_dst = (long *)dst;
aligned_src = (long *)src;
/* Copy 4X long words at a time if possible. */
while (len0 >= BIGBLOCKSIZE) {
*aligned_dst++ = *aligned_src++;
*aligned_dst++ = *aligned_src++;
*aligned_dst++ = *aligned_src++;
*aligned_dst++ = *aligned_src++;
len0 -= BIGBLOCKSIZE;
}
/* Copy one long word at a time if possible. */
while (len0 >= LITTLEBLOCKSIZE) {
*aligned_dst++ = *aligned_src++;
len0 -= LITTLEBLOCKSIZE;
}
/* Pick up any residual with a byte copier. */
dst = (char *)aligned_dst;
src = (char *)aligned_src;
}
while (len0--)
*dst++ = *src++;
return dst0;
#endif
}
void *memset(void *src, int c, size_t n)
{
for (char *ptr = (char *)src; n > 0; n--, ptr++) {
*ptr = (char)c;
}
return src;
}
char *itoa(long long int value, char *str, int base)
{
char *rc;
char *ptr;
char *low;
// Check for supported base.
if (base < 2 || base > 36) {
*str = '\0';
return str;
}
rc = ptr = str;
// Set '-' for negative decimals.
if (value < 0 && base == 10) {
*ptr++ = '-';
}
// Remember where the numbers start.
low = ptr;
// The actual conversion.
do {
// Modulo is negative for negative value. This trick makes abs() unnecessary.
*ptr++ = "zyxwvutsrqponmlkjihgfedcba9876543210123456789abcdefghijklmnopqrstuvwxyz"
[35 + value % base];
value /= base;
} while (value);
// Terminating the string.
*ptr-- = '\0';
// Invert the numbers.
while (low < ptr) {
char tmp = *low;
*low++ = *ptr;
*ptr-- = tmp;
}
return rc;
}
/* K&R */
void reverse(char s[])
{
int c, i, j;
for (i = 0, j = strlen(s) - 1; i < j; i++, j--) {
c = s[i];
s[i] = s[j];
s[j] = c;
}
}
/* K&R */
int strlen(const char s[])
{
int i = 0;
while (s[i] != '\0')
++i;
return i;
}
/* K&R
* Returns <0 if s1<s2, 0 if s1==s2, >0 if s1>s2 */
int strcmp(const char s1[], const char s2[])
{
int i;
for (i = 0; s1[i] == s2[i]; i++) {
if (s1[i] == '\0')
return 0;
}
return s1[i] - s2[i];
}
unsigned int strnlen(const char *s, size_t count)
{
const char *sc;
for (sc = s; count-- && *sc != '\0'; ++sc)
/* nothing */ continue;
return sc - s;
}
char *strzcpy(register char *dst, register const char *src, register int len)
{
int i;
if (len <= 0)
return dst;
for (i = 0; i < len; i++) {
dst[i] = src[i];
if (src[i] == '\0')
return dst;
}
dst[len - 1] = '\0';
return dst;
}
int printf(const char *format, ...)
{
int ret;
va_list ap;
va_start(ap, format);
ret = vprintf(format, ap);
va_end(ap);
return ret;
}
int puts(const char *str)
{
int ret = 0;
while (*str) {
putc(*(str++));
ret++;
}
return ret;
}
// int max is 2^(sizeof(int)*8) which is (2^3)^(sizeof(int)*8/3)
// = 8^(sizeof(int)*8/3) ~ 10^(sizeof(int)*8/3)
#define PRINT_INT(name, type) \
int print##name(type integer, char *str, size_t size) \
{ \
char num[sizeof(integer) * 3]; \
int i = 0; \
int c = 0; \
int ret = 0; \
\
if (integer < 0) { \
if (str) { \
if (size) { \
str[c++] = '-'; \
size--; \
ret++; \
} else { \
return ret; \
} \
} else { \
ret++; \
} \
} \
\
do { \
int digit = integer % 10; \
num[i++] = (digit > 0) ? digit : -digit; \
integer = integer / 10; \
} while (integer != 0); \
\
for (i = i - 1; i >= 0; i--) { \
if (str) { \
if (size) { \
str[c++] = num[i] + '0'; \
size--; \
ret++; \
} else { \
return ret; \
} \
} else { \
ret++; \
} \
} \
return ret; \
}
PRINT_INT(Int, int);
PRINT_INT(Int64, long long int);
int vsnprintf(char *str, size_t size, const char *format, va_list ap)
{
int ret = 0;
int i = 0;
int c = 0;
while (format[i] != '\0' && (size|| !str)) {
switch (format[i]) {
case '%':
switch (format[i + 1]) {
case 'i':
case 'd': {
int s;
int d = va_arg(ap, int);
if (str)
s = printInt(d, &str[c], size);
else
s = printInt(d, NULL, size);
size -= s;
c += s;
ret += s;
break;
}
case 'p':
case 'x': {
char val[sizeof(int) * 2];
unsigned int valIdx = 0;
int d = va_arg(ap, int);
itoa(d, val, 16);
if (str) {
while (val[valIdx]) {
if (size) {
str[c++] = val[valIdx++];
size--;
ret++;
} else {
return ret;
}
}
} else {
ret += strlen(val);
}
break;
}
case 'c': {
if (str) {
int ch = va_arg(ap, int);
str[c++] = ch;
size--;
}
ret++;
break;
}
case 's': {
char *stri = va_arg(ap, char *);
if (!stri)
stri = "[NULL STR]";
if (str) {
while (*stri) {
if (size) {
str[c++] = *(stri++);
size--;
ret++;
} else {
return ret;
}
}
} else {
ret += strlen(stri);
}
break;
}
case '%':
if (str) {
str[c++] = '%';
size--;
}
ret++;
break;
case 'l':
switch (format[i + 2]) {
case 'l':
switch (format[i + 3]) {
case 'd': {
int s;
long long int d = va_arg(ap, long long int);
if (str)
s = printInt64(d, &str[c], size);
else
s = printInt64(d, NULL, size);
size -= s;
c += s;
ret += s;
break;
}
case 'p':
case 'x': {
char val[sizeof(long long int) * 2];
unsigned int valIdx = 0;
long long int d = va_arg(ap, long long int);
itoa(d, val, 16);
if (str) {
while (val[valIdx]) {
if (size) {
str[c++] = val[valIdx++];
size--;
ret++;
} else {
return ret;
}
}
} else {
ret += strlen(val);
}
break;
}
}
i++;
break;
case 'i':
case 'd': {
int s;
long int d = va_arg(ap, long int);
if (str)
s = printInt64(d, &str[c], size);
else
s = printInt64(d, NULL, size);
size -= s;
c += s;
ret += s;
break;
}
}
i++;
break;
}
i++;
break;
default:
if (str) {
str[c++] = format[i];
size--;
}
ret++;
}
i++;
}
if (str) {
if (size) {
str[c++] = '\0';
size--;
} else {
if (c > 0) {
str[c - 1] = '\0';
}
}
}
return ret;
}
int vprintf(const char *fmt, va_list ap)
{
char tmp[256];
int idx = 0;
int ret = vsnprintf(tmp, sizeof(tmp), fmt, ap);
while (ret > 0 && tmp[idx]) {
putc(tmp[idx++]);
}
return ret;
}
int asprintf(char **strp, const char *fmt, ...)
{
int ret;
va_list ap;
va_start(ap, fmt);
ret = vasprintf(strp, fmt, ap);
va_end(ap);
return ret;
}
int vasprintf(char **strp, const char *fmt, va_list ap)
{
int n = 0;
size_t size = 0;
char p[256]; //TODO replace by malloc
/* Determine required size */
n = vsnprintf(p, size, fmt, ap);
if (n < 0)
return -1;
/* One extra byte for '\0' */
size = min(256U,(size_t)n + 1);
n = vsnprintf(p, size, fmt, ap);
if (n < 0) {
return -1;
}
*strp = p;
return size;
}
int syscall3(int id, unsigned int arg1, unsigned int arg2, unsigned int arg3)
{
int ret;
asm volatile("movl %1,%%eax \n"
"movl %2,%%ebx \n"
"movl %3,%%ecx \n"
"movl %4,%%edx \n"
"int %5\n"
"movl %%eax, %0"
: "=g"(ret)
: "g"(id), "g"(arg1), "g"(arg2), "g"(arg3), "i"(SYSCALL_INTR_NB)
: "eax", "ebx", "ecx", "edx");
return ret;
}
int syscall2(int id, unsigned int arg1, unsigned int arg2)
{
return syscall3(id, arg1, arg2, 0);
}
int syscall1(int id, unsigned int arg1)
{
return syscall3(id, arg1, 0, 0);
}
int syscall0(int id)
{
return syscall3(id, 0, 0, 0);
}
void _exit(int status)
{
syscall1(SYSCALL_ID_EXIT, status);
}
int putc(const int c){
return syscall1(SYSCALL_ID_PUTC, c);
}
void yolo()
{
syscall0(SYSCALL_ID_YOLO);
}
2021-11-06 00:13:40 +01:00
char readc()
{
return syscall0(SYSCALL_ID_READ);
}
char readcBlock()
{
char c = 0;
do {
c = readc();
} while (c == 0);
return c;
}
int readline(char *buf, int size)
{
int i = 0;
for (; i < size - 1; i++) {
char key = readcBlock();
if (key == '\n')
break;
if(key == '\b' && i>=1){
buf[i-1] = '\0';
i-=2;
}
buf[i] = key;
}
buf[i] = '\0';
return i == (size-1);
}