Add libc

Author: luka177

libc.c

@@ -0,0 +1,297 @@
+#include "libc.h"
+
+#include <stdarg.h>
+
+void _putchar(char character);
+
+/** \brief Division result
+ *  \sa uidiv
+ */
+typedef struct uidiv_result {
+    u32_t quo;  ///< Quotient
+    u32_t rem;  ///< Remainder
+} uidiv_result_t;
+
+/********************************************//**
+ *  \brief Unsigned integer division
+ *
+ *  ARM does not have native division support
+ *  \returns Result of operation or zero if
+ *  dividing by zero.
+ ***********************************************/
+uidiv_result_t
+uidiv (u32_t num,   ///< Numerator
+       u32_t dem)   ///< Denominator
+{
+    u32_t tmp = dem;
+    uidiv_result_t ans = {0};
+
+    if (dem == 0)
+    {
+        // TODO: Somehow make error
+        return ans;
+    }
+
+    while (tmp <= num >> 1)
+    {
+        tmp <<= 1;
+    }
+
+    do
+    {
+        if (num >= tmp)
+        {
+            num -= tmp;
+            ans.quo++;
+        }
+        ans.quo <<= 1;
+        tmp >>= 1;
+    } while (tmp >= dem);
+    ans.quo >>= 1;
+    ans.rem = num;
+
+    return ans;
+}
+
+void*  memset(void*  dst, int c, u32_t n)
+{
+    char*  q   = dst;
+    char*  end = q + n;
+
+    for (;;) {
+        if (q >= end) break; *q++ = (char) c;
+        if (q >= end) break; *q++ = (char) c;
+        if (q >= end) break; *q++ = (char) c;
+        if (q >= end) break; *q++ = (char) c;
+    }
+
+  return dst;
+}
+
+u32_t
+strlen(const char *str)
+{
+    const char *s;
+
+    for (s = str; *s; ++s)
+        ;
+    return (s - str);
+}
+
+// thanks naehrwert for the tiny printf
+static void _putn(char **p_str, u32_t x, u32_t base, char fill, int fcnt, int upper)
+{
+    char buf[65];
+    char *digits;
+    char *p;
+    int c = fcnt;
+    uidiv_result_t div_res;
+
+    if (upper)
+        digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+    else
+        digits = "0123456789abcdefghijklmnopqrstuvwxyz";
+
+    if(base > 36)
+        return;
+
+    p = buf + 64;
+    *p = 0;
+    do
+    {
+        c--;
+        div_res = uidiv (x, base);
+        *--p = digits[div_res.rem];
+        x = div_res.quo;
+    }while(x);
+
+    if(fill != 0)
+    {
+        while(c > 0)
+        {
+            *--p = fill;
+            c--;
+        }
+    }
+
+    for(; *p != '\0'; *((*p_str)++) = *(p++));
+}
+
+/********************************************//**
+ *  \brief Simple @c vsprintf
+ *
+ *  Only supports %c, %s, %u, %x, %X with
+ *  optional zero padding.
+ *  Always returns zero.
+ ***********************************************/
+int vsprintf (char *str, const char *fmt, va_list ap)
+{
+    char *s;
+    char c, fill;
+    int fcnt;
+    u32_t n;
+
+    while(*fmt)
+    {
+        if(*fmt == '%')
+        {
+            fmt++;
+            fill = 0;
+            fcnt = 0;
+            if((*fmt >= '0' && *fmt <= '9') || *fmt == ' ')
+                if(*(fmt+1) >= '0' && *(fmt+1) <= '9')
+                {
+                    fill = *fmt;
+                    fcnt = *(fmt+1) - '0';
+                    fmt++;
+                    fmt++;
+                }
+            switch(*fmt)
+            {
+            case 'c':
+                c = va_arg(ap, u32_t);
+                *(str++) = c;
+                break;
+            case 's':
+                s = va_arg(ap, char *);
+                for(; *s != '\0'; *(str++) = *(s++));
+                break;
+            case 'u':
+                n = va_arg(ap, u32_t);
+                _putn(&str, n, 10, fill, fcnt, 0);
+                break;
+            case 'x':
+                n = va_arg(ap, u32_t);
+                _putn(&str, n, 16, fill, fcnt, 0);
+                break;
+            case 'X':
+                n = va_arg(ap, u32_t);
+                _putn(&str, n, 16, fill, fcnt, 1);
+                break;
+            case '%':
+                *(str++) = '%';
+                break;
+            case '\0':
+                goto out;
+            default:
+                *(str++) = '%';
+                *(str++) = *fmt;
+                break;
+            }
+        }
+        else
+            *(str++) = *fmt;
+        fmt++;
+    }
+
+    out:
+    *str = '\0';
+    return 0;
+}
+
+/********************************************//**
+ *  \brief Simple @c sprintf
+ *
+ *  Only supports %c, %s, %u, %x, %X with
+ *  optional zero padding.
+ *  Always returns zero.
+ ***********************************************/
+int sprintf (char *str, const char *format, ...)
+{
+    va_list arg;
+
+    va_start (arg, format);
+    vsprintf (str, format, arg);
+    va_end (arg);
+    return 0;
+}
+
+int putchar(int c) {
+    _putchar(c);
+    return 0;
+}
+
+int printf(const char *format, ...) {
+    char line[512] = {0};
+    va_list arg;
+
+    va_start (arg, format);
+    vsprintf (line, format, arg);
+    va_end (arg);
+
+    for (char *c = line; *c; ++c) {
+        putchar(*c);
+    }
+
+    return 0;
+}
+
+int puts(const char *line) {
+    for (const char *c = line; *c; ++c) {
+        putchar(*c);
+    }
+    putchar('\n');
+    return 0;
+}
+
+char *
+strcpy(char *to, const char *from)
+{
+    char *save = to;
+
+    for (; (*to = *from) != '\0'; ++from, ++to);
+    return(save);
+}
+
+char *
+strcat(char *dest, const char *src)
+{
+    strcpy(dest + strlen(dest), src);
+    return dest;
+}
+
+/*
+ * Compare strings.
+ */
+int
+strcmp(const char *s1, const char *s2)
+{
+    while (*s1 == *s2++)
+        if (*s1++ == 0)
+            return (0);
+    return (*(unsigned char *)s1 - *(unsigned char *)--s2);
+}
+
+int
+strncmp(const char *s1, const char *s2, u32_t n)
+{
+    if (n == 0)
+        return (0);
+    do {
+        if (*s1 != *s2++)
+            return (*(unsigned char *)s1 - *(unsigned char *)--s2);
+        if (*s1++ == 0)
+            break;
+    } while (--n != 0);
+    return (0);
+}
+
+void *memcpy(void *dest, const void *src, size_t n)
+{
+    char *dp = dest;
+    const char *sp = src;
+    while (n--)
+        *dp++ = *sp++;
+    return dest;
+}
+
+int memcmp(const void* s1, const void* s2,size_t n)
+{
+    const unsigned char *p1 = s1, *p2 = s2;
+    while(n--)
+        if( *p1 != *p2 )
+            return *p1 - *p2;
+        else
+            p1++,p2++;
+    return 0;
+}

libc.h

@@ -0,0 +1,28 @@
+#pragma once
+
+/** \name Fixed width integers
+ *  @{
+ */
+typedef unsigned char u8_t;             ///< Unsigned 8-bit type
+typedef unsigned short int u16_t;       ///< Unsigned 16-bit type
+typedef unsigned int u32_t;             ///< Unsigned 32-bit type
+typedef unsigned long long u64_t;        ///< Unsigned 64-bit type
+
+typedef u64_t u64;
+typedef u32_t u32;
+typedef u16_t u16;
+typedef u8_t u8;
+
+typedef unsigned size_t;
+
+size_t strlen(const char *str);
+int printf(const char *format, ...);
+int sprintf (char *str, const char *format, ...);
+char *strcpy(char *to, const char *from);
+int strncmp(const char *s1, const char *s2, u32_t n);
+void*  memset(void*  dst, int c, u32_t n);
+void *memcpy(void *dest, const void *src, size_t n);
+int strcmp(const char *s1, const char *s2);
+
+int puts(const char *line);
+int memcmp(const void* s1, const void* s2,size_t n);