2 files changed, 94 insertions, 3 deletions
diff --git a/libc/include/stdlib.h b/libc/include/stdlib.h
index a6e27f2..49116df 100644
--- a/libc/include/stdlib.h
+++ b/libc/include/stdlib.h
@@ -1,6 +1,8 @@
 #ifndef _STDLIB_H_
 #define _STDLIB_H_
 
+#include <stddef.h>
+
 /* this is by no means standards-compliant... but who cares? :P */
 
 /* NOT reentrant! */
@@ -14,5 +16,7 @@ char* itoa(int val, int base);
 unsigned int rand(void);
 void srand(unsigned int);
 int abs(int);
+void *malloc(size_t);
+int snprintf(char*, int, const char*, ...);
 
 #endif
diff --git a/libc/stdlib.c b/libc/stdlib.c
index bea3b65..c6a9c3d 100644
--- a/libc/stdlib.c
+++ b/libc/stdlib.c
@@ -1,3 +1,6 @@
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdint.h>
 #include <stdlib.h>
 
 /* adapted from <http://www.strudel.org.uk/itoa/> */
@@ -54,12 +57,96 @@ void srand(unsigned int seed)
     rand_s2 = seed++;
     rand_s3 = seed++;
     /* "warm it up" */
-    rand();
-    rand();
-    rand();
+    for(int i=0;i<10;++i)
+        rand();
 }
 
 int abs(int val)
 {
     return (val<0?-val:val);
 }
+
+void *malloc(size_t sz)
+{
+    static uint8_t mallocbuf[1024*1024*16];
+    static uint8_t *next_ptr = mallocbuf;
+    static int bytes_left = sizeof(mallocbuf);
+    bytes_left -= sz;
+    if(bytes_left < 0)
+        return NULL;
+    else
+    {
+        void *ret = next_ptr;
+        next_ptr += sz;
+        return ret;
+    }
+}
+
+static inline int snputs(char *buf, int idx, int sz, const char *str)
+{
+    while(idx < sz && *str)
+    {
+        buf[idx++] = *str++;
+    }
+    return idx;
+}
+
+static char hex_table[16] = { '0', '1', '2', '3', '4', '5', '6', '7',
+                              '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
+
+static inline int snprint_hex(char *buf, int idx, int sz, unsigned int n)
+{
+    unsigned mask = 0xF0000000;
+    unsigned shift = 28;
+    while(mask && idx < sz)
+    {
+        buf[idx++] = hex_table[(n & mask) >> shift];
+        mask >>= 4;
+        shift -= 4;
+    }
+    return idx;
+}
+
+int snprintf(char *buf, int sz, const char *fmt, ...)
+{
+    va_list ap;
+    va_start(ap, fmt);
+    int i = 0;
+    /* leave room for the null! */
+    sz--;
+    while(*fmt && i < sz)
+    {
+        char ch = *fmt++;
+        switch(ch)
+        {
+        case '%':
+        {
+            switch(*fmt++)
+            {
+            case 'c':
+                buf[i++] = va_arg(ap, int);
+                break;
+            case 's':
+                i = snputs(buf, i, sz, va_arg(ap, const char*));
+                break;
+            case 'x':
+                i =  snprint_hex(buf, i, sz, va_arg(ap, unsigned));
+                break;
+            case 'd':
+                i = snputs(buf, i, sz, itoa(va_arg(ap, unsigned), 10));
+                break;
+            default:
+                i = snputs(buf, i, sz, "snprintf: unknown format\n");
+                break;
+            }
+            break;
+        }
+        default:
+            buf[i++] = ch;
+            break;
+        }
+    }
+    buf[i] = '\0';
+    va_end(ap);
+    return 0;
+}