Example of setting up malloc heap on extram

apps/heap/heap.c

@@ -0,0 +1,66 @@
+#include "uvm32_target.h"
+#include "malloc_freelist.h"
+
+uint32_t* extram = (uint32_t*)UVM32_EXTRAM_BASE;
+uint32_t extram_len = HEAP_SIZE;
+
+void* memcpy(void* dst, const void* src, int len) {
+    uint8_t* d = (uint8_t*)dst;
+    const uint8_t* s = (const uint8_t*)src;
+    while (len--) {
+        *(d++) = *(s++);
+    }
+    return dst;
+}
+
+void* memset(void* buf, int c, int len) {
+    uint8_t* b = (uint8_t*)buf;
+    while (len--) {
+        *(b++) = c;
+    }
+    return buf;
+}
+
+void* memmove(void* dest, const void* src, size_t len) {
+    char* d = dest;
+    const char* s = src;
+    if (d < s)
+        while (len--)
+            *d++ = *s++;
+    else {
+        const char* lasts = s + (len - 1);
+        char* lastd = d + (len - 1);
+        while (len--)
+            *lastd-- = *lasts--;
+    }
+    return dest;
+}
+
+void force_crash(void) {
+    uint8_t *p = (uint8_t *)0;
+    p[0] = 0;
+}
+
+void main(void) {
+    malloc_addblock(extram, extram_len);
+
+    uint8_t* p1 = fl_malloc(128);
+    if (p1 == NULL) {
+        println("malloc failed");
+    } else {
+        println("malloc ok");
+    }
+    memset(p1, 'a', 128);
+    fl_free(p1);
+
+    uint8_t* p2 = fl_malloc(256);
+    if (p2 == NULL) {
+        println("malloc failed");
+    } else {
+        println("malloc ok");
+    }
+    memset(p2, 'b', 256);
+    fl_free(p2);
+
+    //force_crash();    // allows dump to be inspected
+}