Experimental MMAP emulation

Author: mikrosk

mintlib/malloc.c

@@ -1,9 +1,11 @@
-#define HAVE_MMAP 0
-#define HAVE_MORECORE 1
-#define MORECORE_CONTIGUOUS 0
-#define MORECORE_CANNOT_TRIM 1
+#define HAVE_MMAP 1
+#define LACKS_SYS_MMAN_H 1
+#define MMAP_CLEARS 0
+#define HAVE_MORECORE 0
 #define NO_MALLOC_STATS 1
-#define LACKS_TIME_H /* time(0) calls malloc... */
+#define LACKS_TIME_H 1 /* time(0) calls malloc... */
+#define DEFAULT_GRANULARITY 0
+#define MALLOC_ALIGNMENT 16
 
 /*
 Copyright 2023 Doug Lea
@@ -1653,7 +1655,7 @@ unsigned char _BitScanReverse(unsigned long *index, unsigned long mask);
 
 #if HAVE_MMAP
 
-#ifndef WIN32
+#if !defined(WIN32) && !defined(__MINT__)
 #define MUNMAP_DEFAULT(a, s)  munmap((a), (s))
 #define MMAP_PROT            (PROT_READ|PROT_WRITE)
 #if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
@@ -1677,7 +1679,7 @@ static int dev_zero_fd = -1; /* Cached file descriptor for /dev/zero. */
 
 #define DIRECT_MMAP_DEFAULT(s) MMAP_DEFAULT(s)
 
-#else /* WIN32 */
+#elif defined(WIN32)
 
 /* Win32 MMAP via VirtualAlloc */
 static FORCEINLINE void* win32mmap(size_t size) {
@@ -1713,6 +1715,71 @@ static FORCEINLINE int win32munmap(void* ptr, size_t size) {
 #define MMAP_DEFAULT(s)             win32mmap(s)
 #define MUNMAP_DEFAULT(a, s)        win32munmap((a), (s))
 #define DIRECT_MMAP_DEFAULT(s)      win32direct_mmap(s)
+
+#else /* __MINT__ */
+
+#include <mint/osbind.h>
+
+#define MAX_POOL_ENTRIES 256
+static int next_os_pool;
+static struct {
+  void* ptr;
+  size_t size;
+} os_pools[MAX_POOL_ENTRIES];
+
+/* Atari MMAP via Malloc */
+static FORCEINLINE void* atarimmap(size_t size) {
+  void* ptr;
+
+  if (next_os_pool == MAX_POOL_ENTRIES)
+    return MFAIL;
+
+  ptr = (void*)Malloc(size);
+
+  if (ptr != 0) {
+    os_pools[next_os_pool].ptr = ptr;
+    os_pools[next_os_pool].size = size;
+    next_os_pool++;
+    return ptr;
+  }
+
+  return MFAIL;
+}
+
+/* This function supports releasing coalesed segments */
+static FORCEINLINE int atarimunmap(void* ptr, size_t size) {
+  char* cptr = (char*)ptr;
+  while (size) {
+    int found = -1;
+
+    for (int i = 0; i < next_os_pool; ++i) {
+      if (os_pools[i].ptr == cptr) {
+        if (os_pools[i].size <= size)
+          found = i;
+        break;
+      }
+    }
+
+    if (found != -1) {
+      cptr += os_pools[found].size;
+      size -= os_pools[found].size;
+
+      if (--next_os_pool > 0)
+        os_pools[found] = os_pools[next_os_pool];
+
+      Mfree(cptr);
+    }
+    else
+      return -1;
+  }
+
+  return 0;
+}
+
+#define MMAP_DEFAULT(s)             atarimmap(s)
+#define MUNMAP_DEFAULT(a, s)        atarimunmap((a), (s))
+#define DIRECT_MMAP_DEFAULT(s)      MMAP_DEFAULT(s)
+
 #endif /* WIN32 */
 #endif /* HAVE_MMAP */
 
@@ -4169,8 +4236,7 @@ static void* sys_alloc(mstate m, size_t nb) {
       char* end = CMFAIL;
       ACQUIRE_MALLOC_GLOBAL_LOCK();
       br = (char*)(CALL_MORECORE(asize));
-      /* end = (char*)(CALL_MORECORE(0)); */
-      end = br + asize;
+      end = (char*)(CALL_MORECORE(0));
       RELEASE_MALLOC_GLOBAL_LOCK();
       if (br != CMFAIL && end != CMFAIL && br < end) {
         size_t ssize = end - br;