--- /dev/null
+/* SCCS Id: @(#)ovlinit.c 3.3 94/03/20 */
+/* Copyright (c) NetHack PC Development Team 1995 */
+/* NetHack may be freely redistributed. See license for details. */
+
+#include "hack.h"
+#include <dos.h>
+#include <stdio.h>
+
+
+#ifdef _MSC_VER
+
+#define RESERVED_PARAGRAPHS 5120 /* leave 80K for malloc and inits */
+ /* subject to change before release */
+
+/*
+ * memavail() Returns the amount of RAM available (in paragraphs which are 16
+ * bytes) - the amount to be reserved for heap allocations.
+ *
+ */
+unsigned memavail(minovl)
+unsigned minovl; /* minimum size of overlay heap */
+{
+ unsigned available;
+
+ unsigned farparaavail;
+ unsigned tmp;
+
+ /*
+ * _dos_allocmem will return the maximum block size available.
+ * It uses DOS (int 21h) service 0x48.
+ */
+
+ _dos_allocmem(0xFFFF, &farparaavail);
+ available = farparaavail - RESERVED_PARAGRAPHS;
+ tmp = RESERVED_PARAGRAPHS + minovl;
+ if (farparaavail < tmp) {
+ panic("Not enough free RAM to begin a game of NetHack (%ld bytes)",
+ (long)((long)tmp * 16L));
+ }
+ return available;
+}
+#endif /*_MSC_VER*/
+
+#ifdef __BORLANDC__
+
+#define RSRVD_MALLOC 65 * 1024L /* malloc() calls use about 65K */
+#define RSRVD_CRTL 50 * 1024L /* C runtime library uses 50K */
+#define RSRVD_TOTAL 115 * 1024L /* reserved for use in malloc() */
+ /* as well as by C runtime library */
+ /* routines which allocate memory */
+ /* after this routine runs. */
+#define MIN_OVRBUF 30 * 1024L /* Overlay buffer gets minimum of */
+#define MAX_OVRBUF 200 * 1024L /* 30K and maximum of 200K. */
+
+#define RESIZE_OVL
+#ifdef RESIZE_OVL
+
+extern unsigned _ovrbuffer = 0; /* Use default size initially */
+unsigned appFail = 0; /* Fail flag if not enough RAM */
+unsigned memAlloc = 0;
+unsigned long ProgramSize;
+unsigned long runAlloc;
+unsigned far *mem_top;
+unsigned total;
+signed long tmpbuffer;
+int emsstatus;
+int xmsstatus;
+
+void NDECL(_resizeOvrBuffer);
+
+void _resizeOvrBuffer()
+{
+ mem_top = (unsigned far *) MK_FP( _psp, 0x02 );
+ total = *mem_top - _psp;
+
+ ProgramSize = * (unsigned far *) MK_FP( _psp - 1, 0x03 );
+ tmpbuffer = total - ProgramSize - RSRVD_TOTAL / 16;
+ memAlloc = min (MAX_OVRBUF / 16, tmpbuffer);
+ if (tmpbuffer >= MIN_OVRBUF / 16)
+ _ovrbuffer = memAlloc;
+ else {
+ _ovrbuffer = 1;
+ appFail = 1;
+ };
+
+
+/*
+ * Remember, when inside this code, nothing has been setup on
+ * the system, so do NOT call any RTL functions for I/O or
+ * anything else that might rely on a startup function. This
+ * includes accessing any global objects as their constructors
+ * have not been called yet.
+ */
+
+}
+
+#pragma startup _resizeOvrBuffer 0 /* Put function in table */
+
+void
+startup ()
+{
+ if (appFail) {
+ printf ("NetHack fits in memory, but it cannot allocate memory");
+ printf (" for the overlay buffer\nand the runtime functions. ");
+ printf ("Please free up just %ld more bytes.",
+ (long)(MIN_OVRBUF - tmpbuffer * 16L));
+ exit (-1);
+ } else {
+
+ /* Now try to use expanded memory for the overlay manager */
+ /* If that doesn't work, we revert to extended memory */
+
+ emsstatus = _OvrInitEms (0, 0, 0);
+#ifdef RECOGNIZE_XMS
+ xmsstatus = (emsstatus) ? _OvrInitExt (0, 0) : -1;
+#endif
+
+ }
+}
+
+void
+show_borlandc_stats(win)
+winid win;
+{
+ char buf[BUFSZ];
+
+ putstr(win, 0, "");
+ putstr(win, 0, "");
+ putstr(win, 0, "Memory usage stats"); putstr(win, 0, "");
+ putstr(win, 0, "");
+ Sprintf (buf, "Overlay buffer memory allocation: %ld bytes.",
+ memAlloc * 16L); putstr(win, 0, buf);
+ Sprintf (buf, "_ovrbuffer = %u.", _ovrbuffer); putstr(win, 0, buf);
+ Sprintf (buf, "Startup memory usage: 0x%X", ProgramSize);
+ putstr(win, 0, buf);
+ runAlloc = * (unsigned far *) MK_FP( _psp - 1, 0x03);
+ Sprintf (buf, "Current memory usage: 0x%X", runAlloc);
+ putstr(win, 0, buf);
+ if (emsstatus) Sprintf (buf, "EMS search failed (%d).", emsstatus);
+ else Sprintf (buf, "EMS search successful.");
+ putstr(win, 0, buf);
+#ifdef RECOGNIZE_XMS
+ if (xmsstatus) Sprintf (buf, "XMS search failed (%d).", xmsstatus);
+ else Sprintf (buf, "XMS search successful.");
+ putstr(win, 0, buf);
+#endif
+
+
+}
+
+#endif /* #ifdef RESIZE_OVL */
+#endif /* #ifdef __BORLANDC__ */
+
+/*ovlinit.c*/