Upload

Digital Research

CPM OPERATING SYSTEMS/CPM.Z80.DE/PERSONAL/PCPM-86/BDOS 4.1/exe2cmd.c

@@ -0,0 +1,193 @@
+/*    Convert the Personal CP/M-86 BDOS (compiled as a small-model EXE) 
+ *    to CMD.
+ *    Copyright (C) 2003, 2007  John Elliott <jce@seasip.demon.co.uk>
+ *
+ *    This library is free software; you can redistribute it and/or
+ *    modify it under the terms of the GNU Library General Public
+ *    License as published by the Free Software Foundation; either
+ *    version 2 of the License, or (at your option) any later version.
+ *
+ *    This library is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *    Library General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Library General Public
+ *    License along with this library; if not, write to the Free
+ *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include <stdio.h>
+#include <string.h>
+
+#define DS_LEN 0xF0	/* Length of data segment (paras) */
+
+int gl_base = 0x60;
+
+/* EXE header (plus first 8 bytes of EXE file) */
+unsigned char exe_header[0x208];
+
+/* CMD header */
+unsigned char cmd_header[0x80];
+
+
+/* Read a word from the EXE header */
+unsigned short peek(int offset)
+{
+    unsigned short l = exe_header[offset];
+    unsigned short h = exe_header[offset + 1];
+    return (h << 8) | l;
+}
+
+/* Add a group to the CMD header */
+void addgroup(int type, unsigned short paras, unsigned short base,
+			  unsigned short minparas, unsigned short maxparas)
+{
+	static unsigned char *group = cmd_header;
+	*group++ = type;
+	*group++ = (paras & 0xFF);
+	*group++ = (paras >> 8);
+	*group++ = (base & 0xFF);
+	*group++ = (base >> 8);
+	*group++ = (minparas & 0xFF);
+	*group++ = (minparas >> 8);
+	*group++ = (maxparas & 0xFF);
+	*group++ = (maxparas >> 8);
+	printf("Group %d: len=%04x base=%04x min=%04x max=%04x\n",
+			type, paras, base, minparas, maxparas);
+}
+
+/* Copy bytes from one file to another. 
+ * TODO: Warn if error. */
+void mvbytes(FILE *fpexe, FILE *fpcmd, long count)
+{
+	int c;
+	
+	while (count)
+	{
+		c = fgetc(fpexe);
+		fputc(c, fpcmd);
+		--count;
+	}
+}
+
+
+int main(int argc, char **argv)
+{
+	FILE *fpexe, *fpcmd;
+	unsigned short cseg,dseg,sseg,dstop;
+	unsigned short dsmin, dsmax, exeparas;
+	unsigned long exelen, dsbytes;
+	long pos;
+	int n;
+
+	if (argc < 3)
+	{
+		fprintf(stderr, "Syntax: exe2cmd <exefile> <cmdfile>\n");
+		return 1;
+	}
+        for (n = 3; n < argc; n++)
+        {
+                if (!strncmp(argv[n], "base=", 5))
+                {
+                        if (!sscanf(&argv[n][5], "%x", &gl_base))
+                        {
+				fprintf(stderr, "base= option incorrect.\n");
+				return 1;
+			}
+		}
+	}
+
+	/* Load EXE header, and extract the segment info. This code depends
+	 * on the word at CS:6 being the length of the code segment in 
+	 * paragraphs. */
+	fpexe = fopen(argv[1], "rb");
+	if (!fpexe)
+	{
+		perror(argv[1]);
+		return 1;
+	} 
+	if (fread(exe_header, 1, sizeof(exe_header), fpexe) < (int)sizeof(exe_header) 
+	/* Check for CP/M-86 BDOS:
+	 *   32 header paragraphs
+	 *   First relocation is at address 6 or less */
+	|| peek(8) != 32 || peek(32) > 6)
+	{
+		fclose(fpexe);
+		fprintf(stderr, "%s is not a BDOS image\n", argv[1]);
+		return 1; 
+	}
+	cseg = 0;
+	dseg = peek(0x206);
+	sseg = peek(14);
+	exelen = 512L * peek(4);
+	if (peek(2)) exelen -= (512 - peek(2));
+	exeparas = (exelen + 15) >> 4;
+/*
+	dstop = exeparas - peek(8);
+	ssparas = dstop - sseg;
+	dsmin = dstop - dseg + peek(10);
+	dsmax = dstop - dseg + peek(12);
+*/
+	/* This is CP/M-86, the DSEG is a fixed size */
+	dsmin = dsmax = DS_LEN;
+	dstop = dseg + DS_LEN;
+	printf("EXE length     = %04lx\n", exelen);
+	printf("EXE header len = %04x\n", peek(8));
+	printf("EXE paras      = %04x\n", exeparas);
+	printf("DS top         = %04x\n", dstop);
+	printf("CS: %04x length %04x\n", cseg, dseg  - cseg);
+	printf("DS: %04x length %04x\n", dseg, dstop - dseg);
+
+	/* Now generate CP/M-86 header. */
+	addgroup(1, dseg  - cseg, 0, dseg - cseg, 0);
+	addgroup(2, dstop - dseg, 0, dsmin, 0);
+
+	fpcmd = fopen(argv[2], "wb");
+	if (fpcmd == NULL)
+	{
+		perror(argv[2]);
+		fclose(fpexe);
+		return 2;
+	}
+	if (fwrite(cmd_header, 1, sizeof(cmd_header), fpcmd) < (int)sizeof(cmd_header)
+	||  fwrite(exe_header+0x200, 1, 8, fpcmd) < 8)
+	{
+		fclose(fpcmd);
+		fclose(fpexe);
+		perror(argv[2]);
+		return 2;
+	}
+	/* Write the code segment. The first 8 bytes have been done. */
+	mvbytes(fpexe, fpcmd, 16L * (dseg - cseg) - 8);
+	/* Write the data segment. */
+	dsbytes = 16L * (dstop - dseg);
+	mvbytes(fpexe, fpcmd, 40);
+	/* Apply fixups to offsets within the data segment */
+	for (n = 0; n < 8; n++)
+	{
+		unsigned seg;
+		if (n == 6)
+		{
+			mvbytes(fpexe, fpcmd, 4);/* Address of DOS module */
+			continue;
+		}
+		mvbytes(fpexe, fpcmd, 2);	/* Offset */
+		fread(exe_header, 1, 2, fpexe);
+		seg = peek(0) + gl_base;
+		fputc(seg & 0xFF, fpcmd);
+		fputc(seg >> 8, fpcmd);
+	}
+	mvbytes(fpexe, fpcmd, dsbytes - 72);
+/* Pad the CMD file out to a whole number of records */
+	pos = ftell(fpcmd);
+	while (pos & 0x7F)
+	{
+		fputc(0, fpcmd);
+		++pos;
+	}
+	fclose(fpcmd);
+	fclose(fpexe);
+	return 0;
+}