Add support for creating V7 executables

Only really usable for executables; relocatables can still happily use
the new (Linux, ELKS, 386BSD) format. Probably only impure executables
will be correctly generated; moreover without a symbol table.

5 files changed, 95 insertions, 0 deletions

diff --git a/ld/globvar.h b/ld/globvar.h
index 84cf8ff..5663cc0 100644
--- a/ld/globvar.h
+++ b/ld/globvar.h
@@ -13,6 +13,9 @@ EXTERN struct redlist *redfirst;	/* first on list of redefined symbols */
 /* K&R _explicitly_ says extern followed by public is OK */
 extern char hexdigit[];			/* constant */
 extern int  headerless;			/* Don't output header on exe */
+#ifndef VERY_SMALL_MEMORY
+extern int  v7;				/* Generate an UNIX v7 a.out header */
+#endif
 #ifndef MSDOS
 extern int  cpm86;			/* Generate CP/M-86 CMD header */
 #endif
diff --git a/ld/ld.c b/ld/ld.c
index 2d31f13..a021e57 100644
--- a/ld/ld.c
+++ b/ld/ld.c
@@ -19,6 +19,9 @@ PUBLIC bin_off_t text_base_value = 0;	/* XXX */
 PUBLIC bin_off_t data_base_value = 0;	/* XXX */
 PUBLIC bin_off_t heap_top_value  = 0;	/* XXX */
 PUBLIC int headerless = 0;
+#ifndef VERY_SMALL_MEMORY
+PUBLIC int v7 = 0;
+#endif
 #ifndef MSDOS
 PUBLIC int cpm86 = 0;
 #endif
@@ -125,6 +128,9 @@ char **argv;
 	    case 'c':		/* Write header in CP/M-86 format */
 #endif
 	    case 'y':		/* Use a newer symbol table */
+#ifndef VERY_SMALL_MEMORY
+	    case '7':		/* Produce a UNIX v7 a.out header */
+#endif
 		if (arg[2] == 0)
 		    flag[(int) arg[1]] = TRUE;
 		else if (arg[2] == '-' && arg[3] == 0)
@@ -237,6 +243,11 @@ char **argv;
     headerless = flag['d'];
     if( headerless ) flag['s'] = 1;
 
+#ifndef VERY_SMALL_MEMORY
+    /* UNIX seventh edition executables */
+    v7 = flag['7'];
+#endif
+
 #ifndef MSDOS
     /* CP/M-86 executables can't use symbols. */
     cpm86 = flag['c'];
diff --git a/ld/v7_aout.h b/ld/v7_aout.h
new file mode 100644
index 0000000..020079b
--- /dev/null
+++ b/ld/v7_aout.h
@@ -0,0 +1,26 @@
+/* Header format of 16-bit
+ * Seventh edition UNIX executables */
+
+#ifndef _V7_A_OUT_H
+#define _V7_A_OUT_H
+
+#define V7_MAGIC4 0405	/* v7 overlay */
+#define V7_OMAGIC 0407	/* I&D in one segment (impure) */
+#define V7_NMAGIC 0410	/* read-only text */
+#define V7_MAGIC3 0411	/* v7 separate I&D (pure) */
+#define V7_ZMAGIC 0413	/* v8 demand load */
+
+#define V7_HEADERLEN 16
+
+struct  v7_exec {
+    short magic;
+    unsigned short textsize;
+    unsigned short datasize;
+    unsigned short bsssize;
+    unsigned short symtabsize;
+    unsigned short entry;
+    unsigned short pad;
+    unsigned short noreloc;
+};
+
+#endif /* _V7_A_OUT_H */
diff --git a/ld/writex86.c b/ld/writex86.c
index eaf4881..feb7b55 100644
--- a/ld/writex86.c
+++ b/ld/writex86.c
@@ -4,6 +4,9 @@
 
 #include "syshead.h"
 #include "x86_aout.h"
+#ifndef VERY_SMALL_MEMORY
+#include "v7_aout.h"
+#endif
 #ifndef MSDOS
 #include "x86_cpm86.h"
 #endif
@@ -23,7 +26,11 @@
 #ifdef MSDOS
 #  define FILEHEADERLENGTH (headerless?0:A_MINHDR)
 #else
+# ifdef VERY_SMALL_MEMORY
 #  define FILEHEADERLENGTH (headerless?0:(cpm86?CPM86_HEADERLEN:A_MINHDR))
+# else
+#  define FILEHEADERLENGTH (headerless?0:(cpm86?CPM86_HEADERLEN:(v7?V7_HEADERLEN:A_MINHDR)))
+# endif
 #endif
 				/* part of header not counted in offsets */
 #define DPSEG 2
@@ -83,6 +90,9 @@ FORWARD void symres P((char *name));
 FORWARD void setseg P((fastin_pt newseg));
 FORWARD void skip P((unsigned countsize));
 FORWARD void writeheader P((void));
+#ifndef VERY_SMALL_MEMORY
+FORWARD void v7header P((void));
+#endif
 #ifndef MSDOS
 FORWARD void cpm86header P((void));
 #endif
@@ -336,6 +346,11 @@ bool_pt argxsym;
     if (cpm86) cpm86header();
     else
 #endif
+#ifndef VERY_SMALL_MEMORY
+    if (v7)
+       v7header();
+    else
+#endif
        writeheader();
     for (modptr = modfirst; modptr != NUL_PTR; modptr = modptr->modnext)
 	if (modptr->loadflag)
@@ -669,6 +684,43 @@ PRIVATE void writeheader()
        writeout((char *) &header, FILEHEADERLENGTH);
 }
 
+#ifndef VERY_SMALL_MEMORY
+PRIVATE void v7header()
+{
+    struct v7_exec header;
+
+    if( sizeof header != FILEHEADERLENGTH )
+       fatalerror("Executable miscompiled, computed wrong header size");
+
+    memset(&header, 0, sizeof header);
+
+    if( bits32 )
+       fatalerror("V7 a.out format is for 16-bit only");
+
+    offtocn((char *) &header.magic, sepid ? V7_MAGIC3 : V7_OMAGIC,
+            sizeof header.magic);
+
+    offtocn((char *) &header.textsize, etextpadoff - btextoffset,
+            sizeof header.textsize);
+    offtocn((char *) &header.datasize, edataoffset - bdataoffset,
+            sizeof header.datasize);
+    offtocn((char *) &header.bsssize, endoffset - edataoffset,
+            sizeof header.bsssize);
+
+    if( !stripflag )
+       fatalerror("Symbol table not implemented for V7 yet");
+
+    if( uzp )
+       fatalerror("No QMAGIC for V7");
+
+    offtocn((char *) &header.entry, entryfirst->elsymptr->value,
+            sizeof header.entry);
+
+    if( FILEHEADERLENGTH )
+       writeout((char *) &header, FILEHEADERLENGTH);
+}
+#endif
+
 PRIVATE void writenulls(count)
 bin_off_t count;
 {
diff --git a/man/ld86.1 b/man/ld86.1
index 7a87473..7665e65 100644
--- a/man/ld86.1
+++ b/man/ld86.1
@@ -38,6 +38,9 @@ produce header with 16-bit magic
 produce header with 32-bit magic
 .\"and use library subdir i386 for -lx
 .TP
+.B -7
+produce Seventh Edition UNIX a.out header.
+.TP
 .B -d
 delete the header from the output file, used for MSDOS COM files. As a side
 effect this also includes -s as there's nowhere to put a symbol table.