Use dos/sys compression if the uncompressed kernel is less than 64K. That

makes the compressed kernel about 2K smaller.


git-svn-id: https://svn.code.sf.net/p/freedos/svn/kernel/trunk@1329 6ac86273-5f31-0410-b378-82cca8765d1b

kernel/makefile

@@ -38,9 +38,10 @@ production:     ..\bin\$(TARGET).sys
 
 kernel.sys:	kernel.exe ..\utils\exeflat.exe
 		..\utils\exeflat kernel.exe kernelf.exe 0x60 -S0x10 -S0x74 -E
-		$(XUPX) kernelf.exe
+		if exist kernelf.exe $(XUPX) kernelf.exe
+		if exist kernelf.sys $(XUPX) kernelf.sys
 		..\utils\exeflat kernelf.exe kernel.sys 0x60 $(UPXOPT)
-		-$(RM) kernelf.exe
+		-$(RM) kernelf.exe kernelf.sys
 
 kernel.exe:	$(TARGET).lnk $(OBJS) $(LIBS)
 		$(LINK) @$(TARGET).lnk;

utils/exeflat.c

@@ -48,10 +48,13 @@ large portions copied from task.c
 #include "exe.h"
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <ctype.h>
 
 #define BUFSIZE 32768u
 
+#define KERNEL_START 0x10 /* the kernel code really starts here at 60:10 */
+
 typedef struct {
   UWORD off, seg;
 } farptr;
@@ -82,7 +85,7 @@ void usage(void)
 
 int main(int argc, char **argv)
 {
-  exe_header header;
+  static exe_header header; /* must be initialized to zero */
   int i, j;
   size_t bufsize;
   farptr *reloc;
@@ -92,7 +95,7 @@ int main(int argc, char **argv)
   UBYTE **curbuf;
   FILE *src, *dest;
   short silentSegments[20], silentcount = 0, silentdone = 0;
-  int UPX = FALSE, flat_exe = FALSE;
+  int UPX = FALSE, flat_exe = FALSE, compress_sys_file = FALSE;
 
   /* if no arguments provided, show usage and exit */
   if (argc < 4) usage();
@@ -134,11 +137,23 @@ int main(int argc, char **argv)
   /* arguments left :
      infile outfile relocation offset */
   
+  if ((src = fopen(argv[1], "rb")) == NULL)
+  {
+    if (UPX && strlen(argv[1]) > 3)
+    {
+      strcpy(argv[1] + strlen(argv[1]) - 3, "sys");
       if ((src = fopen(argv[1], "rb")) == NULL)
       {
         printf("Source file %s could not be opened\n", argv[1]);
         return 1;
       }
+      compress_sys_file = TRUE;
+    }
+  }
+  if (compress_sys_file) {
+    fseek(src, 0, SEEK_END);
+    size = ftell(src);
+  } else {
     if (fread(&header, sizeof(header), 1, src) != 1)
     {
       printf("Error reading header from %s\n", argv[1]);
@@ -151,11 +166,6 @@ int main(int argc, char **argv)
       fclose(src);
       return 1;
     }
-  if ((dest = fopen(argv[2], "wb+")) == NULL)
-  {
-    printf("Destination file %s could not be created\n", argv[2]);
-    return 1;
-  }
     start_seg = (UWORD)strtol(argv[3], NULL, 0);
     if (header.exExtraBytes == 0)
       header.exExtraBytes = 0x200;
@@ -167,6 +177,7 @@ int main(int argc, char **argv)
     printf("image size (less header) = %lu = 0x%lx\n", size, size);
     printf("first relocation offset = %u = 0x%u\n", header.exOverlay,
            header.exOverlay);
+  }
 
   /* first read file into memory chunks */
   fseek(src, header.exHeaderSize * 16UL, SEEK_SET);
@@ -194,6 +205,8 @@ int main(int argc, char **argv)
       return 1;
     }
   }
+  if (header.exRelocTable && header.exRelocItems)
+  {
     fseek(src, header.exRelocTable, SEEK_SET);
     reloc = malloc(header.exRelocItems * sizeof(farptr));
     if (reloc == NULL)
@@ -207,6 +220,7 @@ int main(int argc, char **argv)
       printf("Source file read error\n");
       return 1;
     }
+  }
   fclose(src);
   qsort(reloc, header.exRelocItems, sizeof(reloc[0]), compReloc);
   for (i = 0; i < header.exRelocItems; i++)
@@ -233,6 +247,17 @@ int main(int argc, char **argv)
     *spot1 = segment >> 8;
   }
 
+  if (flat_exe) {
+    compress_sys_file = size < 0x10000L;
+    if (compress_sys_file && strlen(argv[2]) > 3)
+      strcpy(argv[2] + strlen(argv[2]) - 3, "sys");
+  }
+
+  if ((dest = fopen(argv[2], "wb+")) == NULL)
+  {
+    printf("Destination file %s could not be created\n", argv[2]);
+    return 1;
+  }
   if (UPX)
   {
     /* UPX HEADER jump $+2+size */
@@ -268,7 +293,7 @@ int main(int argc, char **argv)
     fwrite(JumpBehindCode, 1, 0x20, dest);
   }
 
-  if (flat_exe) {
+  if (flat_exe && !compress_sys_file) {
     /* write header without relocations to file */
     exe_header nheader = header;
     nheader.exRelocItems = 0;
@@ -335,8 +360,22 @@ int main(int argc, char **argv)
     *(short *)&trailer[1] = (short)size + 0x20;
     *(short *)&trailer[23] = header.exInitSS;
     *(short *)&trailer[28] = header.exInitSP;
+    if (compress_sys_file)
+      /* replace by jmp word ptr [6]: ff 26 06 00
+         (the .SYS strategy handler which will unpack) */
+      *(long *)&trailer[30] = 0x000626ffL;
     fwrite(trailer, 1, sizeof trailer, dest);
   }
+  if (flat_exe && compress_sys_file) {
+    /* overwrite first 8 bytes with SYS header */
+    UWORD dhdr[4];
+    fseek(dest, 0, SEEK_SET);
+    for (i = 0; i < 3; i++)
+      dhdr[i] = 0xffff;
+    /* strategy will jump to us, interrupt never called */
+    dhdr[3] = KERNEL_START;
+    fwrite(dhdr, sizeof(dhdr), 1, dest);
+  }
   fclose(dest);
   printf("\nProcessed %d relocations, %d not shown\n",
          header.exRelocItems, silentdone);