Add boot loader ID to the memdisk info structure

3 files changed, 17 insertions, 5 deletions

diff --git a/memdisk/memdisk.asm b/memdisk/memdisk.asm
index 7acb3cb5..3c33120f 100644
--- a/memdisk/memdisk.asm
+++ b/memdisk/memdisk.asm
@@ -697,7 +697,7 @@ Mover_dummy2:	dd 0, 0, 0, 0		; More space for the BIOS
 
 		alignb 4, db 0
 MemDisk_Info	equ $			; Pointed to by installation check
-MDI_Bytes	dw 26			; Total bytes in MDI structure
+MDI_Bytes	dw 27			; Total bytes in MDI structure
 MDI_Version	db VER_MINOR, VER_MAJOR	; MEMDISK version
 
 PatchArea	equ $			; This gets filled in by the installer
@@ -710,7 +710,10 @@ OldInt13	dd 0			; INT 13h in chain
 OldInt15	dd 0			; INT 15h in chain
 
 OldDosMem	dw 0			; Old position of DOS mem end
+BootLoaderID	db 0			; Boot loader ID from header
 ; ---- MDI structure ends here ---
+		db 0, 0, 0		; pad
+
 MemInt1588	dw 0			; 1MB-65MB memory amount (1K)
 
 Cylinders	dw 0			; Cylinder count
diff --git a/memdisk/memdisk.doc b/memdisk/memdisk.doc
index b67355e2..91e9b3a0 100644
--- a/memdisk/memdisk.doc
+++ b/memdisk/memdisk.doc
@@ -125,7 +125,7 @@ http://www.ctyme.com/rbrown.htm, for a detailed description.
 
 The MEMDISK info structure currently contains:
 
-	[ES:DI]		word	Total size of structure (currently 26 bytes)
+	[ES:DI]		word	Total size of structure (currently 27 bytes)
 	[ES:DI+2]	byte	MEMDISK minor version
 	[ES:DI+3]	byte	MEMDISK major version
 	[ES:DI+4]	dword	Pointer to MEMDISK data in high memory
@@ -134,6 +134,10 @@ The MEMDISK info structure currently contains:
 	[ES:DI+16]	16:16	Old INT 13h pointer
 	[ES:DI+20]	16:16	Old INT 15h pointer
 	[ES:DI+24]	word	Amount of DOS memory before MEMDISK loaded
+	[ES:DI+26]	byte	Boot loader ID
+
+MEMDISK 3.00 and higher has the size of this structure as 27; earlier
+versions had size 26 and did not include the boot loader ID.
 
 In addition, the following fields are available at [ES:0]:
 
diff --git a/memdisk/setup.c b/memdisk/setup.c
index 52754872..f0dd0f4b 100644
--- a/memdisk/setup.c
+++ b/memdisk/setup.c
@@ -70,6 +70,9 @@ struct patch_area {
   uint32_t oldint15;
 
   uint16_t olddosmem;
+  uint8_t  bootloaderid;
+
+  uint8_t  _pad[3];
   uint16_t memint1588;
 
   uint16_t cylinders;
@@ -90,7 +93,7 @@ struct patch_area {
   uint16_t statusptr;
 
   dpt_t dpt;
-};
+} __attribute__((packed));
 
 /* This is the header in the boot sector/setup area */
 struct setup_header {
@@ -118,7 +121,7 @@ struct setup_header {
   uint16_t pad1;
   uint32_t cmd_line_ptr;
   uint32_t initrd_addr_max;
-};
+} __attribute__((packed));
 
 const struct setup_header * const shdr = (struct setup_header *)(LOW_SEG << 4);
 
@@ -571,8 +574,10 @@ uint32_t setup(syscall_t cs_syscall, void *cs_bounce)
   pptr->disksize  = geometry->sectors;
   pptr->diskbuf   = ramdisk_image + geometry->offset;
   pptr->statusptr = (geometry->driveno & 0x80) ? 0x474 : 0x441;
-  pptr->configflags = 0;
 
+  pptr->bootloaderid = shdr->type_of_loader;
+
+  pptr->configflags = 0;
   /* Set config flags */
   if ( getcmditem("ro") != CMD_NOTFOUND ) {
     puts("Marking disk readonly\n");