From 9783ac97e0d981099476bbbe9ca0e3f242d4f130 Mon Sep 17 00:00:00 2001
From: "E. C. Masloch" <pushbx@ulukai.org>
Date: Wed, 7 Feb 2024 00:18:22 +0100
Subject: [PATCH] boot32, boot32lb: mark magic offsets with macro

---
 boot/boot32.asm   |  7 +++++++
 boot/boot32lb.asm | 11 ++++++++++-
 boot/makefile     |  4 ++--
 3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/boot/boot32.asm b/boot/boot32.asm
index cd5327c..5f72690 100644
--- a/boot/boot32.asm
+++ b/boot/boot32.asm
@@ -28,6 +28,10 @@
 
 ;%define MULTI_SEC_READ  1
 
+                ; NOTE: sys must be updated if magic offsets change
+%assign ISFAT1216DUAL 0
+	%include "magic.mac"
+
 
 segment	.text
 
@@ -96,12 +100,14 @@ real_start:     cld
 		jmp     word 0x1FE0:cont
 
 loadseg_off	dw	0
+	magicoffset "loadseg", 78h
 loadseg_seg	dw	LOADSEG
 
 cont:           mov     ds, ax
                 mov     ss, ax
                 lea     sp, [bp-0x20]
 		sti
+	magicoffset "set unit", 82h
                 mov     [drive], dl     ; BIOS passes drive number in DL
 
 ;                call    print
@@ -401,6 +407,7 @@ no_incr_es:
 
        times   0x01f1-$+$$ db 0
 
+	magicoffset "kernel name", 1F1h
 filename        db      "KERNEL  SYS",0,0
 
 sign            dw      0xAA55
diff --git a/boot/boot32lb.asm b/boot/boot32lb.asm
index 708861a..7f0e48b 100644
--- a/boot/boot32lb.asm
+++ b/boot/boot32lb.asm
@@ -53,6 +53,11 @@
 ;  We support values between 0x60 and 0x200 here, with file size
 ;  of up to 128 KiB (rounded to cluster size). Default is 0x60.
 
+                ; NOTE: sys must be updated if magic offsets change
+%assign ISFAT1216DUAL 0
+	%include "magic.mac"
+
+
 segment	.text
 
 		org	0x7c00		; this is a boot sector
@@ -129,7 +134,9 @@ real_start:	cld
 		rep	movsw		; move boot code to the 0x1FE0:0x0000
 		jmp	word 0x1FE0:cont
 
-loadseg_off	dw	0, LOADSEG
+loadseg_off	dw	0
+	magicoffset "loadseg", 78h
+		dw	LOADSEG
 
 ; -------------
 
@@ -137,6 +144,7 @@ cont:		mov	ds, ax
 		mov	ss, ax		; stack and BP-relative moves up, too
                 lea     sp, [bp-0x20]
 		sti
+	magicoffset "set unit", 82h
 		mov	[drive], dl	; BIOS passes drive number in DL
 
 %ifndef QUIET
@@ -413,6 +421,7 @@ msg_BootError	db "No "
 		; currently, only "kernel.sys not found" gives a message,
 		; but read errors in data or root or fat sectors do not.
 
+	magicoffset "kernel name", 1F1h
 filename	db "KERNEL  SYS"
 
 sign		dw 0, 0xAA55
diff --git a/boot/makefile b/boot/makefile
index e8c4a7e..6bd7f68 100644
--- a/boot/makefile
+++ b/boot/makefile
@@ -13,10 +13,10 @@ fat12com.bin:    boot.asm magic.mac
 fat16com.bin:    boot.asm magic.mac
 		$(NASM) -dISFAT16 $(NASMBOOTFLAGS) boot.asm -l$*.lst -ofat16com.bin
 
-fat32chs.bin:    boot32.asm
+fat32chs.bin:    boot32.asm magic.mac
 		$(NASM) $(NASMBOOTFLAGS) boot32.asm -l$*.lst -ofat32chs.bin
 
-fat32lba.bin:    boot32lb.asm
+fat32lba.bin:    boot32lb.asm magic.mac
 		$(NASM) $(NASMBOOTFLAGS) boot32lb.asm -l$*.lst -ofat32lba.bin
 
 oemfat12.bin:   oemboot.asm