Module Name: src
Committed By: tsutsui
Date: Fri Dec 8 16:29:04 UTC 2023
Modified Files:
src/sys/arch/i386/stand/bootxx: pbr.S
Log Message:
Replace several magic numbers with macro to describe GPT's hybrid MBR boot.
To generate a diff of this commit:
cvs rdiff -u -r1.23 -r1.24 src/sys/arch/i386/stand/bootxx/pbr.S
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/i386/stand/bootxx/pbr.S
diff -u src/sys/arch/i386/stand/bootxx/pbr.S:1.23 src/sys/arch/i386/stand/bootxx/pbr.S:1.24
--- src/sys/arch/i386/stand/bootxx/pbr.S:1.23 Wed May 11 14:58:00 2022
+++ src/sys/arch/i386/stand/bootxx/pbr.S Fri Dec 8 16:29:04 2023
@@ -1,4 +1,4 @@
-/* $NetBSD: pbr.S,v 1.23 2022/05/11 14:58:00 andvar Exp $ */
+/* $NetBSD: pbr.S,v 1.24 2023/12/08 16:29:04 tsutsui Exp $ */
/*-
* Copyright (c) 2003,2004 The NetBSD Foundation, Inc.
@@ -71,6 +71,10 @@
#define MBR_AFTERBPB 62 /* BPB size in floppy master BR */
#endif
+#define GPT_MAGIC 0x54504721 /* '!GPT' magic on hybrid MBR boot */
+#define GPT_ENTRY_OFF 20 /* GPT part entry in handover struct */
+#define GPT_ENT_LBA_OFF 32 /* ent_lba_start in struct gpt_ent */
+
#ifdef TERSE_ERROR
/*
* Error codes. Done this way to save space.
@@ -127,7 +131,7 @@ start0:
mov %cx, %sp
mov %cx, %es
#ifndef BOOT_FROM_FAT
- cmpl $0x54504721, %eax /* did a GPT hybrid MBR start us? */
+ cmpl $GPT_MAGIC, %eax /* did a GPT hybrid MBR start us? */
je boot_gpt
#endif
mov %cx, %ds
@@ -366,8 +370,9 @@ chs_read:
#ifndef BOOT_FROM_FAT
boot_gpt:
- movl (20+32+0)(%si), %ebp
- movl (20+32+4)(%si), %edi
+ /* DS:SI has a pointer to the hybrid MBR handover structure */
+ movl (GPT_ENTRY_OFF+GPT_ENT_LBA_OFF+0)(%si), %ebp
+ movl (GPT_ENTRY_OFF+GPT_ENT_LBA_OFF+4)(%si), %edi
movw %cx, %ds
movl %ebp, lba_sector + 0
movl %edi, lba_sector + 4
