From: John Tsiombikas <nuclear@mutantstargoat.com>
Date: Mon, 30 Apr 2018 20:58:20 +0000 (+0300)
Subject: ignore memory ranges above 4gb
X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=bootcensus;a=commitdiff_plain;h=77450ffb9190c6aa2a04bc23792a143b5886e459

ignore memory ranges above 4gb
---

diff --git a/src/boot/boot2.s b/src/boot/boot2.s
index 2a163e1..719f37e 100644
--- a/src/boot/boot2.s
+++ b/src/boot/boot2.s
@@ -615,16 +615,20 @@ e820_looptop:
 	cmp $0x534d4150, %eax
 	jnz e820_fail
 
+	# skip areas starting above 4GB as we won't be able to use them
+	cmpl $0, 4(%edi)
+	jnz e820_skip
+
+	# only care for type 1 (usable ram), otherwise ignore
+	cmpl $1, 16(%edi)
+	jnz e820_skip
+
 	mov buffer, %eax
 	mov $boot_mem_map, %esi
 	mov boot_mem_map_size, %ebp
 	# again, that's [ebp * 8 + esi]
 	mov %eax, (%esi,%ebp,8)
 
-	# only care for type 1 (usable ram), otherwise ignore
-	cmpl $1, 16(%edi)
-	jnz e820_skip
-
 	# skip areas with 0 size (also clamp size to 4gb)
 	# test high 32bits
 	cmpl $0, 12(%edi)