X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=bootcensus;a=blobdiff_plain;f=src%2Fboot%2Fboot2.s;h=2a163e1f650923be53a4d3a3cb8cf93e4d5694a2;hp=572a4f071fda1f45f47304cf02ddd8110d3c4166;hb=27a78ae0ed500338ad3df62e67709ff8cc247e6d;hpb=a7a5ced32b6e0bd417ee7839fac245de29a81fe5

diff --git a/src/boot/boot2.s b/src/boot/boot2.s
index 572a4f0..2a163e1 100644
--- a/src/boot/boot2.s
+++ b/src/boot/boot2.s
@@ -685,15 +685,21 @@ detect_mem_e801:
 	movzx %cx, %eax
 	# first size is in KB, convert to bytes
 	shl $10, %eax
-	mov %eax, 4(%esi)
-	cmp $0, %dx
+	jnc 0f
+	# overflow means it's >4GB, clamp to 4GB
+	mov $0xffffffff, %eax
+0:	mov %eax, 4(%esi)
 	incl boot_mem_map_size
+	cmp $0, %dx
 	jz e801_done
 	movl $0x1000000, 8(%esi)
 	movzx %dx, %eax
 	# second size is in 64kb blocks, convert to bytes
 	shl $16, %eax
-	mov %eax, 12(%esi)
+	jnc 0f
+	# overflow means it's >4GB, clamp to 4GB
+	mov $0xffffffff, %eax
+0:	mov %eax, 12(%esi)
 	incl boot_mem_map_size
 e801_done:
 	clc