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)
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
# buffer used by the track loader ... to load tracks.
.align 16
buffer:
+ .global low_mem_buffer
+low_mem_buffer: