diff --git a/_posts/2015-08-25-entering-longmode.md b/_posts/2015-08-25-entering-longmode.md index 5dfd3904..00fdd18f 100644 --- a/_posts/2015-08-25-entering-longmode.md +++ b/_posts/2015-08-25-entering-longmode.md @@ -281,7 +281,7 @@ setup_page_tables: ``` Maybe I first explain how an assembly loop works. We use the `ecx` register as a counter variable, just like `i` in a for loop. After mapping the `ecx-th` entry, we increase `ecx` by one and jump to `.map_p2_table` again if it's still smaller 512. -To map a P2 entry we first calculate the start address of its page in `eax`: The `ecx-th` entry needs to be mapped to `ecx * 2MiB`. Then we set the `present`, `writable`, and `huge page` bits and write it to the P2 entry. The address of the `ecx-th` entry in P2 is `p2_table + ecx * 8`, because each entry is 8 bytes large. +To map a P2 entry we first calculate the start address of its page in `eax`: The `ecx-th` entry needs to be mapped to `ecx * 2MiB`. Then we set the `present`, `writable`, and `huge page` bits and write it to the P2 entry. The address of the `ecx-th` entry in P2 is `p2_table + ecx * 8`, because each entry is 8 bytes large. Now the first gigabyte of our kernel is identity mapped and thus accessible through the same physical and virtual addresses.