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Filling out the rest of the page tables

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Thomas Oltmann 2025-07-05 20:18:58 +02:00
parent c41288151a
commit 11cdc51979
1 changed files with 28 additions and 8 deletions
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36
lboot.S
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@ -103,8 +103,7 @@ _gmdone: add $24, %di
ret ret
// paging: Set up initial page tables for long mode // paging: Set up initial page tables for long mode
paging: paging: mov $4*4096, %ecx
mov $4*4096, %ecx
call alloc call alloc
mov %eax, pd_ptr mov %eax, pd_ptr
mov $4096, %ecx mov $4096, %ecx
@ -114,21 +113,42 @@ paging:
call alloc call alloc
mov %eax, pml4_ptr mov %eax, pml4_ptr
// fill PDEs with identity map < 4Gb
mov pd_ptr, %edi mov pd_ptr, %edi
xor %ecx, %ecx xor %ecx, %ecx
_pgnext: mov %ecx, %eax _pgnext: mov %ecx, %eax
shl $21, %eax shl $21, %eax
or $0b110000111, %eax or $0b10000011, %eax
movl %eax, 0(%edi) movl %eax, 0(%edi)
//movl %eax, 0(%edi,%ecx,8) movl $0, 4(%edi)
//movl $0, 4(%edi,%ecx,8) add $8, %edi
inc %ecx inc %ecx
cmp $4*512, %ecx cmp $4*512, %ecx
jne _pgnext jne _pgnext
//mov pml4_ptr, %edi // link to PDs in PDP
//movl 0(%edi) mov pdp_ptr, %edi
//movl $0, 4(%edi) mov pd_ptr, %eax
orl $0b11, %eax
movl %eax, 0(%edi)
movl $0, 4(%edi)
add $0x1000, %eax
movl %eax, 8(%edi)
movl $0, 12(%edi)
add $0x1000, %eax
movl %eax, 16(%edi)
movl $0, 20(%edi)
add $0x1000, %eax
movl %eax, 24(%edi)
movl $0, 28(%edi)
// link to PDP in PML4
mov pml4_ptr, %edi
mov pdp_ptr, %eax
orl $0b11, %eax
movl %eax, 0(%edi)
movl $0, 4(%edi)
ret ret