nivirx/stevia
1
0
Fork 0
Code Issues 1 Pull Requests Actions Packages Projects Releases 1 Wiki Activity

refactored and validated MemoryMap funciton

Browse Source
This commit is contained in:
Elaina Claus
2024-10-03 17:41:48 -04:00
parent c8ca94d7ba
commit 2cfe86efac
1 changed files with 10 additions and 16 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
src/stage2/stage2.nasm
View File

@@ -665,26 +665,24 @@ GetMemoryMap:
mov dword [SteviaInfo + SteviaInfoStruct_t.MemoryMapEntries], 0 mov dword [SteviaInfo + SteviaInfoStruct_t.MemoryMapEntries], 0
mov eax, 0xE820 ; select 0xE820 function mov eax, 0xE820 ; select 0xE820 function
mov ebx, 0x0000 ; Continuation value xor ebx, ebx ; Continuation value, 0 for the first call
mov dx, (BIOSMemoryMap >> 4) mov dx, (BIOSMemoryMap >> 4)
mov es, dx mov es, dx
mov di, 0 ; (BIOSMemoryMap >> 4):0 makes di an index into BIOSMemoryMap xor di, di ; (BIOSMemoryMap >> 4):0 makes di an index into BIOSMemoryMap
mov ecx, AddressRangeDescStruct_t_size mov ecx, AddressRangeDescStruct_t_size
mov edx, 0x534D4150 ; 'SMAP' magic mov edx, 0x534D4150 ; 'SMAP' magic
.loop_L1:
int 0x15 int 0x15
jnc GetMemoryMap.no_error jc GetMemoryMap.error
ERROR STAGE2_MM_E820_NO_SUPPORT
.no_error:
inc dword [SteviaInfo + SteviaInfoStruct_t.MemoryMapEntries]
cmp eax, 0x534D4150 cmp eax, 0x534D4150
jne GetMemoryMap.no_smap_returned jne GetMemoryMap.no_smap_returned
.no_error:
inc dword [SteviaInfo + SteviaInfoStruct_t.MemoryMapEntries]
cmp ecx, 20 cmp ecx, 20 ; TODO: maybe this could be handled better than just panicing
jb GetMemoryMap.nonstandard_e820 jb GetMemoryMap.nonstandard_e820 ; non-standard entry found
cmp ebx, 0 cmp ebx, 0
je GetMemoryMap.endp ; 0 in ebx means we have reached the end of memory ranges je GetMemoryMap.endp ; 0 in ebx means we have reached the end of memory ranges
@@ -692,17 +690,13 @@ GetMemoryMap:
add di, AddressRangeDescStruct_t_size ; increment di to next descriptor add di, AddressRangeDescStruct_t_size ; increment di to next descriptor
mov edx, eax ; 'SMAP' to edx mov edx, eax ; 'SMAP' to edx
mov eax, 0xE820 ; select E820 function mov eax, 0xE820 ; select E820 function
jmp GetMemoryMap.loop_L1
int 0x15 .error:
jnc GetMemoryMap.no_error ; carry indicates an error
.other_error:
ERROR STAGE2_MM_E820_MISC_ERR ERROR STAGE2_MM_E820_MISC_ERR
.nonstandard_e820: .nonstandard_e820:
ERROR STAGE2_MM_E820_NONSTANDARD ERROR STAGE2_MM_E820_NONSTANDARD
.no_smap_returned: .no_smap_returned:
ERROR STAGE2_MM_E820_NO_SMAP ERROR STAGE2_MM_E820_NO_SMAP
.endp: .endp:
pop es pop es
__CDECL16_EXIT __CDECL16_EXIT