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stick mmap info in SteviaInfo

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This commit is contained in:
Elaina Claus
2025-09-17 16:24:27 -04:00
parent 8b0b73d8a4
commit 59bc1afb7c
2 changed files with 25 additions and 87 deletions
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20
include/BIOS/func/E820_memory_map.nasm
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@@ -33,35 +33,27 @@ struc AddressRangeDescStruct_t
.ExtType resd 1
endstruc
; !!! this procedure changes ES !!!
ALIGN 4, db 0x90
GetMemoryMap:
__CDECL16_PROC_ENTRY
push es ; save segment register
.func:
mov dword [SteviaInfo + SteviaInfoStruct_t.MemoryMapEntries], 0
mov word [SteviaInfo + SteviaInfoStruct_t.u16_E820MMapEntryCount], 0
xor ebx, ebx ; Continuation value, 0 for the first call
mov dx, BIOSMemoryMap
shr dx, 4
mov es, dx
xor di, di ; (BIOSMemoryMap >> 4):0 makes di an index into BIOSMemoryMap
mov di, BIOSMemoryMap ; destination is es:di, es should == ds
mov ecx, AddressRangeDescStruct_t_size ; hard request ACPI 3.0 table versions (24 bytes)
.loop_L1:
mov eax, 0x0000E820 ; select 0xE820 function
mov edx, 0x534D4150 ; 'SMAP' magic
clc ; clear carry
int 0x15
int 0x15 ; data will be stored at es:di by e820 call
jc GetMemoryMap.error
cmp eax, 0x534D4150
jne GetMemoryMap.no_smap_returned
.no_error:
mov eax, dword [SteviaInfo + SteviaInfoStruct_t.MemoryMapEntries]
add eax, 1
mov dword [SteviaInfo + SteviaInfoStruct_t.MemoryMapEntries], eax
inc word [SteviaInfo + SteviaInfoStruct_t.u16_E820MMapEntryCount]
cmp ecx, 20 ; TODO: maybe this could be handled better than just panicing
jb GetMemoryMap.nonstandard_e820 ; non-standard entry found
@@ -89,7 +81,7 @@ GetMemoryMap:
PrintMemoryMap:
__CDECL16_PROC_ENTRY
.func:
mov eax, dword [SteviaInfo + SteviaInfoStruct_t.MemoryMapEntries]
mov eax, dword [SteviaInfo + SteviaInfoStruct_t.u16_E820MMapEntryCount]
cmp eax, 0
je PrintMemoryMap.endp ; if entries == 0, exit