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move __TINY_DS_ES to unreal_mode function

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also some cleanup
This commit is contained in:
Elaina Claus
2025-09-05 16:18:34 -04:00
parent 534e04ef34
commit 31d05c35e5
1 changed files with 6 additions and 9 deletions
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15
src/stage2/stage2.nasm
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@@ -162,12 +162,6 @@ main:
; enter unreal mode (16 bit code, 32 bit flat memory model) ; enter unreal mode (16 bit code, 32 bit flat memory model)
call EnterUnrealMode call EnterUnrealMode
; set ds, es to the STAGE2_SEGMENT, for our model (generally) ds == es == cs
; fs, gs & ss are all still huge data model, and the macro "__REFLAT_DS_ES" exists
; to easily access data outside of 64KiB boundries using ds/es addressing
__TINY_DS_ES
print_string UnrealMode_OK_info print_string UnrealMode_OK_info
; FAT Driver setup ; FAT Driver setup
@@ -207,7 +201,6 @@ EnterUnrealMode:
mov eax, cr0 mov eax, cr0
or eax, 1 ; set pmode bit or eax, 1 ; set pmode bit
mov cr0, eax ; switch to pmode mov cr0, eax ; switch to pmode
;jmp short $+2 ; i-cache flush
; set cs to a pm code segment (0x8) w/ the following ; set cs to a pm code segment (0x8) w/ the following
jmp 0x0008:EnterUnrealMode.set_segs jmp 0x0008:EnterUnrealMode.set_segs
@@ -219,7 +212,6 @@ EnterUnrealMode:
mov ds, ax ; 10h = 0001_0000b mov ds, ax ; 10h = 0001_0000b
mov es, ax ; es to big data mov es, ax ; es to big data
mov ss, ax ; big stack
mov fs, ax mov fs, ax
mov gs, ax ; extra segments to big data as well mov gs, ax ; extra segments to big data as well
.pm_start: .pm_start:
@@ -230,9 +222,14 @@ EnterUnrealMode:
and eax, ~1 ; toggle bit 1 of cr0 and eax, ~1 ; toggle bit 1 of cr0
mov cr0, eax ; back to realmode mov cr0, eax ; back to realmode
jmp 0x0000:EnterUnrealMode.endp jmp 0x0000:EnterUnrealMode.endp
;jmp short $+2 ; i-cache flush
.endp: .endp:
sti ; re-enable interupts sti ; re-enable interupts
; set ds, es to the STAGE2_SEGMENT, for our model (generally) ds == es == cs
; fs, gs & ss are all still huge data model, and the macro "__REFLAT_DS_ES" exists
; to easily access data outside of 64KiB boundries using ds/es addressing
__TINY_DS_ES
__CDECL16_EXIT __CDECL16_EXIT
ret ret
end_text: end_text: