aseg with a working C execution environment

[netwatch.git] / aseg / aseg.asm

diff --git a/aseg/aseg.asm b/aseg/aseg.asm
index f10955a6f05cd7f7b0b0dd9c4c987ec9c631e503..ee83272652e66bf3595dd8129eecc6c857b2efb3 100644 (file)
--- a/aseg/aseg.asm
+++ b/aseg/aseg.asm
@@ -1,8 +1,6 @@
        org 0xA8000
 [bits 16]
 entry:
-;      mov al, 0x01            ; Say where we are.
-;      out 0x80, al
        mov ax, 0xA800
        mov ds, ax              ; Take us out of flat unreal mode, and
        mov es, ax              ; put us in true real mode.
@@ -11,38 +9,25 @@ entry:
        mov ss, ax
        jmp 0xA800:(entry2-0xA8000)     ; Long jump to a correct cs.
 entry2:
-;      mov al, 0x02
-;      out 0x80, al
        lgdt [(gdtr-0xA8000)]           ; Set up a new GDT.
        mov eax, 0x1
        mov cr0, eax                    ; ... and enter pmode!
-       mov al, 0x03                    ; Say we got here.
-       out 0x80, al
        jmp long 0x10:continue          ; Now longjmp into the new code.
 [bits 32]
 continue:
-;      mov al, 0x04                    ; Now we're in protected mode.
-;      out 0x80, al
-       
        mov ax, 0x08                    ; Set up segment selectors.
        mov ds, ax
        mov es, ax
        mov fs, ax
        mov gs, ax
        mov ss, ax
-       mov esp, 0x1fffffff
+       mov esp, [dataptr]
 
-;      mov al, 0x05
+;      mov al, [cstat]
+;      add al, 1
 ;      out 0x80, al
-
-       mov al, [cstat]
-       add al, 1
-       out 0x80, al
-       mov [cstat], al
+;      mov [cstat], al
        
-       mov eax, 0x11223344
-       mov dword [status], eax
-
        mov dx, 0xCF8                   ; save off the old config value
        in dword eax, dx
        mov [esp-4], eax
@@ -85,14 +70,21 @@ continue:
        mov byte [eax+10], '2'
        mov byte [eax+11], 0x1F
        
-       mov dx, 0x3D4
+       mov dx, 0x3D4                   ; restore the old stuff
        mov al, [esp-6]
        out dx, al
-       
+
+       mov al, 0
+       mov edi, [dataptr+4]            ; clear BSS
+       mov ecx, [dataptr+8]
+       rep stosb
 
        mov dx, 0xCFC                   ; restore smramc
        mov al, [esp-5]
        out dx, al
+       
+       mov eax, [dataptr+12]
+       call eax
 
        mov dx, 0xCF8                   ; restore the old config value
        mov eax, [esp-4]
@@ -123,8 +115,12 @@ gdt:
        db 0xFF, 0xFF, 0x00, 0x00, 0x00, 0x9B, 0xCF, 0x00       ; code segment
        db 0xFF, 0xFF, 0x00, 0x80, 0x0A, 0x9B, 0xCF, 0x00       ; code segment for trampoline
 
-TIMES   512-($-$$) DB 0
-status:
-       dd 0xAA55AA55
 cstat:
        db 0x00
+
+TIMES   512-($-$$) DB 0
+dataptr:
+       ; 4 bytes of stack top
+       ; 4 bytes of BSS start
+       ; 4 bytes of BSS length
+       ; 4 bytes of C entry point
\ No newline at end of file