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kernel
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kernel.asm optimizations from Arkady 

git-svn-id: https://svn.code.sf.net/p/freedos/svn/kernel/trunk@896 6ac86273-5f31-0410-b378-82cca8765d1b
This commit is contained in:
Bart Oldeman 2004-04-24 15:09:34 +00:00
parent ea23d33c2c
commit 2fcbfdb271
1 changed files with 8 additions and 16 deletions
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24
kernel/kernel.asm
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@ -123,7 +123,7 @@ kernel_start:
mov sp,init_tos mov sp,init_tos
int 12h ; move init text+data to higher memory int 12h ; move init text+data to higher memory
mov cl,6 mov cl,6
shl ax,cl shl ax,cl ; convert kb to para
mov dx,15 + init_end wrt INIT_TEXT mov dx,15 + init_end wrt INIT_TEXT
mov cl,4 mov cl,4
shr dx,cl shr dx,cl
@ -136,35 +136,27 @@ kernel_start:
sti ; now enable them sti ; now enable them
mov ax,cs mov ax,cs
mov dx,__InitTextStart wrt HMA_TEXT ; para aligned mov dx,__InitTextStart wrt HMA_TEXT ; para aligned
shr dx,cl
%ifdef WATCOM %ifdef WATCOM
mov si,dx add ax,dx
mov cl,4
shr si,cl
add ax,si
%endif %endif
mov ds,ax mov ds,ax
mov cx,-2 + init_end wrt INIT_TEXT ; word aligned mov si,-2 + init_end wrt INIT_TEXT ; word aligned
mov si,cx lea cx,[si+2]
mov di,cx mov di,si
shr cx,1 shr cx,1
inc cx
std ; if there's overlap only std is safe std ; if there's overlap only std is safe
rep movsw rep movsw
; move HMA_TEXT to higher memory ; move HMA_TEXT to higher memory
mov si,dx ; si = __InitTextStart wrt HMA_TEXT
mov cl,4
shr dx,cl
sub ax,dx sub ax,dx
mov ds,ax ; ds = HMA_TEXT mov ds,ax ; ds = HMA_TEXT
mov ax,es mov ax,es
sub ax,dx sub ax,dx
mov es,ax ; es = new HMA_TEXT mov es,ax ; es = new HMA_TEXT
mov cx,si ; cx = __InitTextStart wrt HMA_TEXT mov si,-2 + __InitTextStart wrt HMA_TEXT
dec si lea cx,[si+2]
dec si
mov di,si mov di,si
shr cx,1 shr cx,1
rep movsw rep movsw