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#include "doselks.h"
int in_process = 0;
int intr_pending = 0;
unsigned int current_ds, current_stack;
struct process * proc;
/***************************************************************************
* These two routines to make doselks and the user program into co-routines.
*
* The Server calls run_cpu which runs the client.
* The client then does an int $80 which calls elks_int.
* Elks_int then returns to the caller of run_cpu.
*
* The return value is the value of AX when the int $80 occured.
* On return ES is set to the DS of the client program.
*
* The instruction times are for the 286
*
* If we were using a 486 then using mov's would be faster on the 286 they
* are the same speed but push/pop is smaller.
*/
#asm
.data
bx_temp: ! Tempoary storage for BX.
.word 0
.text ! The is where we store the current_ds in the _TEXT_ segment
cs_current_ds: ! for the elks_int routine
.word 0
#endasm
unsigned int run_cpu()
{
#asm
mov ax,ds ; 2
seg cs ! Store ds for return
mov [cs_current_ds],ax ; 5
cli ! We`re messing! ; 3
test [_intr_pending],#$FFFF ! Last chance ...
jz skp
sti
xor ax,ax
ret
skp:
push bp ; 3
push si ; 3
push di ; 3
mov [_current_stack],sp ; 5
mov ax,#1 ; 2
mov [_in_process],ax ; 5
mov sp,[_proc] ; 5
pop ax ! pppop ; 5
pop [bx_temp] ; 5
pop cx ; 5
pop dx ; 5
pop di ; 5
pop si ; 5
pop bp ; 5
pop es ; 5
mov bx,sp ! Switch to client stack ; 2
mov ss,[bx+8] ! SS ; 5
mov sp,[bx+10] ! SP ; 5
push [bx+6] ! flags ; 5
push [bx+4] ! CS ; 5
push [bx+2] ! PC ; 5
push [bx+0] ! DS ; 5
mov bx,[bx_temp] ; 5
pop ds ; 5
iret ; 17
#endasm
}
unsigned int elks_int()
{
#asm
.text
cli ; 3
push ds ; 3
push cs ; 3
pop ds ; 5
mov ds,[cs_current_ds] ; 5
mov [bx_temp],bx ; 3
mov bx,[_proc] ; 5
add bx,#16 ; 2
pop [bx+0] ! DS ; 5
pop [bx+2] ! PC ; 5
pop [bx+4] ! CS ; 5
pop [bx+6] ! flags ; 5
mov [bx+8],ss ! SS ; 3
mov [bx+10],sp ! SP ; 3
mov sp,bx ! Ready for pppppush ; 2
mov bx,ds ; 2
mov ss,bx ; 2
push es ! wheeee ; 3
push bp ; 3
push si ; 3
push di ; 3
push dx ; 3
push cx ; 3
push [bx_temp] ; 5
push ax ! This is the return value, handy ; 3
mov sp,[_current_stack] ; 5
mov bx,#1 ; 2
mov [_in_process],bx ; 5
sti ! Finished F**** around with the stack ; 2
mov bx,[_proc] ; 5
mov es,[bx+16] ! Set ES to the client`s DS ; 5
pop di ; 5
pop si ; 5
pop bp ; 5
#endasm
}
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