<header>
.model tiny
.code

ORG 100h

.data

<gleu>
SWITCHER:
call program 1
let it run for x seconds
push registers onto a stack
clear registers
run program 2
push registers onto a stack
clear registers
run program 3
do it all again
<program 1>
print out zomg multi
<program 2>
print out threading programs
<program 2>
in DOS!!!!!!!111

<end>
end Switcher

<apparently, i can use PUSHAD and POPAD as well>
<ZOMG YEY, found something, it is in gnu syntax T_T>
swap32: #(old,new)
mov 4 (%esp),%eax
mov 8 (%esp),%ecx
#save registers
push %ebp
push %ebx
push %esi
push %edi
#save the old stack
mov %esp,(%eax)
#load the new stack
mov (%ecx),%esp
#restore registers
pop %edi
pop %esi
pop %ebx
pop %ebp
ret